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jashkenas--coffeescript/test/classes.coffee

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# Classes
# -------
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# * Class Definition
# * Class Instantiation
# * Inheritance and Super
[CS2] Compile class constructors to ES2015 classes (#4354) * Compile classes to ES2015 classes Rather than compiling classes to named functions with prototype and class assignments, they are now compiled to ES2015 class declarations. Backwards compatibility has been maintained by compiling ES2015- incompatible properties as prototype or class assignments. `super` continues to be compiled as before. Where possible, classes will be compiled "bare", without an enclosing IIFE. This is possible when the class contains only ES2015 compatible expressions (methods and static methods), and has no parent (this last constraint is a result of the legacy `super` compilation, and could be removed once ES2015 `super` is being used). Classes are still assigned to variables to maintain compatibility for assigned class expressions. There are a few changes to existing functionality that could break backwards compatibility: - Derived constructors that deliberately don't call `super` are no longer possible. ES2015 derived classes can't use `this` unless the parent constructor has been called, so it's now called implicitly when not present. - As a consequence of the above, derived constructors with @ parameters or bound methods and explicit `super` calls are not allowed. The implicit `super` must be used in these cases. * Add tests to verify class interoperability with ES * Refactor class nodes to separate executable body logic Logic has been redistributed amongst the class nodes so that: - `Class` contains the logic necessary to compile an ES class declaration. - `ExecutableClassBody` contains the logic necessary to compile CS' class extensions that require an executable class body. `Class` still necessarily contains logic to determine whether an expression is valid in an ES class initializer or not. If any invalid expressions are found then `Class` will wrap itself in an `ExecutableClassBody` when compiling. * Rename `Code#static` to `Code#isStatic` This naming is more consistent with other `Code` flags. * Output anonymous classes when possible Anonymous classes can be output when: - The class has no parent. The current super compilation needs a class variable to reference. This condition will go away when ES2015 super is in use. - The class contains no bound static methods. Bound static methods have their context set to the class name. * Throw errors at compile time for async or generator constructors * Improve handling of anonymous classes Anonymous classes are now always anonymous. If a name is required (e.g. for bound static methods or derived classes) then the class is compiled in an `ExecutableClassBody` which will give the anonymous class a stable reference. * Add a `replaceInContext` method to `Node` `replaceInContext` will traverse children looking for a node for which `match` returns true. Once found, the matching node will be replaced by the result of calling `replacement`. * Separate `this` assignments from function parameters This change has been made to simplify two future changes: 1. Outputting `@`-param assignments after a `super` call. In this case it is necessary that non-`@` parameters are available before `super` is called, so destructuring has to happen before `this` assignment. 2. Compiling destructured assignment to ES6 In this case also destructuring has to happen before `this`, as destructuring can happen in the arguments list, but `this` assignment can not. A bonus side-effect is that default values for `@` params are now output as ES6 default parameters, e.g. (@a = 1) -> becomes function a (a = 1) { this.a = a; } * Change `super` handling in class constructors Inside an ES derived constructor (a constructor for a class that extends another class), it is impossible to access `this` until `super` has been called. This conflicts with CoffeeScript's `@`-param and bound method features, which compile to `this` references at the top of a function body. For example: class B extends A constructor: (@param) -> super method: => This would compile to something like: class B extends A { constructor (param) { this.param = param; this.method = bind(this.method, this); super(...arguments); } } This would break in an ES-compliant runtime as there are `this` references before the call to `super`. Before this commit we were dealing with this by injecting an implicit `super` call into derived constructors that do not already have an explicit `super` call. Furthermore, we would disallow explicit `super` calls in derived constructors that used bound methods or `@`-params, meaning the above example would need to be rewritten as: class B extends A constructor: (@param) -> method: => This would result in a call to `super(...arguments)` being generated as the first expression in `B#constructor`. Whilst this approach seems to work pretty well, and is arguably more convenient than having to manually call `super` when you don't particularly care about the arguments, it does introduce some 'magic' and separation from ES, and would likely be a pain point in a project that made use of significant constructor overriding. This commit introduces a mechanism through which `super` in constructors is 'expanded' to include any generated `this` assignments, whilst retaining the same semantics of a super call. The first example above now compiles to something like: class B extends A { constructor (param) { var ref ref = super(...arguments), this.param = param, this.method = bind(this.method, this), ref; } } * Improve `super` handling in constructors Rather than functions expanding their `super` calls, the `SuperCall` node can now be given a list of `thisAssignments` to apply when it is compiled. This allows us to use the normal compiler machinery to determine whether the `super` result needs to be cached, whether it appears inline or not, etc. * Fix anonymous classes at the top level Anonymous classes in ES are only valid within expressions. If an anonymous class is at the top level it will now be wrapped in parenthses to force it into an expression. * Re-add Parens wrapper around executable class bodies This was lost in the refactoring, but it necessary to ensure `new class ...` works as expected when there's an executable body. * Throw compiler errors for badly configured derived constructors Rather than letting them become runtime errors, the following checks are now performed when compiling a derived constructor: - The constructor **must** include a call to `super`. - The constructor **must not** reference `this` in the function body before `super` has been called. * Add some tests exercising new class behaviour - async methods in classes - `this` access after `super` in extended classes - constructor super in arrow functions - constructor functions can't be async - constructor functions can't be generators - derived constructors must call super - derived constructors can't reference `this` before calling super - generator methods in classes - 'new' target * Improve constructor `super` errors Add a check for `super` in non-extended class constructors, and explicitly mention derived constructors in the "can't reference this before super" error. * Fix compilation of multiple `super` paths in derived constructors `super` can only be called once, but it can be called conditionally from multiple locations. The chosen fix is to add the `this` assignments to every super call. * Additional class tests, added as a separate file to simplify testing and merging. Some methods are commented out because they currently throw and I'm not sure how to test for compilation errors like those. There is also one test which I deliberately left without passing, `super` in an external prototype override. This test should 'pass' but is really a variation on the failing `super only allowed in an instance method` tests above it. * Changes to the tests. Found bug in super in prototype method. fixed. * Added failing test back in, dealing with bound functions in external prototype overrides. * Located a bug in the compiler relating to assertions and escaped ES6 classes. * Move tests from classes-additional.coffee into classes.coffee; comment out console.log * Cleaned up tests and made changes based on feedback. Test at the end still has issues, but it's commented out for now. * Make HoistTarget.expand recursive It's possible that a hoisted node may itself contain hoisted nodes (e.g. a class method inside a class method). For this to work the hoisted fragments need to be expanded recursively. * Uncomment final test in classes.coffee The test case now compiles, however another issue is affecting the test due to the error for `this` before `super` triggering based on source order rather than execution order. These have been commented out for now. * Fixed last test TODOs in test/classes.coffee Turns out an expression like `this.foo = super()` won't run in JS as it attempts to lookup `this` before evaluating `super` (i.e. throws "this is not defined"). * Added more tests for compatability checks, statics, prototypes and ES6 expectations. Cleaned test "nested classes with super". * Changes to reflect feedback and to comment out issues that will be addressed seperately. * Clean up test/classes.coffee - Trim trailing whitespace. - Rephrase a condition to be more idiomatic. * Remove check for `super` in derived constructors In order to be usable at runtime, an extended ES class must call `super` OR return an alternative object. This check prevented the latter case, and checking for an alternative return can't be completed statically without control flow analysis. * Disallow 'super' in constructor parameter defaults There are many edge cases when combining 'super' in parameter defaults with @-parameters and bound functions (and potentially property initializers in the future). Rather than attempting to resolve these edge cases, 'super' is now explicitly disallowed in constructor parameter defaults. * Disallow @-params in derived constructors without 'super' @-parameters can't be assigned unless 'super' is called.
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# * ES2015+ Class Interoperability
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test "classes with a four-level inheritance chain", ->
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class Base
func: (string) ->
"zero/#{string}"
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@static: (string) ->
"static/#{string}"
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class FirstChild extends Base
func: (string) ->
super('one/') + string
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SecondChild = class extends FirstChild
func: (string) ->
super('two/') + string
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thirdCtor = ->
@array = [1, 2, 3]
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class ThirdChild extends SecondChild
[CS2] Compile class constructors to ES2015 classes (#4354) * Compile classes to ES2015 classes Rather than compiling classes to named functions with prototype and class assignments, they are now compiled to ES2015 class declarations. Backwards compatibility has been maintained by compiling ES2015- incompatible properties as prototype or class assignments. `super` continues to be compiled as before. Where possible, classes will be compiled "bare", without an enclosing IIFE. This is possible when the class contains only ES2015 compatible expressions (methods and static methods), and has no parent (this last constraint is a result of the legacy `super` compilation, and could be removed once ES2015 `super` is being used). Classes are still assigned to variables to maintain compatibility for assigned class expressions. There are a few changes to existing functionality that could break backwards compatibility: - Derived constructors that deliberately don't call `super` are no longer possible. ES2015 derived classes can't use `this` unless the parent constructor has been called, so it's now called implicitly when not present. - As a consequence of the above, derived constructors with @ parameters or bound methods and explicit `super` calls are not allowed. The implicit `super` must be used in these cases. * Add tests to verify class interoperability with ES * Refactor class nodes to separate executable body logic Logic has been redistributed amongst the class nodes so that: - `Class` contains the logic necessary to compile an ES class declaration. - `ExecutableClassBody` contains the logic necessary to compile CS' class extensions that require an executable class body. `Class` still necessarily contains logic to determine whether an expression is valid in an ES class initializer or not. If any invalid expressions are found then `Class` will wrap itself in an `ExecutableClassBody` when compiling. * Rename `Code#static` to `Code#isStatic` This naming is more consistent with other `Code` flags. * Output anonymous classes when possible Anonymous classes can be output when: - The class has no parent. The current super compilation needs a class variable to reference. This condition will go away when ES2015 super is in use. - The class contains no bound static methods. Bound static methods have their context set to the class name. * Throw errors at compile time for async or generator constructors * Improve handling of anonymous classes Anonymous classes are now always anonymous. If a name is required (e.g. for bound static methods or derived classes) then the class is compiled in an `ExecutableClassBody` which will give the anonymous class a stable reference. * Add a `replaceInContext` method to `Node` `replaceInContext` will traverse children looking for a node for which `match` returns true. Once found, the matching node will be replaced by the result of calling `replacement`. * Separate `this` assignments from function parameters This change has been made to simplify two future changes: 1. Outputting `@`-param assignments after a `super` call. In this case it is necessary that non-`@` parameters are available before `super` is called, so destructuring has to happen before `this` assignment. 2. Compiling destructured assignment to ES6 In this case also destructuring has to happen before `this`, as destructuring can happen in the arguments list, but `this` assignment can not. A bonus side-effect is that default values for `@` params are now output as ES6 default parameters, e.g. (@a = 1) -> becomes function a (a = 1) { this.a = a; } * Change `super` handling in class constructors Inside an ES derived constructor (a constructor for a class that extends another class), it is impossible to access `this` until `super` has been called. This conflicts with CoffeeScript's `@`-param and bound method features, which compile to `this` references at the top of a function body. For example: class B extends A constructor: (@param) -> super method: => This would compile to something like: class B extends A { constructor (param) { this.param = param; this.method = bind(this.method, this); super(...arguments); } } This would break in an ES-compliant runtime as there are `this` references before the call to `super`. Before this commit we were dealing with this by injecting an implicit `super` call into derived constructors that do not already have an explicit `super` call. Furthermore, we would disallow explicit `super` calls in derived constructors that used bound methods or `@`-params, meaning the above example would need to be rewritten as: class B extends A constructor: (@param) -> method: => This would result in a call to `super(...arguments)` being generated as the first expression in `B#constructor`. Whilst this approach seems to work pretty well, and is arguably more convenient than having to manually call `super` when you don't particularly care about the arguments, it does introduce some 'magic' and separation from ES, and would likely be a pain point in a project that made use of significant constructor overriding. This commit introduces a mechanism through which `super` in constructors is 'expanded' to include any generated `this` assignments, whilst retaining the same semantics of a super call. The first example above now compiles to something like: class B extends A { constructor (param) { var ref ref = super(...arguments), this.param = param, this.method = bind(this.method, this), ref; } } * Improve `super` handling in constructors Rather than functions expanding their `super` calls, the `SuperCall` node can now be given a list of `thisAssignments` to apply when it is compiled. This allows us to use the normal compiler machinery to determine whether the `super` result needs to be cached, whether it appears inline or not, etc. * Fix anonymous classes at the top level Anonymous classes in ES are only valid within expressions. If an anonymous class is at the top level it will now be wrapped in parenthses to force it into an expression. * Re-add Parens wrapper around executable class bodies This was lost in the refactoring, but it necessary to ensure `new class ...` works as expected when there's an executable body. * Throw compiler errors for badly configured derived constructors Rather than letting them become runtime errors, the following checks are now performed when compiling a derived constructor: - The constructor **must** include a call to `super`. - The constructor **must not** reference `this` in the function body before `super` has been called. * Add some tests exercising new class behaviour - async methods in classes - `this` access after `super` in extended classes - constructor super in arrow functions - constructor functions can't be async - constructor functions can't be generators - derived constructors must call super - derived constructors can't reference `this` before calling super - generator methods in classes - 'new' target * Improve constructor `super` errors Add a check for `super` in non-extended class constructors, and explicitly mention derived constructors in the "can't reference this before super" error. * Fix compilation of multiple `super` paths in derived constructors `super` can only be called once, but it can be called conditionally from multiple locations. The chosen fix is to add the `this` assignments to every super call. * Additional class tests, added as a separate file to simplify testing and merging. Some methods are commented out because they currently throw and I'm not sure how to test for compilation errors like those. There is also one test which I deliberately left without passing, `super` in an external prototype override. This test should 'pass' but is really a variation on the failing `super only allowed in an instance method` tests above it. * Changes to the tests. Found bug in super in prototype method. fixed. * Added failing test back in, dealing with bound functions in external prototype overrides. * Located a bug in the compiler relating to assertions and escaped ES6 classes. * Move tests from classes-additional.coffee into classes.coffee; comment out console.log * Cleaned up tests and made changes based on feedback. Test at the end still has issues, but it's commented out for now. * Make HoistTarget.expand recursive It's possible that a hoisted node may itself contain hoisted nodes (e.g. a class method inside a class method). For this to work the hoisted fragments need to be expanded recursively. * Uncomment final test in classes.coffee The test case now compiles, however another issue is affecting the test due to the error for `this` before `super` triggering based on source order rather than execution order. These have been commented out for now. * Fixed last test TODOs in test/classes.coffee Turns out an expression like `this.foo = super()` won't run in JS as it attempts to lookup `this` before evaluating `super` (i.e. throws "this is not defined"). * Added more tests for compatability checks, statics, prototypes and ES6 expectations. Cleaned test "nested classes with super". * Changes to reflect feedback and to comment out issues that will be addressed seperately. * Clean up test/classes.coffee - Trim trailing whitespace. - Rephrase a condition to be more idiomatic. * Remove check for `super` in derived constructors In order to be usable at runtime, an extended ES class must call `super` OR return an alternative object. This check prevented the latter case, and checking for an alternative return can't be completed statically without control flow analysis. * Disallow 'super' in constructor parameter defaults There are many edge cases when combining 'super' in parameter defaults with @-parameters and bound functions (and potentially property initializers in the future). Rather than attempting to resolve these edge cases, 'super' is now explicitly disallowed in constructor parameter defaults. * Disallow @-params in derived constructors without 'super' @-parameters can't be assigned unless 'super' is called.
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constructor: ->
super()
thirdCtor.call this
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# Gratuitous comment for testing.
func: (string) ->
super('three/') + string
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result = (new ThirdChild).func 'four'
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ok result is 'zero/one/two/three/four'
ok Base.static('word') is 'static/word'
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ok (new ThirdChild).array.join(' ') is '1 2 3'
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test "constructors with inheritance and super", ->
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identity = (f) -> f
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class TopClass
constructor: (arg) ->
@prop = 'top-' + arg
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class SuperClass extends TopClass
constructor: (arg) ->
identity super 'super-' + arg
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class SubClass extends SuperClass
constructor: ->
identity super 'sub'
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ok (new SubClass).prop is 'top-super-sub'
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[CS2] Compile all super calls to ES2015 super (#4424) * Compile all super calls to ES2015 super This breaks using `super` in non-methods, meaning several tests are failing. Self-compilation still works. * Use bound functions for IIFEs containing `super` `super` can only be called directly in a method, or in an arrow function. * Fix handling of `class @A extends A` This behaviour worked 'for free' when the parent reference was being cached by the executable class body wrapper. There now needs to be special handling in place to check if the parent name matches the class name, and if so to cache the parent reference. * Fix tests broken by compiling ES2015 `super` * Disallow bare super This removes syntax support for 'bare' super calls, e.g.: class B extends A constructor: -> super `super` must now always be followed with arguments like a regular function call. This also removes the capability of implicitly forwarding arguments. The above can be equivalently be written as: class B extends A constructor: -> super arguments... * Support super with accessors `super` with following accessor(s) is now compiled to ES2015 equivalents. In particular, expressions such as `super.name`, `super[name]`, and also `super.name.prop` are all now valid, and can be used as expected as calls (i.e. `super.name()`) or in expressions (i.e. `if super.name? ...`). `super` without accessors is compiled to a constructor super call in a constructor, and otherwise, as before, to a super call to the method of the same name, i.e. speak: -> super() ...is equivalent to speak: -> super.speak() A neat side-effect of the changes is that existential calls now work properly with super, meaning `super?()` will only call if the super property exists (and is a function). This is not valid for super in constructors. * Prevent calling `super` methods with `new` This fixes a bug in the previous super handling whereby using the `new` operator with a `super` call would silently drop the `new`. This is now an explicit compiler error, as it is invalid JS at runtime. * Clean up some old super handling code This was mostly code for tracking the source classes and variables for methods, which were needed to build the old lookups on `__super__`. * Add TODO to improve bare super parse error * Add some TODOs to improve some of the class tests
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test "'super' with accessors", ->
class Base
m: -> 4
n: -> 5
o: -> 6
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[CS2] Compile all super calls to ES2015 super (#4424) * Compile all super calls to ES2015 super This breaks using `super` in non-methods, meaning several tests are failing. Self-compilation still works. * Use bound functions for IIFEs containing `super` `super` can only be called directly in a method, or in an arrow function. * Fix handling of `class @A extends A` This behaviour worked 'for free' when the parent reference was being cached by the executable class body wrapper. There now needs to be special handling in place to check if the parent name matches the class name, and if so to cache the parent reference. * Fix tests broken by compiling ES2015 `super` * Disallow bare super This removes syntax support for 'bare' super calls, e.g.: class B extends A constructor: -> super `super` must now always be followed with arguments like a regular function call. This also removes the capability of implicitly forwarding arguments. The above can be equivalently be written as: class B extends A constructor: -> super arguments... * Support super with accessors `super` with following accessor(s) is now compiled to ES2015 equivalents. In particular, expressions such as `super.name`, `super[name]`, and also `super.name.prop` are all now valid, and can be used as expected as calls (i.e. `super.name()`) or in expressions (i.e. `if super.name? ...`). `super` without accessors is compiled to a constructor super call in a constructor, and otherwise, as before, to a super call to the method of the same name, i.e. speak: -> super() ...is equivalent to speak: -> super.speak() A neat side-effect of the changes is that existential calls now work properly with super, meaning `super?()` will only call if the super property exists (and is a function). This is not valid for super in constructors. * Prevent calling `super` methods with `new` This fixes a bug in the previous super handling whereby using the `new` operator with a `super` call would silently drop the `new`. This is now an explicit compiler error, as it is invalid JS at runtime. * Clean up some old super handling code This was mostly code for tracking the source classes and variables for methods, which were needed to build the old lookups on `__super__`. * Add TODO to improve bare super parse error * Add some TODOs to improve some of the class tests
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name = 'o'
class A extends Base
m: -> super()
n: -> super.n()
"#{name}": -> super()
p: -> super[name]()
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[CS2] Compile all super calls to ES2015 super (#4424) * Compile all super calls to ES2015 super This breaks using `super` in non-methods, meaning several tests are failing. Self-compilation still works. * Use bound functions for IIFEs containing `super` `super` can only be called directly in a method, or in an arrow function. * Fix handling of `class @A extends A` This behaviour worked 'for free' when the parent reference was being cached by the executable class body wrapper. There now needs to be special handling in place to check if the parent name matches the class name, and if so to cache the parent reference. * Fix tests broken by compiling ES2015 `super` * Disallow bare super This removes syntax support for 'bare' super calls, e.g.: class B extends A constructor: -> super `super` must now always be followed with arguments like a regular function call. This also removes the capability of implicitly forwarding arguments. The above can be equivalently be written as: class B extends A constructor: -> super arguments... * Support super with accessors `super` with following accessor(s) is now compiled to ES2015 equivalents. In particular, expressions such as `super.name`, `super[name]`, and also `super.name.prop` are all now valid, and can be used as expected as calls (i.e. `super.name()`) or in expressions (i.e. `if super.name? ...`). `super` without accessors is compiled to a constructor super call in a constructor, and otherwise, as before, to a super call to the method of the same name, i.e. speak: -> super() ...is equivalent to speak: -> super.speak() A neat side-effect of the changes is that existential calls now work properly with super, meaning `super?()` will only call if the super property exists (and is a function). This is not valid for super in constructors. * Prevent calling `super` methods with `new` This fixes a bug in the previous super handling whereby using the `new` operator with a `super` call would silently drop the `new`. This is now an explicit compiler error, as it is invalid JS at runtime. * Clean up some old super handling code This was mostly code for tracking the source classes and variables for methods, which were needed to build the old lookups on `__super__`. * Add TODO to improve bare super parse error * Add some TODOs to improve some of the class tests
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a = new A
eq 4, a.m()
eq 5, a.n()
eq 6, a.o()
eq 6, a.p()
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[CS2] Compile all super calls to ES2015 super (#4424) * Compile all super calls to ES2015 super This breaks using `super` in non-methods, meaning several tests are failing. Self-compilation still works. * Use bound functions for IIFEs containing `super` `super` can only be called directly in a method, or in an arrow function. * Fix handling of `class @A extends A` This behaviour worked 'for free' when the parent reference was being cached by the executable class body wrapper. There now needs to be special handling in place to check if the parent name matches the class name, and if so to cache the parent reference. * Fix tests broken by compiling ES2015 `super` * Disallow bare super This removes syntax support for 'bare' super calls, e.g.: class B extends A constructor: -> super `super` must now always be followed with arguments like a regular function call. This also removes the capability of implicitly forwarding arguments. The above can be equivalently be written as: class B extends A constructor: -> super arguments... * Support super with accessors `super` with following accessor(s) is now compiled to ES2015 equivalents. In particular, expressions such as `super.name`, `super[name]`, and also `super.name.prop` are all now valid, and can be used as expected as calls (i.e. `super.name()`) or in expressions (i.e. `if super.name? ...`). `super` without accessors is compiled to a constructor super call in a constructor, and otherwise, as before, to a super call to the method of the same name, i.e. speak: -> super() ...is equivalent to speak: -> super.speak() A neat side-effect of the changes is that existential calls now work properly with super, meaning `super?()` will only call if the super property exists (and is a function). This is not valid for super in constructors. * Prevent calling `super` methods with `new` This fixes a bug in the previous super handling whereby using the `new` operator with a `super` call would silently drop the `new`. This is now an explicit compiler error, as it is invalid JS at runtime. * Clean up some old super handling code This was mostly code for tracking the source classes and variables for methods, which were needed to build the old lookups on `__super__`. * Add TODO to improve bare super parse error * Add some TODOs to improve some of the class tests
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test "soaked 'super' invocation", ->
class Base
method: -> 2
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[CS2] Compile all super calls to ES2015 super (#4424) * Compile all super calls to ES2015 super This breaks using `super` in non-methods, meaning several tests are failing. Self-compilation still works. * Use bound functions for IIFEs containing `super` `super` can only be called directly in a method, or in an arrow function. * Fix handling of `class @A extends A` This behaviour worked 'for free' when the parent reference was being cached by the executable class body wrapper. There now needs to be special handling in place to check if the parent name matches the class name, and if so to cache the parent reference. * Fix tests broken by compiling ES2015 `super` * Disallow bare super This removes syntax support for 'bare' super calls, e.g.: class B extends A constructor: -> super `super` must now always be followed with arguments like a regular function call. This also removes the capability of implicitly forwarding arguments. The above can be equivalently be written as: class B extends A constructor: -> super arguments... * Support super with accessors `super` with following accessor(s) is now compiled to ES2015 equivalents. In particular, expressions such as `super.name`, `super[name]`, and also `super.name.prop` are all now valid, and can be used as expected as calls (i.e. `super.name()`) or in expressions (i.e. `if super.name? ...`). `super` without accessors is compiled to a constructor super call in a constructor, and otherwise, as before, to a super call to the method of the same name, i.e. speak: -> super() ...is equivalent to speak: -> super.speak() A neat side-effect of the changes is that existential calls now work properly with super, meaning `super?()` will only call if the super property exists (and is a function). This is not valid for super in constructors. * Prevent calling `super` methods with `new` This fixes a bug in the previous super handling whereby using the `new` operator with a `super` call would silently drop the `new`. This is now an explicit compiler error, as it is invalid JS at runtime. * Clean up some old super handling code This was mostly code for tracking the source classes and variables for methods, which were needed to build the old lookups on `__super__`. * Add TODO to improve bare super parse error * Add some TODOs to improve some of the class tests
2017-02-04 15:03:17 -05:00
class A extends Base
method: -> super?()
noMethod: -> super?()
2010-12-29 00:48:54 -05:00
[CS2] Compile all super calls to ES2015 super (#4424) * Compile all super calls to ES2015 super This breaks using `super` in non-methods, meaning several tests are failing. Self-compilation still works. * Use bound functions for IIFEs containing `super` `super` can only be called directly in a method, or in an arrow function. * Fix handling of `class @A extends A` This behaviour worked 'for free' when the parent reference was being cached by the executable class body wrapper. There now needs to be special handling in place to check if the parent name matches the class name, and if so to cache the parent reference. * Fix tests broken by compiling ES2015 `super` * Disallow bare super This removes syntax support for 'bare' super calls, e.g.: class B extends A constructor: -> super `super` must now always be followed with arguments like a regular function call. This also removes the capability of implicitly forwarding arguments. The above can be equivalently be written as: class B extends A constructor: -> super arguments... * Support super with accessors `super` with following accessor(s) is now compiled to ES2015 equivalents. In particular, expressions such as `super.name`, `super[name]`, and also `super.name.prop` are all now valid, and can be used as expected as calls (i.e. `super.name()`) or in expressions (i.e. `if super.name? ...`). `super` without accessors is compiled to a constructor super call in a constructor, and otherwise, as before, to a super call to the method of the same name, i.e. speak: -> super() ...is equivalent to speak: -> super.speak() A neat side-effect of the changes is that existential calls now work properly with super, meaning `super?()` will only call if the super property exists (and is a function). This is not valid for super in constructors. * Prevent calling `super` methods with `new` This fixes a bug in the previous super handling whereby using the `new` operator with a `super` call would silently drop the `new`. This is now an explicit compiler error, as it is invalid JS at runtime. * Clean up some old super handling code This was mostly code for tracking the source classes and variables for methods, which were needed to build the old lookups on `__super__`. * Add TODO to improve bare super parse error * Add some TODOs to improve some of the class tests
2017-02-04 15:03:17 -05:00
a = new A
eq 2, a.method()
eq undefined, a.noMethod()
2010-12-29 00:48:54 -05:00
[CS2] Compile all super calls to ES2015 super (#4424) * Compile all super calls to ES2015 super This breaks using `super` in non-methods, meaning several tests are failing. Self-compilation still works. * Use bound functions for IIFEs containing `super` `super` can only be called directly in a method, or in an arrow function. * Fix handling of `class @A extends A` This behaviour worked 'for free' when the parent reference was being cached by the executable class body wrapper. There now needs to be special handling in place to check if the parent name matches the class name, and if so to cache the parent reference. * Fix tests broken by compiling ES2015 `super` * Disallow bare super This removes syntax support for 'bare' super calls, e.g.: class B extends A constructor: -> super `super` must now always be followed with arguments like a regular function call. This also removes the capability of implicitly forwarding arguments. The above can be equivalently be written as: class B extends A constructor: -> super arguments... * Support super with accessors `super` with following accessor(s) is now compiled to ES2015 equivalents. In particular, expressions such as `super.name`, `super[name]`, and also `super.name.prop` are all now valid, and can be used as expected as calls (i.e. `super.name()`) or in expressions (i.e. `if super.name? ...`). `super` without accessors is compiled to a constructor super call in a constructor, and otherwise, as before, to a super call to the method of the same name, i.e. speak: -> super() ...is equivalent to speak: -> super.speak() A neat side-effect of the changes is that existential calls now work properly with super, meaning `super?()` will only call if the super property exists (and is a function). This is not valid for super in constructors. * Prevent calling `super` methods with `new` This fixes a bug in the previous super handling whereby using the `new` operator with a `super` call would silently drop the `new`. This is now an explicit compiler error, as it is invalid JS at runtime. * Clean up some old super handling code This was mostly code for tracking the source classes and variables for methods, which were needed to build the old lookups on `__super__`. * Add TODO to improve bare super parse error * Add some TODOs to improve some of the class tests
2017-02-04 15:03:17 -05:00
name = 'noMethod'
class B extends Base
"#{'method'}": -> super?()
"#{'noMethod'}": -> super?() ? super['method']()
2010-12-29 00:48:54 -05:00
[CS2] Compile all super calls to ES2015 super (#4424) * Compile all super calls to ES2015 super This breaks using `super` in non-methods, meaning several tests are failing. Self-compilation still works. * Use bound functions for IIFEs containing `super` `super` can only be called directly in a method, or in an arrow function. * Fix handling of `class @A extends A` This behaviour worked 'for free' when the parent reference was being cached by the executable class body wrapper. There now needs to be special handling in place to check if the parent name matches the class name, and if so to cache the parent reference. * Fix tests broken by compiling ES2015 `super` * Disallow bare super This removes syntax support for 'bare' super calls, e.g.: class B extends A constructor: -> super `super` must now always be followed with arguments like a regular function call. This also removes the capability of implicitly forwarding arguments. The above can be equivalently be written as: class B extends A constructor: -> super arguments... * Support super with accessors `super` with following accessor(s) is now compiled to ES2015 equivalents. In particular, expressions such as `super.name`, `super[name]`, and also `super.name.prop` are all now valid, and can be used as expected as calls (i.e. `super.name()`) or in expressions (i.e. `if super.name? ...`). `super` without accessors is compiled to a constructor super call in a constructor, and otherwise, as before, to a super call to the method of the same name, i.e. speak: -> super() ...is equivalent to speak: -> super.speak() A neat side-effect of the changes is that existential calls now work properly with super, meaning `super?()` will only call if the super property exists (and is a function). This is not valid for super in constructors. * Prevent calling `super` methods with `new` This fixes a bug in the previous super handling whereby using the `new` operator with a `super` call would silently drop the `new`. This is now an explicit compiler error, as it is invalid JS at runtime. * Clean up some old super handling code This was mostly code for tracking the source classes and variables for methods, which were needed to build the old lookups on `__super__`. * Add TODO to improve bare super parse error * Add some TODOs to improve some of the class tests
2017-02-04 15:03:17 -05:00
b = new B
eq 2, b.method()
eq 2, b.noMethod()
2010-12-29 00:48:54 -05:00
2011-03-11 21:55:26 -05:00
test "'@' referring to the current instance, and not being coerced into a call", ->
class ClassName
amI: ->
@ instanceof ClassName
obj = new ClassName
ok obj.amI()
test "super() calls in constructors of classes that are defined as object properties", ->
2010-12-29 00:48:54 -05:00
2011-03-11 21:55:26 -05:00
class Hive
constructor: (name) -> @name = name
2010-12-29 00:48:54 -05:00
2011-03-11 21:55:26 -05:00
class Hive.Bee extends Hive
[CS2] Compile all super calls to ES2015 super (#4424) * Compile all super calls to ES2015 super This breaks using `super` in non-methods, meaning several tests are failing. Self-compilation still works. * Use bound functions for IIFEs containing `super` `super` can only be called directly in a method, or in an arrow function. * Fix handling of `class @A extends A` This behaviour worked 'for free' when the parent reference was being cached by the executable class body wrapper. There now needs to be special handling in place to check if the parent name matches the class name, and if so to cache the parent reference. * Fix tests broken by compiling ES2015 `super` * Disallow bare super This removes syntax support for 'bare' super calls, e.g.: class B extends A constructor: -> super `super` must now always be followed with arguments like a regular function call. This also removes the capability of implicitly forwarding arguments. The above can be equivalently be written as: class B extends A constructor: -> super arguments... * Support super with accessors `super` with following accessor(s) is now compiled to ES2015 equivalents. In particular, expressions such as `super.name`, `super[name]`, and also `super.name.prop` are all now valid, and can be used as expected as calls (i.e. `super.name()`) or in expressions (i.e. `if super.name? ...`). `super` without accessors is compiled to a constructor super call in a constructor, and otherwise, as before, to a super call to the method of the same name, i.e. speak: -> super() ...is equivalent to speak: -> super.speak() A neat side-effect of the changes is that existential calls now work properly with super, meaning `super?()` will only call if the super property exists (and is a function). This is not valid for super in constructors. * Prevent calling `super` methods with `new` This fixes a bug in the previous super handling whereby using the `new` operator with a `super` call would silently drop the `new`. This is now an explicit compiler error, as it is invalid JS at runtime. * Clean up some old super handling code This was mostly code for tracking the source classes and variables for methods, which were needed to build the old lookups on `__super__`. * Add TODO to improve bare super parse error * Add some TODOs to improve some of the class tests
2017-02-04 15:03:17 -05:00
constructor: (name) -> super name
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maya = new Hive.Bee 'Maya'
ok maya.name is 'Maya'
2010-12-29 00:48:54 -05:00
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test "classes with JS-keyword properties", ->
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class Class
class: 'class'
name: -> @class
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instance = new Class
ok instance.class is 'class'
ok instance.name() is 'class'
2010-12-29 00:48:54 -05:00
test "Classes with methods that are pre-bound to the instance, or statically, to the class", ->
2010-12-29 00:48:54 -05:00
2011-03-11 21:55:26 -05:00
class Dog
constructor: (name) ->
@name = name
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bark: =>
"#{@name} woofs!"
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@static = =>
new this('Dog')
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spark = new Dog('Spark')
fido = new Dog('Fido')
fido.bark = spark.bark
ok fido.bark() is 'Spark woofs!'
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obj = func: Dog.static
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2011-03-11 21:55:26 -05:00
ok obj.func().name is 'Dog'
2010-12-29 00:48:54 -05:00
test "a bound function in a bound function", ->
class Mini
num: 10
generate: =>
for i in [1..3]
=>
@num
m = new Mini
eq (func() for func in m.generate()).join(' '), '10 10 10'
2011-03-11 21:55:26 -05:00
test "contructor called with varargs", ->
2010-12-29 00:48:54 -05:00
2011-03-11 21:55:26 -05:00
class Connection
constructor: (one, two, three) ->
[@one, @two, @three] = [one, two, three]
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out: ->
"#{@one}-#{@two}-#{@three}"
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list = [3, 2, 1]
conn = new Connection list...
ok conn instanceof Connection
ok conn.out() is '3-2-1'
2010-12-29 00:48:54 -05:00
2011-03-11 21:55:26 -05:00
test "calling super and passing along all arguments", ->
2010-12-29 00:48:54 -05:00
2011-03-11 21:55:26 -05:00
class Parent
method: (args...) -> @args = args
2010-12-29 00:48:54 -05:00
2011-03-11 21:55:26 -05:00
class Child extends Parent
[CS2] Compile all super calls to ES2015 super (#4424) * Compile all super calls to ES2015 super This breaks using `super` in non-methods, meaning several tests are failing. Self-compilation still works. * Use bound functions for IIFEs containing `super` `super` can only be called directly in a method, or in an arrow function. * Fix handling of `class @A extends A` This behaviour worked 'for free' when the parent reference was being cached by the executable class body wrapper. There now needs to be special handling in place to check if the parent name matches the class name, and if so to cache the parent reference. * Fix tests broken by compiling ES2015 `super` * Disallow bare super This removes syntax support for 'bare' super calls, e.g.: class B extends A constructor: -> super `super` must now always be followed with arguments like a regular function call. This also removes the capability of implicitly forwarding arguments. The above can be equivalently be written as: class B extends A constructor: -> super arguments... * Support super with accessors `super` with following accessor(s) is now compiled to ES2015 equivalents. In particular, expressions such as `super.name`, `super[name]`, and also `super.name.prop` are all now valid, and can be used as expected as calls (i.e. `super.name()`) or in expressions (i.e. `if super.name? ...`). `super` without accessors is compiled to a constructor super call in a constructor, and otherwise, as before, to a super call to the method of the same name, i.e. speak: -> super() ...is equivalent to speak: -> super.speak() A neat side-effect of the changes is that existential calls now work properly with super, meaning `super?()` will only call if the super property exists (and is a function). This is not valid for super in constructors. * Prevent calling `super` methods with `new` This fixes a bug in the previous super handling whereby using the `new` operator with a `super` call would silently drop the `new`. This is now an explicit compiler error, as it is invalid JS at runtime. * Clean up some old super handling code This was mostly code for tracking the source classes and variables for methods, which were needed to build the old lookups on `__super__`. * Add TODO to improve bare super parse error * Add some TODOs to improve some of the class tests
2017-02-04 15:03:17 -05:00
method: -> super arguments...
2010-12-29 00:48:54 -05:00
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c = new Child
c.method 1, 2, 3, 4
ok c.args.join(' ') is '1 2 3 4'
2010-12-29 00:48:54 -05:00
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test "classes wrapped in decorators", ->
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func = (klass) ->
klass::prop = 'value'
klass
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func class Test
prop2: 'value2'
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ok (new Test).prop is 'value'
ok (new Test).prop2 is 'value2'
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test "anonymous classes", ->
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obj =
klass: class
method: -> 'value'
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instance = new obj.klass
ok instance.method() is 'value'
2010-12-29 00:48:54 -05:00
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test "Implicit objects as static properties", ->
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2011-03-11 21:55:26 -05:00
class Static
@static =
one: 1
two: 2
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ok Static.static.one is 1
ok Static.static.two is 2
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test "nothing classes", ->
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c = class
ok c instanceof Function
2011-12-24 07:04:34 -05:00
2011-12-15 12:29:03 -05:00
test "classes with static-level implicit objects", ->
2011-12-24 07:04:34 -05:00
2011-12-15 12:29:03 -05:00
class A
@static = one: 1
two: 2
2011-12-24 07:04:34 -05:00
2011-12-15 12:29:03 -05:00
class B
@static = one: 1,
two: 2
2011-12-24 07:04:34 -05:00
2011-12-15 12:29:03 -05:00
eq A.static.one, 1
eq A.static.two, undefined
eq (new A).two, 2
2011-12-24 07:04:34 -05:00
2011-12-15 12:29:03 -05:00
eq B.static.one, 1
eq B.static.two, 2
eq (new B).two, undefined
2010-12-29 00:48:54 -05:00
2011-03-11 21:55:26 -05:00
test "classes with value'd constructors", ->
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counter = 0
classMaker = ->
inner = ++counter
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->
@value = inner
@
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class One
constructor: classMaker()
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class Two
constructor: classMaker()
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eq (new One).value, 1
eq (new Two).value, 2
eq (new One).value, 1
eq (new Two).value, 2
2010-12-29 00:48:54 -05:00
test "executable class bodies", ->
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2011-03-11 21:55:26 -05:00
class A
if true
b: 'b'
else
c: 'c'
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a = new A
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eq a.b, 'b'
eq a.c, undefined
2010-12-29 00:48:54 -05:00
test "#2502: parenthesizing inner object values", ->
class A
category: (type: 'string')
sections: (type: 'number', default: 0)
eq (new A).category.type, 'string'
eq (new A).sections.default, 0
test "conditional prototype property assignment", ->
debug = false
class Person
if debug
age: -> 10
else
age: -> 20
eq (new Person).age(), 20
2011-03-11 21:55:26 -05:00
test "mild metaprogramming", ->
2010-12-29 00:48:54 -05:00
2011-03-11 21:55:26 -05:00
class Base
@attr: (name) ->
@::[name] = (val) ->
if arguments.length > 0
@["_#{name}"] = val
else
@["_#{name}"]
2010-12-29 00:48:54 -05:00
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class Robot extends Base
@attr 'power'
@attr 'speed'
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robby = new Robot
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ok robby.power() is undefined
2010-12-29 00:48:54 -05:00
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robby.power 11
robby.speed Infinity
eq robby.power(), 11
eq robby.speed(), Infinity
test "namespaced classes do not reserve their function name in outside scope", ->
one = {}
two = {}
class one.Klass
@label = "one"
class two.Klass
@label = "two"
eq typeof Klass, 'undefined'
eq one.Klass.label, 'one'
eq two.Klass.label, 'two'
test "nested classes", ->
class Outer
constructor: ->
@label = 'outer'
class @Inner
constructor: ->
@label = 'inner'
eq (new Outer).label, 'outer'
eq (new Outer.Inner).label, 'inner'
test "variables in constructor bodies are correctly scoped", ->
class A
x = 1
2010-12-29 00:48:54 -05:00
constructor: ->
2011-03-11 21:55:26 -05:00
x = 10
y = 20
y = 2
captured: ->
{x, y}
a = new A
eq a.captured().x, 10
eq a.captured().y, 2
2010-12-29 00:48:54 -05:00
2011-03-11 21:55:26 -05:00
test "Issue #924: Static methods in nested classes", ->
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2011-03-11 21:55:26 -05:00
class A
@B: class
@c = -> 5
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eq A.B.c(), 5
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2011-03-11 21:55:26 -05:00
test "`class extends this`", ->
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2011-03-11 21:55:26 -05:00
class A
func: -> 'A'
2010-12-29 00:48:54 -05:00
2011-03-11 21:55:26 -05:00
B = null
makeClass = ->
B = class extends this
[CS2] Compile all super calls to ES2015 super (#4424) * Compile all super calls to ES2015 super This breaks using `super` in non-methods, meaning several tests are failing. Self-compilation still works. * Use bound functions for IIFEs containing `super` `super` can only be called directly in a method, or in an arrow function. * Fix handling of `class @A extends A` This behaviour worked 'for free' when the parent reference was being cached by the executable class body wrapper. There now needs to be special handling in place to check if the parent name matches the class name, and if so to cache the parent reference. * Fix tests broken by compiling ES2015 `super` * Disallow bare super This removes syntax support for 'bare' super calls, e.g.: class B extends A constructor: -> super `super` must now always be followed with arguments like a regular function call. This also removes the capability of implicitly forwarding arguments. The above can be equivalently be written as: class B extends A constructor: -> super arguments... * Support super with accessors `super` with following accessor(s) is now compiled to ES2015 equivalents. In particular, expressions such as `super.name`, `super[name]`, and also `super.name.prop` are all now valid, and can be used as expected as calls (i.e. `super.name()`) or in expressions (i.e. `if super.name? ...`). `super` without accessors is compiled to a constructor super call in a constructor, and otherwise, as before, to a super call to the method of the same name, i.e. speak: -> super() ...is equivalent to speak: -> super.speak() A neat side-effect of the changes is that existential calls now work properly with super, meaning `super?()` will only call if the super property exists (and is a function). This is not valid for super in constructors. * Prevent calling `super` methods with `new` This fixes a bug in the previous super handling whereby using the `new` operator with a `super` call would silently drop the `new`. This is now an explicit compiler error, as it is invalid JS at runtime. * Clean up some old super handling code This was mostly code for tracking the source classes and variables for methods, which were needed to build the old lookups on `__super__`. * Add TODO to improve bare super parse error * Add some TODOs to improve some of the class tests
2017-02-04 15:03:17 -05:00
func: -> super() + ' B'
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makeClass.call A
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2011-03-11 21:55:26 -05:00
eq (new B()).func(), 'A B'
2010-12-29 00:48:54 -05:00
2011-03-11 21:55:26 -05:00
test "ensure that constructors invoked with splats return a new object", ->
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2011-03-11 21:55:26 -05:00
args = [1, 2, 3]
Type = (@args) ->
type = new Type args
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ok type and type instanceof Type
ok type.args and type.args instanceof Array
ok v is args[i] for v, i in type.args
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Type1 = (@a, @b, @c) ->
type1 = new Type1 args...
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ok type1 instanceof Type1
eq type1.constructor, Type1
ok type1.a is args[0] and type1.b is args[1] and type1.c is args[2]
2010-12-30 22:48:31 -05:00
2011-03-11 21:55:26 -05:00
# Ensure that constructors invoked with splats cache the function.
called = 0
get = -> if called++ then false else class Type
[CS2] Compile class constructors to ES2015 classes (#4354) * Compile classes to ES2015 classes Rather than compiling classes to named functions with prototype and class assignments, they are now compiled to ES2015 class declarations. Backwards compatibility has been maintained by compiling ES2015- incompatible properties as prototype or class assignments. `super` continues to be compiled as before. Where possible, classes will be compiled "bare", without an enclosing IIFE. This is possible when the class contains only ES2015 compatible expressions (methods and static methods), and has no parent (this last constraint is a result of the legacy `super` compilation, and could be removed once ES2015 `super` is being used). Classes are still assigned to variables to maintain compatibility for assigned class expressions. There are a few changes to existing functionality that could break backwards compatibility: - Derived constructors that deliberately don't call `super` are no longer possible. ES2015 derived classes can't use `this` unless the parent constructor has been called, so it's now called implicitly when not present. - As a consequence of the above, derived constructors with @ parameters or bound methods and explicit `super` calls are not allowed. The implicit `super` must be used in these cases. * Add tests to verify class interoperability with ES * Refactor class nodes to separate executable body logic Logic has been redistributed amongst the class nodes so that: - `Class` contains the logic necessary to compile an ES class declaration. - `ExecutableClassBody` contains the logic necessary to compile CS' class extensions that require an executable class body. `Class` still necessarily contains logic to determine whether an expression is valid in an ES class initializer or not. If any invalid expressions are found then `Class` will wrap itself in an `ExecutableClassBody` when compiling. * Rename `Code#static` to `Code#isStatic` This naming is more consistent with other `Code` flags. * Output anonymous classes when possible Anonymous classes can be output when: - The class has no parent. The current super compilation needs a class variable to reference. This condition will go away when ES2015 super is in use. - The class contains no bound static methods. Bound static methods have their context set to the class name. * Throw errors at compile time for async or generator constructors * Improve handling of anonymous classes Anonymous classes are now always anonymous. If a name is required (e.g. for bound static methods or derived classes) then the class is compiled in an `ExecutableClassBody` which will give the anonymous class a stable reference. * Add a `replaceInContext` method to `Node` `replaceInContext` will traverse children looking for a node for which `match` returns true. Once found, the matching node will be replaced by the result of calling `replacement`. * Separate `this` assignments from function parameters This change has been made to simplify two future changes: 1. Outputting `@`-param assignments after a `super` call. In this case it is necessary that non-`@` parameters are available before `super` is called, so destructuring has to happen before `this` assignment. 2. Compiling destructured assignment to ES6 In this case also destructuring has to happen before `this`, as destructuring can happen in the arguments list, but `this` assignment can not. A bonus side-effect is that default values for `@` params are now output as ES6 default parameters, e.g. (@a = 1) -> becomes function a (a = 1) { this.a = a; } * Change `super` handling in class constructors Inside an ES derived constructor (a constructor for a class that extends another class), it is impossible to access `this` until `super` has been called. This conflicts with CoffeeScript's `@`-param and bound method features, which compile to `this` references at the top of a function body. For example: class B extends A constructor: (@param) -> super method: => This would compile to something like: class B extends A { constructor (param) { this.param = param; this.method = bind(this.method, this); super(...arguments); } } This would break in an ES-compliant runtime as there are `this` references before the call to `super`. Before this commit we were dealing with this by injecting an implicit `super` call into derived constructors that do not already have an explicit `super` call. Furthermore, we would disallow explicit `super` calls in derived constructors that used bound methods or `@`-params, meaning the above example would need to be rewritten as: class B extends A constructor: (@param) -> method: => This would result in a call to `super(...arguments)` being generated as the first expression in `B#constructor`. Whilst this approach seems to work pretty well, and is arguably more convenient than having to manually call `super` when you don't particularly care about the arguments, it does introduce some 'magic' and separation from ES, and would likely be a pain point in a project that made use of significant constructor overriding. This commit introduces a mechanism through which `super` in constructors is 'expanded' to include any generated `this` assignments, whilst retaining the same semantics of a super call. The first example above now compiles to something like: class B extends A { constructor (param) { var ref ref = super(...arguments), this.param = param, this.method = bind(this.method, this), ref; } } * Improve `super` handling in constructors Rather than functions expanding their `super` calls, the `SuperCall` node can now be given a list of `thisAssignments` to apply when it is compiled. This allows us to use the normal compiler machinery to determine whether the `super` result needs to be cached, whether it appears inline or not, etc. * Fix anonymous classes at the top level Anonymous classes in ES are only valid within expressions. If an anonymous class is at the top level it will now be wrapped in parenthses to force it into an expression. * Re-add Parens wrapper around executable class bodies This was lost in the refactoring, but it necessary to ensure `new class ...` works as expected when there's an executable body. * Throw compiler errors for badly configured derived constructors Rather than letting them become runtime errors, the following checks are now performed when compiling a derived constructor: - The constructor **must** include a call to `super`. - The constructor **must not** reference `this` in the function body before `super` has been called. * Add some tests exercising new class behaviour - async methods in classes - `this` access after `super` in extended classes - constructor super in arrow functions - constructor functions can't be async - constructor functions can't be generators - derived constructors must call super - derived constructors can't reference `this` before calling super - generator methods in classes - 'new' target * Improve constructor `super` errors Add a check for `super` in non-extended class constructors, and explicitly mention derived constructors in the "can't reference this before super" error. * Fix compilation of multiple `super` paths in derived constructors `super` can only be called once, but it can be called conditionally from multiple locations. The chosen fix is to add the `this` assignments to every super call. * Additional class tests, added as a separate file to simplify testing and merging. Some methods are commented out because they currently throw and I'm not sure how to test for compilation errors like those. There is also one test which I deliberately left without passing, `super` in an external prototype override. This test should 'pass' but is really a variation on the failing `super only allowed in an instance method` tests above it. * Changes to the tests. Found bug in super in prototype method. fixed. * Added failing test back in, dealing with bound functions in external prototype overrides. * Located a bug in the compiler relating to assertions and escaped ES6 classes. * Move tests from classes-additional.coffee into classes.coffee; comment out console.log * Cleaned up tests and made changes based on feedback. Test at the end still has issues, but it's commented out for now. * Make HoistTarget.expand recursive It's possible that a hoisted node may itself contain hoisted nodes (e.g. a class method inside a class method). For this to work the hoisted fragments need to be expanded recursively. * Uncomment final test in classes.coffee The test case now compiles, however another issue is affecting the test due to the error for `this` before `super` triggering based on source order rather than execution order. These have been commented out for now. * Fixed last test TODOs in test/classes.coffee Turns out an expression like `this.foo = super()` won't run in JS as it attempts to lookup `this` before evaluating `super` (i.e. throws "this is not defined"). * Added more tests for compatability checks, statics, prototypes and ES6 expectations. Cleaned test "nested classes with super". * Changes to reflect feedback and to comment out issues that will be addressed seperately. * Clean up test/classes.coffee - Trim trailing whitespace. - Rephrase a condition to be more idiomatic. * Remove check for `super` in derived constructors In order to be usable at runtime, an extended ES class must call `super` OR return an alternative object. This check prevented the latter case, and checking for an alternative return can't be completed statically without control flow analysis. * Disallow 'super' in constructor parameter defaults There are many edge cases when combining 'super' in parameter defaults with @-parameters and bound functions (and potentially property initializers in the future). Rather than attempting to resolve these edge cases, 'super' is now explicitly disallowed in constructor parameter defaults. * Disallow @-params in derived constructors without 'super' @-parameters can't be assigned unless 'super' is called.
2017-01-13 00:55:30 -05:00
new (get()) args...
2010-12-30 22:48:31 -05:00
2011-03-11 21:55:26 -05:00
test "`new` shouldn't add extra parens", ->
2010-12-30 22:48:31 -05:00
2011-03-11 21:55:26 -05:00
ok new Date().constructor is Date
2010-12-30 22:48:31 -05:00
2011-03-11 21:55:26 -05:00
test "`new` works against bare function", ->
eq Date, new ->
Date
test "`new` works against statement", ->
class A
(new try A) instanceof A
test "#1182: a subclass should be able to set its constructor to an external function", ->
ctor = ->
@val = 1
[CS2] Compile class constructors to ES2015 classes (#4354) * Compile classes to ES2015 classes Rather than compiling classes to named functions with prototype and class assignments, they are now compiled to ES2015 class declarations. Backwards compatibility has been maintained by compiling ES2015- incompatible properties as prototype or class assignments. `super` continues to be compiled as before. Where possible, classes will be compiled "bare", without an enclosing IIFE. This is possible when the class contains only ES2015 compatible expressions (methods and static methods), and has no parent (this last constraint is a result of the legacy `super` compilation, and could be removed once ES2015 `super` is being used). Classes are still assigned to variables to maintain compatibility for assigned class expressions. There are a few changes to existing functionality that could break backwards compatibility: - Derived constructors that deliberately don't call `super` are no longer possible. ES2015 derived classes can't use `this` unless the parent constructor has been called, so it's now called implicitly when not present. - As a consequence of the above, derived constructors with @ parameters or bound methods and explicit `super` calls are not allowed. The implicit `super` must be used in these cases. * Add tests to verify class interoperability with ES * Refactor class nodes to separate executable body logic Logic has been redistributed amongst the class nodes so that: - `Class` contains the logic necessary to compile an ES class declaration. - `ExecutableClassBody` contains the logic necessary to compile CS' class extensions that require an executable class body. `Class` still necessarily contains logic to determine whether an expression is valid in an ES class initializer or not. If any invalid expressions are found then `Class` will wrap itself in an `ExecutableClassBody` when compiling. * Rename `Code#static` to `Code#isStatic` This naming is more consistent with other `Code` flags. * Output anonymous classes when possible Anonymous classes can be output when: - The class has no parent. The current super compilation needs a class variable to reference. This condition will go away when ES2015 super is in use. - The class contains no bound static methods. Bound static methods have their context set to the class name. * Throw errors at compile time for async or generator constructors * Improve handling of anonymous classes Anonymous classes are now always anonymous. If a name is required (e.g. for bound static methods or derived classes) then the class is compiled in an `ExecutableClassBody` which will give the anonymous class a stable reference. * Add a `replaceInContext` method to `Node` `replaceInContext` will traverse children looking for a node for which `match` returns true. Once found, the matching node will be replaced by the result of calling `replacement`. * Separate `this` assignments from function parameters This change has been made to simplify two future changes: 1. Outputting `@`-param assignments after a `super` call. In this case it is necessary that non-`@` parameters are available before `super` is called, so destructuring has to happen before `this` assignment. 2. Compiling destructured assignment to ES6 In this case also destructuring has to happen before `this`, as destructuring can happen in the arguments list, but `this` assignment can not. A bonus side-effect is that default values for `@` params are now output as ES6 default parameters, e.g. (@a = 1) -> becomes function a (a = 1) { this.a = a; } * Change `super` handling in class constructors Inside an ES derived constructor (a constructor for a class that extends another class), it is impossible to access `this` until `super` has been called. This conflicts with CoffeeScript's `@`-param and bound method features, which compile to `this` references at the top of a function body. For example: class B extends A constructor: (@param) -> super method: => This would compile to something like: class B extends A { constructor (param) { this.param = param; this.method = bind(this.method, this); super(...arguments); } } This would break in an ES-compliant runtime as there are `this` references before the call to `super`. Before this commit we were dealing with this by injecting an implicit `super` call into derived constructors that do not already have an explicit `super` call. Furthermore, we would disallow explicit `super` calls in derived constructors that used bound methods or `@`-params, meaning the above example would need to be rewritten as: class B extends A constructor: (@param) -> method: => This would result in a call to `super(...arguments)` being generated as the first expression in `B#constructor`. Whilst this approach seems to work pretty well, and is arguably more convenient than having to manually call `super` when you don't particularly care about the arguments, it does introduce some 'magic' and separation from ES, and would likely be a pain point in a project that made use of significant constructor overriding. This commit introduces a mechanism through which `super` in constructors is 'expanded' to include any generated `this` assignments, whilst retaining the same semantics of a super call. The first example above now compiles to something like: class B extends A { constructor (param) { var ref ref = super(...arguments), this.param = param, this.method = bind(this.method, this), ref; } } * Improve `super` handling in constructors Rather than functions expanding their `super` calls, the `SuperCall` node can now be given a list of `thisAssignments` to apply when it is compiled. This allows us to use the normal compiler machinery to determine whether the `super` result needs to be cached, whether it appears inline or not, etc. * Fix anonymous classes at the top level Anonymous classes in ES are only valid within expressions. If an anonymous class is at the top level it will now be wrapped in parenthses to force it into an expression. * Re-add Parens wrapper around executable class bodies This was lost in the refactoring, but it necessary to ensure `new class ...` works as expected when there's an executable body. * Throw compiler errors for badly configured derived constructors Rather than letting them become runtime errors, the following checks are now performed when compiling a derived constructor: - The constructor **must** include a call to `super`. - The constructor **must not** reference `this` in the function body before `super` has been called. * Add some tests exercising new class behaviour - async methods in classes - `this` access after `super` in extended classes - constructor super in arrow functions - constructor functions can't be async - constructor functions can't be generators - derived constructors must call super - derived constructors can't reference `this` before calling super - generator methods in classes - 'new' target * Improve constructor `super` errors Add a check for `super` in non-extended class constructors, and explicitly mention derived constructors in the "can't reference this before super" error. * Fix compilation of multiple `super` paths in derived constructors `super` can only be called once, but it can be called conditionally from multiple locations. The chosen fix is to add the `this` assignments to every super call. * Additional class tests, added as a separate file to simplify testing and merging. Some methods are commented out because they currently throw and I'm not sure how to test for compilation errors like those. There is also one test which I deliberately left without passing, `super` in an external prototype override. This test should 'pass' but is really a variation on the failing `super only allowed in an instance method` tests above it. * Changes to the tests. Found bug in super in prototype method. fixed. * Added failing test back in, dealing with bound functions in external prototype overrides. * Located a bug in the compiler relating to assertions and escaped ES6 classes. * Move tests from classes-additional.coffee into classes.coffee; comment out console.log * Cleaned up tests and made changes based on feedback. Test at the end still has issues, but it's commented out for now. * Make HoistTarget.expand recursive It's possible that a hoisted node may itself contain hoisted nodes (e.g. a class method inside a class method). For this to work the hoisted fragments need to be expanded recursively. * Uncomment final test in classes.coffee The test case now compiles, however another issue is affecting the test due to the error for `this` before `super` triggering based on source order rather than execution order. These have been commented out for now. * Fixed last test TODOs in test/classes.coffee Turns out an expression like `this.foo = super()` won't run in JS as it attempts to lookup `this` before evaluating `super` (i.e. throws "this is not defined"). * Added more tests for compatability checks, statics, prototypes and ES6 expectations. Cleaned test "nested classes with super". * Changes to reflect feedback and to comment out issues that will be addressed seperately. * Clean up test/classes.coffee - Trim trailing whitespace. - Rephrase a condition to be more idiomatic. * Remove check for `super` in derived constructors In order to be usable at runtime, an extended ES class must call `super` OR return an alternative object. This check prevented the latter case, and checking for an alternative return can't be completed statically without control flow analysis. * Disallow 'super' in constructor parameter defaults There are many edge cases when combining 'super' in parameter defaults with @-parameters and bound functions (and potentially property initializers in the future). Rather than attempting to resolve these edge cases, 'super' is now explicitly disallowed in constructor parameter defaults. * Disallow @-params in derived constructors without 'super' @-parameters can't be assigned unless 'super' is called.
2017-01-13 00:55:30 -05:00
return
class A
class B extends A
constructor: ctor
eq (new B).val, 1
test "#1182: external constructors continued", ->
ctor = ->
class A
class B extends A
method: ->
constructor: ctor
ok B::method
test "#1313: misplaced __extends", ->
nonce = {}
class A
class B extends A
prop: nonce
[CS2] Compile all super calls to ES2015 super (#4424) * Compile all super calls to ES2015 super This breaks using `super` in non-methods, meaning several tests are failing. Self-compilation still works. * Use bound functions for IIFEs containing `super` `super` can only be called directly in a method, or in an arrow function. * Fix handling of `class @A extends A` This behaviour worked 'for free' when the parent reference was being cached by the executable class body wrapper. There now needs to be special handling in place to check if the parent name matches the class name, and if so to cache the parent reference. * Fix tests broken by compiling ES2015 `super` * Disallow bare super This removes syntax support for 'bare' super calls, e.g.: class B extends A constructor: -> super `super` must now always be followed with arguments like a regular function call. This also removes the capability of implicitly forwarding arguments. The above can be equivalently be written as: class B extends A constructor: -> super arguments... * Support super with accessors `super` with following accessor(s) is now compiled to ES2015 equivalents. In particular, expressions such as `super.name`, `super[name]`, and also `super.name.prop` are all now valid, and can be used as expected as calls (i.e. `super.name()`) or in expressions (i.e. `if super.name? ...`). `super` without accessors is compiled to a constructor super call in a constructor, and otherwise, as before, to a super call to the method of the same name, i.e. speak: -> super() ...is equivalent to speak: -> super.speak() A neat side-effect of the changes is that existential calls now work properly with super, meaning `super?()` will only call if the super property exists (and is a function). This is not valid for super in constructors. * Prevent calling `super` methods with `new` This fixes a bug in the previous super handling whereby using the `new` operator with a `super` call would silently drop the `new`. This is now an explicit compiler error, as it is invalid JS at runtime. * Clean up some old super handling code This was mostly code for tracking the source classes and variables for methods, which were needed to build the old lookups on `__super__`. * Add TODO to improve bare super parse error * Add some TODOs to improve some of the class tests
2017-02-04 15:03:17 -05:00
constructor: -> super()
eq nonce, B::prop
test "#1182: execution order needs to be considered as well", ->
counter = 0
makeFn = (n) -> eq n, ++counter; ->
class B extends (makeFn 1)
@B: makeFn 2
constructor: makeFn 3
test "#1182: external constructors with bound functions", ->
fn = ->
{one: 1}
this
class B
class A
constructor: fn
method: => this instanceof A
ok (new A).method.call(new B)
test "#1372: bound class methods with reserved names", ->
class C
delete: =>
ok C::delete
2011-05-25 03:22:06 -04:00
test "#1380: `super` with reserved names", ->
class C
[CS2] Compile all super calls to ES2015 super (#4424) * Compile all super calls to ES2015 super This breaks using `super` in non-methods, meaning several tests are failing. Self-compilation still works. * Use bound functions for IIFEs containing `super` `super` can only be called directly in a method, or in an arrow function. * Fix handling of `class @A extends A` This behaviour worked 'for free' when the parent reference was being cached by the executable class body wrapper. There now needs to be special handling in place to check if the parent name matches the class name, and if so to cache the parent reference. * Fix tests broken by compiling ES2015 `super` * Disallow bare super This removes syntax support for 'bare' super calls, e.g.: class B extends A constructor: -> super `super` must now always be followed with arguments like a regular function call. This also removes the capability of implicitly forwarding arguments. The above can be equivalently be written as: class B extends A constructor: -> super arguments... * Support super with accessors `super` with following accessor(s) is now compiled to ES2015 equivalents. In particular, expressions such as `super.name`, `super[name]`, and also `super.name.prop` are all now valid, and can be used as expected as calls (i.e. `super.name()`) or in expressions (i.e. `if super.name? ...`). `super` without accessors is compiled to a constructor super call in a constructor, and otherwise, as before, to a super call to the method of the same name, i.e. speak: -> super() ...is equivalent to speak: -> super.speak() A neat side-effect of the changes is that existential calls now work properly with super, meaning `super?()` will only call if the super property exists (and is a function). This is not valid for super in constructors. * Prevent calling `super` methods with `new` This fixes a bug in the previous super handling whereby using the `new` operator with a `super` call would silently drop the `new`. This is now an explicit compiler error, as it is invalid JS at runtime. * Clean up some old super handling code This was mostly code for tracking the source classes and variables for methods, which were needed to build the old lookups on `__super__`. * Add TODO to improve bare super parse error * Add some TODOs to improve some of the class tests
2017-02-04 15:03:17 -05:00
do: -> super()
2011-05-25 03:22:06 -04:00
ok C::do
class B
[CS2] Compile all super calls to ES2015 super (#4424) * Compile all super calls to ES2015 super This breaks using `super` in non-methods, meaning several tests are failing. Self-compilation still works. * Use bound functions for IIFEs containing `super` `super` can only be called directly in a method, or in an arrow function. * Fix handling of `class @A extends A` This behaviour worked 'for free' when the parent reference was being cached by the executable class body wrapper. There now needs to be special handling in place to check if the parent name matches the class name, and if so to cache the parent reference. * Fix tests broken by compiling ES2015 `super` * Disallow bare super This removes syntax support for 'bare' super calls, e.g.: class B extends A constructor: -> super `super` must now always be followed with arguments like a regular function call. This also removes the capability of implicitly forwarding arguments. The above can be equivalently be written as: class B extends A constructor: -> super arguments... * Support super with accessors `super` with following accessor(s) is now compiled to ES2015 equivalents. In particular, expressions such as `super.name`, `super[name]`, and also `super.name.prop` are all now valid, and can be used as expected as calls (i.e. `super.name()`) or in expressions (i.e. `if super.name? ...`). `super` without accessors is compiled to a constructor super call in a constructor, and otherwise, as before, to a super call to the method of the same name, i.e. speak: -> super() ...is equivalent to speak: -> super.speak() A neat side-effect of the changes is that existential calls now work properly with super, meaning `super?()` will only call if the super property exists (and is a function). This is not valid for super in constructors. * Prevent calling `super` methods with `new` This fixes a bug in the previous super handling whereby using the `new` operator with a `super` call would silently drop the `new`. This is now an explicit compiler error, as it is invalid JS at runtime. * Clean up some old super handling code This was mostly code for tracking the source classes and variables for methods, which were needed to build the old lookups on `__super__`. * Add TODO to improve bare super parse error * Add some TODOs to improve some of the class tests
2017-02-04 15:03:17 -05:00
0: -> super()
ok B::[0]
test "#1464: bound class methods should keep context", ->
nonce = {}
nonce2 = {}
class C
constructor: (@id) ->
@boundStaticColon: => new this(nonce)
@boundStaticEqual= => new this(nonce2)
eq nonce, C.boundStaticColon().id
eq nonce2, C.boundStaticEqual().id
test "#1009: classes with reserved words as determined names", -> (->
eq 'function', typeof (class @for)
ok not /\beval\b/.test (class @eval).toString()
ok not /\barguments\b/.test (class @arguments).toString()
).call {}
test "#1482: classes can extend expressions", ->
id = (x) -> x
nonce = {}
class A then nonce: nonce
class B extends id A
eq nonce, (new B).nonce
test "#1598: super works for static methods too", ->
class Parent
method: ->
'NO'
@method: ->
'yes'
class Child extends Parent
@method: ->
[CS2] Compile all super calls to ES2015 super (#4424) * Compile all super calls to ES2015 super This breaks using `super` in non-methods, meaning several tests are failing. Self-compilation still works. * Use bound functions for IIFEs containing `super` `super` can only be called directly in a method, or in an arrow function. * Fix handling of `class @A extends A` This behaviour worked 'for free' when the parent reference was being cached by the executable class body wrapper. There now needs to be special handling in place to check if the parent name matches the class name, and if so to cache the parent reference. * Fix tests broken by compiling ES2015 `super` * Disallow bare super This removes syntax support for 'bare' super calls, e.g.: class B extends A constructor: -> super `super` must now always be followed with arguments like a regular function call. This also removes the capability of implicitly forwarding arguments. The above can be equivalently be written as: class B extends A constructor: -> super arguments... * Support super with accessors `super` with following accessor(s) is now compiled to ES2015 equivalents. In particular, expressions such as `super.name`, `super[name]`, and also `super.name.prop` are all now valid, and can be used as expected as calls (i.e. `super.name()`) or in expressions (i.e. `if super.name? ...`). `super` without accessors is compiled to a constructor super call in a constructor, and otherwise, as before, to a super call to the method of the same name, i.e. speak: -> super() ...is equivalent to speak: -> super.speak() A neat side-effect of the changes is that existential calls now work properly with super, meaning `super?()` will only call if the super property exists (and is a function). This is not valid for super in constructors. * Prevent calling `super` methods with `new` This fixes a bug in the previous super handling whereby using the `new` operator with a `super` call would silently drop the `new`. This is now an explicit compiler error, as it is invalid JS at runtime. * Clean up some old super handling code This was mostly code for tracking the source classes and variables for methods, which were needed to build the old lookups on `__super__`. * Add TODO to improve bare super parse error * Add some TODOs to improve some of the class tests
2017-02-04 15:03:17 -05:00
'pass? ' + super()
eq Child.method(), 'pass? yes'
2011-12-24 07:04:34 -05:00
2011-12-14 11:02:10 -05:00
test "#1842: Regression with bound functions within bound class methods", ->
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2011-12-14 11:02:10 -05:00
class Store
@bound: =>
do =>
eq this, Store
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2011-12-14 11:02:10 -05:00
Store.bound()
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# And a fancier case:
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class Store
2011-12-24 07:04:34 -05:00
eq this, Store
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@bound: =>
do =>
eq this, Store
2011-12-24 07:04:34 -05:00
@unbound: ->
eq this, Store
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instance: =>
ok this instanceof Store
2011-12-24 07:04:34 -05:00
Store.bound()
Store.unbound()
2011-12-14 12:17:21 -05:00
(new Store).instance()
2011-12-24 07:04:34 -05:00
2011-12-14 12:17:21 -05:00
test "#1876: Class @A extends A", ->
class A
class @A extends A
2011-12-24 07:04:34 -05:00
2011-12-14 12:17:21 -05:00
ok (new @A) instanceof A
2011-12-24 07:04:34 -05:00
2011-12-15 16:03:01 -05:00
test "#1813: Passing class definitions as expressions", ->
ident = (x) -> x
2011-12-24 07:04:34 -05:00
2011-12-15 16:03:01 -05:00
result = ident class A then x = 1
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2011-12-15 16:03:01 -05:00
eq result, A
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2011-12-15 16:03:01 -05:00
result = ident class B extends A
x = 1
2011-12-24 07:04:34 -05:00
2011-12-15 16:03:01 -05:00
eq result, B
2011-12-24 07:04:34 -05:00
2013-02-28 08:37:30 -05:00
test "#1966: external constructors should produce their return value", ->
ctor = -> {}
class A then constructor: ctor
ok (new A) not instanceof A
2011-12-27 19:54:14 -05:00
test "#1980: regression with an inherited class with static function members", ->
2011-12-27 19:54:14 -05:00
class A
class B extends A
@static: => 'value'
2012-01-12 18:34:50 -05:00
eq B.static(), 'value'
2012-01-12 18:34:50 -05:00
test "#1534: class then 'use strict'", ->
# [14.1 Directive Prologues and the Use Strict Directive](http://es5.github.com/#x14.1)
2012-01-12 18:34:50 -05:00
nonce = {}
error = 'do -> ok this'
strictTest = "do ->'use strict';#{error}"
return unless (try CoffeeScript.run strictTest, bare: yes catch e then nonce) is nonce
throws -> CoffeeScript.run "class then 'use strict';#{error}", bare: yes
doesNotThrow -> CoffeeScript.run "class then #{error}", bare: yes
doesNotThrow -> CoffeeScript.run "class then #{error};'use strict'", bare: yes
# comments are ignored in the Directive Prologue
comments = ["""
class
### comment ###
'use strict'
#{error}""",
"""
class
### comment 1 ###
### comment 2 ###
'use strict'
#{error}""",
"""
class
### comment 1 ###
### comment 2 ###
'use strict'
#{error}
### comment 3 ###"""
]
throws (-> CoffeeScript.run comment, bare: yes) for comment in comments
# [ES5 §14.1](http://es5.github.com/#x14.1) allows for other directives
directives = ["""
class
'directive 1'
'use strict'
#{error}""",
"""
class
'use strict'
'directive 2'
#{error}""",
"""
class
### comment 1 ###
'directive 1'
'use strict'
#{error}""",
"""
class
### comment 1 ###
'directive 1'
### comment 2 ###
'use strict'
#{error}"""
]
throws (-> CoffeeScript.run directive, bare: yes) for directive in directives
test "#2052: classes should work in strict mode", ->
try
do ->
'use strict'
class A
catch e
ok no
test "directives in class with extends ", ->
strictTest = """
class extends Object
### comment ###
'use strict'
do -> eq this, undefined
"""
CoffeeScript.run strictTest, bare: yes
test "#2630: class bodies can't reference arguments", ->
throwsCompileError 'class Test then arguments'
# #4320: Don't be too eager when checking, though.
class Test
arguments: 5
eq 5, Test::arguments
test "#2319: fn class n extends o.p [INDENT] x = 123", ->
first = ->
base = onebase: ->
first class OneKeeper extends base.onebase
one = 1
one: -> one
2013-02-28 08:37:30 -05:00
eq new OneKeeper().one(), 1
test "#2599: other typed constructors should be inherited", ->
class Base
constructor: -> return {}
class Derived extends Base
ok (new Derived) not instanceof Derived
ok (new Derived) not instanceof Base
ok (new Base) not instanceof Base
[CS2] Compile class constructors to ES2015 classes (#4354) * Compile classes to ES2015 classes Rather than compiling classes to named functions with prototype and class assignments, they are now compiled to ES2015 class declarations. Backwards compatibility has been maintained by compiling ES2015- incompatible properties as prototype or class assignments. `super` continues to be compiled as before. Where possible, classes will be compiled "bare", without an enclosing IIFE. This is possible when the class contains only ES2015 compatible expressions (methods and static methods), and has no parent (this last constraint is a result of the legacy `super` compilation, and could be removed once ES2015 `super` is being used). Classes are still assigned to variables to maintain compatibility for assigned class expressions. There are a few changes to existing functionality that could break backwards compatibility: - Derived constructors that deliberately don't call `super` are no longer possible. ES2015 derived classes can't use `this` unless the parent constructor has been called, so it's now called implicitly when not present. - As a consequence of the above, derived constructors with @ parameters or bound methods and explicit `super` calls are not allowed. The implicit `super` must be used in these cases. * Add tests to verify class interoperability with ES * Refactor class nodes to separate executable body logic Logic has been redistributed amongst the class nodes so that: - `Class` contains the logic necessary to compile an ES class declaration. - `ExecutableClassBody` contains the logic necessary to compile CS' class extensions that require an executable class body. `Class` still necessarily contains logic to determine whether an expression is valid in an ES class initializer or not. If any invalid expressions are found then `Class` will wrap itself in an `ExecutableClassBody` when compiling. * Rename `Code#static` to `Code#isStatic` This naming is more consistent with other `Code` flags. * Output anonymous classes when possible Anonymous classes can be output when: - The class has no parent. The current super compilation needs a class variable to reference. This condition will go away when ES2015 super is in use. - The class contains no bound static methods. Bound static methods have their context set to the class name. * Throw errors at compile time for async or generator constructors * Improve handling of anonymous classes Anonymous classes are now always anonymous. If a name is required (e.g. for bound static methods or derived classes) then the class is compiled in an `ExecutableClassBody` which will give the anonymous class a stable reference. * Add a `replaceInContext` method to `Node` `replaceInContext` will traverse children looking for a node for which `match` returns true. Once found, the matching node will be replaced by the result of calling `replacement`. * Separate `this` assignments from function parameters This change has been made to simplify two future changes: 1. Outputting `@`-param assignments after a `super` call. In this case it is necessary that non-`@` parameters are available before `super` is called, so destructuring has to happen before `this` assignment. 2. Compiling destructured assignment to ES6 In this case also destructuring has to happen before `this`, as destructuring can happen in the arguments list, but `this` assignment can not. A bonus side-effect is that default values for `@` params are now output as ES6 default parameters, e.g. (@a = 1) -> becomes function a (a = 1) { this.a = a; } * Change `super` handling in class constructors Inside an ES derived constructor (a constructor for a class that extends another class), it is impossible to access `this` until `super` has been called. This conflicts with CoffeeScript's `@`-param and bound method features, which compile to `this` references at the top of a function body. For example: class B extends A constructor: (@param) -> super method: => This would compile to something like: class B extends A { constructor (param) { this.param = param; this.method = bind(this.method, this); super(...arguments); } } This would break in an ES-compliant runtime as there are `this` references before the call to `super`. Before this commit we were dealing with this by injecting an implicit `super` call into derived constructors that do not already have an explicit `super` call. Furthermore, we would disallow explicit `super` calls in derived constructors that used bound methods or `@`-params, meaning the above example would need to be rewritten as: class B extends A constructor: (@param) -> method: => This would result in a call to `super(...arguments)` being generated as the first expression in `B#constructor`. Whilst this approach seems to work pretty well, and is arguably more convenient than having to manually call `super` when you don't particularly care about the arguments, it does introduce some 'magic' and separation from ES, and would likely be a pain point in a project that made use of significant constructor overriding. This commit introduces a mechanism through which `super` in constructors is 'expanded' to include any generated `this` assignments, whilst retaining the same semantics of a super call. The first example above now compiles to something like: class B extends A { constructor (param) { var ref ref = super(...arguments), this.param = param, this.method = bind(this.method, this), ref; } } * Improve `super` handling in constructors Rather than functions expanding their `super` calls, the `SuperCall` node can now be given a list of `thisAssignments` to apply when it is compiled. This allows us to use the normal compiler machinery to determine whether the `super` result needs to be cached, whether it appears inline or not, etc. * Fix anonymous classes at the top level Anonymous classes in ES are only valid within expressions. If an anonymous class is at the top level it will now be wrapped in parenthses to force it into an expression. * Re-add Parens wrapper around executable class bodies This was lost in the refactoring, but it necessary to ensure `new class ...` works as expected when there's an executable body. * Throw compiler errors for badly configured derived constructors Rather than letting them become runtime errors, the following checks are now performed when compiling a derived constructor: - The constructor **must** include a call to `super`. - The constructor **must not** reference `this` in the function body before `super` has been called. * Add some tests exercising new class behaviour - async methods in classes - `this` access after `super` in extended classes - constructor super in arrow functions - constructor functions can't be async - constructor functions can't be generators - derived constructors must call super - derived constructors can't reference `this` before calling super - generator methods in classes - 'new' target * Improve constructor `super` errors Add a check for `super` in non-extended class constructors, and explicitly mention derived constructors in the "can't reference this before super" error. * Fix compilation of multiple `super` paths in derived constructors `super` can only be called once, but it can be called conditionally from multiple locations. The chosen fix is to add the `this` assignments to every super call. * Additional class tests, added as a separate file to simplify testing and merging. Some methods are commented out because they currently throw and I'm not sure how to test for compilation errors like those. There is also one test which I deliberately left without passing, `super` in an external prototype override. This test should 'pass' but is really a variation on the failing `super only allowed in an instance method` tests above it. * Changes to the tests. Found bug in super in prototype method. fixed. * Added failing test back in, dealing with bound functions in external prototype overrides. * Located a bug in the compiler relating to assertions and escaped ES6 classes. * Move tests from classes-additional.coffee into classes.coffee; comment out console.log * Cleaned up tests and made changes based on feedback. Test at the end still has issues, but it's commented out for now. * Make HoistTarget.expand recursive It's possible that a hoisted node may itself contain hoisted nodes (e.g. a class method inside a class method). For this to work the hoisted fragments need to be expanded recursively. * Uncomment final test in classes.coffee The test case now compiles, however another issue is affecting the test due to the error for `this` before `super` triggering based on source order rather than execution order. These have been commented out for now. * Fixed last test TODOs in test/classes.coffee Turns out an expression like `this.foo = super()` won't run in JS as it attempts to lookup `this` before evaluating `super` (i.e. throws "this is not defined"). * Added more tests for compatability checks, statics, prototypes and ES6 expectations. Cleaned test "nested classes with super". * Changes to reflect feedback and to comment out issues that will be addressed seperately. * Clean up test/classes.coffee - Trim trailing whitespace. - Rephrase a condition to be more idiomatic. * Remove check for `super` in derived constructors In order to be usable at runtime, an extended ES class must call `super` OR return an alternative object. This check prevented the latter case, and checking for an alternative return can't be completed statically without control flow analysis. * Disallow 'super' in constructor parameter defaults There are many edge cases when combining 'super' in parameter defaults with @-parameters and bound functions (and potentially property initializers in the future). Rather than attempting to resolve these edge cases, 'super' is now explicitly disallowed in constructor parameter defaults. * Disallow @-params in derived constructors without 'super' @-parameters can't be assigned unless 'super' is called.
2017-01-13 00:55:30 -05:00
test "extending native objects works with and without defining a constructor", ->
class MyArray extends Array
method: -> 'yes!'
[CS2] Compile class constructors to ES2015 classes (#4354) * Compile classes to ES2015 classes Rather than compiling classes to named functions with prototype and class assignments, they are now compiled to ES2015 class declarations. Backwards compatibility has been maintained by compiling ES2015- incompatible properties as prototype or class assignments. `super` continues to be compiled as before. Where possible, classes will be compiled "bare", without an enclosing IIFE. This is possible when the class contains only ES2015 compatible expressions (methods and static methods), and has no parent (this last constraint is a result of the legacy `super` compilation, and could be removed once ES2015 `super` is being used). Classes are still assigned to variables to maintain compatibility for assigned class expressions. There are a few changes to existing functionality that could break backwards compatibility: - Derived constructors that deliberately don't call `super` are no longer possible. ES2015 derived classes can't use `this` unless the parent constructor has been called, so it's now called implicitly when not present. - As a consequence of the above, derived constructors with @ parameters or bound methods and explicit `super` calls are not allowed. The implicit `super` must be used in these cases. * Add tests to verify class interoperability with ES * Refactor class nodes to separate executable body logic Logic has been redistributed amongst the class nodes so that: - `Class` contains the logic necessary to compile an ES class declaration. - `ExecutableClassBody` contains the logic necessary to compile CS' class extensions that require an executable class body. `Class` still necessarily contains logic to determine whether an expression is valid in an ES class initializer or not. If any invalid expressions are found then `Class` will wrap itself in an `ExecutableClassBody` when compiling. * Rename `Code#static` to `Code#isStatic` This naming is more consistent with other `Code` flags. * Output anonymous classes when possible Anonymous classes can be output when: - The class has no parent. The current super compilation needs a class variable to reference. This condition will go away when ES2015 super is in use. - The class contains no bound static methods. Bound static methods have their context set to the class name. * Throw errors at compile time for async or generator constructors * Improve handling of anonymous classes Anonymous classes are now always anonymous. If a name is required (e.g. for bound static methods or derived classes) then the class is compiled in an `ExecutableClassBody` which will give the anonymous class a stable reference. * Add a `replaceInContext` method to `Node` `replaceInContext` will traverse children looking for a node for which `match` returns true. Once found, the matching node will be replaced by the result of calling `replacement`. * Separate `this` assignments from function parameters This change has been made to simplify two future changes: 1. Outputting `@`-param assignments after a `super` call. In this case it is necessary that non-`@` parameters are available before `super` is called, so destructuring has to happen before `this` assignment. 2. Compiling destructured assignment to ES6 In this case also destructuring has to happen before `this`, as destructuring can happen in the arguments list, but `this` assignment can not. A bonus side-effect is that default values for `@` params are now output as ES6 default parameters, e.g. (@a = 1) -> becomes function a (a = 1) { this.a = a; } * Change `super` handling in class constructors Inside an ES derived constructor (a constructor for a class that extends another class), it is impossible to access `this` until `super` has been called. This conflicts with CoffeeScript's `@`-param and bound method features, which compile to `this` references at the top of a function body. For example: class B extends A constructor: (@param) -> super method: => This would compile to something like: class B extends A { constructor (param) { this.param = param; this.method = bind(this.method, this); super(...arguments); } } This would break in an ES-compliant runtime as there are `this` references before the call to `super`. Before this commit we were dealing with this by injecting an implicit `super` call into derived constructors that do not already have an explicit `super` call. Furthermore, we would disallow explicit `super` calls in derived constructors that used bound methods or `@`-params, meaning the above example would need to be rewritten as: class B extends A constructor: (@param) -> method: => This would result in a call to `super(...arguments)` being generated as the first expression in `B#constructor`. Whilst this approach seems to work pretty well, and is arguably more convenient than having to manually call `super` when you don't particularly care about the arguments, it does introduce some 'magic' and separation from ES, and would likely be a pain point in a project that made use of significant constructor overriding. This commit introduces a mechanism through which `super` in constructors is 'expanded' to include any generated `this` assignments, whilst retaining the same semantics of a super call. The first example above now compiles to something like: class B extends A { constructor (param) { var ref ref = super(...arguments), this.param = param, this.method = bind(this.method, this), ref; } } * Improve `super` handling in constructors Rather than functions expanding their `super` calls, the `SuperCall` node can now be given a list of `thisAssignments` to apply when it is compiled. This allows us to use the normal compiler machinery to determine whether the `super` result needs to be cached, whether it appears inline or not, etc. * Fix anonymous classes at the top level Anonymous classes in ES are only valid within expressions. If an anonymous class is at the top level it will now be wrapped in parenthses to force it into an expression. * Re-add Parens wrapper around executable class bodies This was lost in the refactoring, but it necessary to ensure `new class ...` works as expected when there's an executable body. * Throw compiler errors for badly configured derived constructors Rather than letting them become runtime errors, the following checks are now performed when compiling a derived constructor: - The constructor **must** include a call to `super`. - The constructor **must not** reference `this` in the function body before `super` has been called. * Add some tests exercising new class behaviour - async methods in classes - `this` access after `super` in extended classes - constructor super in arrow functions - constructor functions can't be async - constructor functions can't be generators - derived constructors must call super - derived constructors can't reference `this` before calling super - generator methods in classes - 'new' target * Improve constructor `super` errors Add a check for `super` in non-extended class constructors, and explicitly mention derived constructors in the "can't reference this before super" error. * Fix compilation of multiple `super` paths in derived constructors `super` can only be called once, but it can be called conditionally from multiple locations. The chosen fix is to add the `this` assignments to every super call. * Additional class tests, added as a separate file to simplify testing and merging. Some methods are commented out because they currently throw and I'm not sure how to test for compilation errors like those. There is also one test which I deliberately left without passing, `super` in an external prototype override. This test should 'pass' but is really a variation on the failing `super only allowed in an instance method` tests above it. * Changes to the tests. Found bug in super in prototype method. fixed. * Added failing test back in, dealing with bound functions in external prototype overrides. * Located a bug in the compiler relating to assertions and escaped ES6 classes. * Move tests from classes-additional.coffee into classes.coffee; comment out console.log * Cleaned up tests and made changes based on feedback. Test at the end still has issues, but it's commented out for now. * Make HoistTarget.expand recursive It's possible that a hoisted node may itself contain hoisted nodes (e.g. a class method inside a class method). For this to work the hoisted fragments need to be expanded recursively. * Uncomment final test in classes.coffee The test case now compiles, however another issue is affecting the test due to the error for `this` before `super` triggering based on source order rather than execution order. These have been commented out for now. * Fixed last test TODOs in test/classes.coffee Turns out an expression like `this.foo = super()` won't run in JS as it attempts to lookup `this` before evaluating `super` (i.e. throws "this is not defined"). * Added more tests for compatability checks, statics, prototypes and ES6 expectations. Cleaned test "nested classes with super". * Changes to reflect feedback and to comment out issues that will be addressed seperately. * Clean up test/classes.coffee - Trim trailing whitespace. - Rephrase a condition to be more idiomatic. * Remove check for `super` in derived constructors In order to be usable at runtime, an extended ES class must call `super` OR return an alternative object. This check prevented the latter case, and checking for an alternative return can't be completed statically without control flow analysis. * Disallow 'super' in constructor parameter defaults There are many edge cases when combining 'super' in parameter defaults with @-parameters and bound functions (and potentially property initializers in the future). Rather than attempting to resolve these edge cases, 'super' is now explicitly disallowed in constructor parameter defaults. * Disallow @-params in derived constructors without 'super' @-parameters can't be assigned unless 'super' is called.
2017-01-13 00:55:30 -05:00
myArray = new MyArray
ok myArray instanceof MyArray
ok 'yes!', myArray.method()
[CS2] Compile class constructors to ES2015 classes (#4354) * Compile classes to ES2015 classes Rather than compiling classes to named functions with prototype and class assignments, they are now compiled to ES2015 class declarations. Backwards compatibility has been maintained by compiling ES2015- incompatible properties as prototype or class assignments. `super` continues to be compiled as before. Where possible, classes will be compiled "bare", without an enclosing IIFE. This is possible when the class contains only ES2015 compatible expressions (methods and static methods), and has no parent (this last constraint is a result of the legacy `super` compilation, and could be removed once ES2015 `super` is being used). Classes are still assigned to variables to maintain compatibility for assigned class expressions. There are a few changes to existing functionality that could break backwards compatibility: - Derived constructors that deliberately don't call `super` are no longer possible. ES2015 derived classes can't use `this` unless the parent constructor has been called, so it's now called implicitly when not present. - As a consequence of the above, derived constructors with @ parameters or bound methods and explicit `super` calls are not allowed. The implicit `super` must be used in these cases. * Add tests to verify class interoperability with ES * Refactor class nodes to separate executable body logic Logic has been redistributed amongst the class nodes so that: - `Class` contains the logic necessary to compile an ES class declaration. - `ExecutableClassBody` contains the logic necessary to compile CS' class extensions that require an executable class body. `Class` still necessarily contains logic to determine whether an expression is valid in an ES class initializer or not. If any invalid expressions are found then `Class` will wrap itself in an `ExecutableClassBody` when compiling. * Rename `Code#static` to `Code#isStatic` This naming is more consistent with other `Code` flags. * Output anonymous classes when possible Anonymous classes can be output when: - The class has no parent. The current super compilation needs a class variable to reference. This condition will go away when ES2015 super is in use. - The class contains no bound static methods. Bound static methods have their context set to the class name. * Throw errors at compile time for async or generator constructors * Improve handling of anonymous classes Anonymous classes are now always anonymous. If a name is required (e.g. for bound static methods or derived classes) then the class is compiled in an `ExecutableClassBody` which will give the anonymous class a stable reference. * Add a `replaceInContext` method to `Node` `replaceInContext` will traverse children looking for a node for which `match` returns true. Once found, the matching node will be replaced by the result of calling `replacement`. * Separate `this` assignments from function parameters This change has been made to simplify two future changes: 1. Outputting `@`-param assignments after a `super` call. In this case it is necessary that non-`@` parameters are available before `super` is called, so destructuring has to happen before `this` assignment. 2. Compiling destructured assignment to ES6 In this case also destructuring has to happen before `this`, as destructuring can happen in the arguments list, but `this` assignment can not. A bonus side-effect is that default values for `@` params are now output as ES6 default parameters, e.g. (@a = 1) -> becomes function a (a = 1) { this.a = a; } * Change `super` handling in class constructors Inside an ES derived constructor (a constructor for a class that extends another class), it is impossible to access `this` until `super` has been called. This conflicts with CoffeeScript's `@`-param and bound method features, which compile to `this` references at the top of a function body. For example: class B extends A constructor: (@param) -> super method: => This would compile to something like: class B extends A { constructor (param) { this.param = param; this.method = bind(this.method, this); super(...arguments); } } This would break in an ES-compliant runtime as there are `this` references before the call to `super`. Before this commit we were dealing with this by injecting an implicit `super` call into derived constructors that do not already have an explicit `super` call. Furthermore, we would disallow explicit `super` calls in derived constructors that used bound methods or `@`-params, meaning the above example would need to be rewritten as: class B extends A constructor: (@param) -> method: => This would result in a call to `super(...arguments)` being generated as the first expression in `B#constructor`. Whilst this approach seems to work pretty well, and is arguably more convenient than having to manually call `super` when you don't particularly care about the arguments, it does introduce some 'magic' and separation from ES, and would likely be a pain point in a project that made use of significant constructor overriding. This commit introduces a mechanism through which `super` in constructors is 'expanded' to include any generated `this` assignments, whilst retaining the same semantics of a super call. The first example above now compiles to something like: class B extends A { constructor (param) { var ref ref = super(...arguments), this.param = param, this.method = bind(this.method, this), ref; } } * Improve `super` handling in constructors Rather than functions expanding their `super` calls, the `SuperCall` node can now be given a list of `thisAssignments` to apply when it is compiled. This allows us to use the normal compiler machinery to determine whether the `super` result needs to be cached, whether it appears inline or not, etc. * Fix anonymous classes at the top level Anonymous classes in ES are only valid within expressions. If an anonymous class is at the top level it will now be wrapped in parenthses to force it into an expression. * Re-add Parens wrapper around executable class bodies This was lost in the refactoring, but it necessary to ensure `new class ...` works as expected when there's an executable body. * Throw compiler errors for badly configured derived constructors Rather than letting them become runtime errors, the following checks are now performed when compiling a derived constructor: - The constructor **must** include a call to `super`. - The constructor **must not** reference `this` in the function body before `super` has been called. * Add some tests exercising new class behaviour - async methods in classes - `this` access after `super` in extended classes - constructor super in arrow functions - constructor functions can't be async - constructor functions can't be generators - derived constructors must call super - derived constructors can't reference `this` before calling super - generator methods in classes - 'new' target * Improve constructor `super` errors Add a check for `super` in non-extended class constructors, and explicitly mention derived constructors in the "can't reference this before super" error. * Fix compilation of multiple `super` paths in derived constructors `super` can only be called once, but it can be called conditionally from multiple locations. The chosen fix is to add the `this` assignments to every super call. * Additional class tests, added as a separate file to simplify testing and merging. Some methods are commented out because they currently throw and I'm not sure how to test for compilation errors like those. There is also one test which I deliberately left without passing, `super` in an external prototype override. This test should 'pass' but is really a variation on the failing `super only allowed in an instance method` tests above it. * Changes to the tests. Found bug in super in prototype method. fixed. * Added failing test back in, dealing with bound functions in external prototype overrides. * Located a bug in the compiler relating to assertions and escaped ES6 classes. * Move tests from classes-additional.coffee into classes.coffee; comment out console.log * Cleaned up tests and made changes based on feedback. Test at the end still has issues, but it's commented out for now. * Make HoistTarget.expand recursive It's possible that a hoisted node may itself contain hoisted nodes (e.g. a class method inside a class method). For this to work the hoisted fragments need to be expanded recursively. * Uncomment final test in classes.coffee The test case now compiles, however another issue is affecting the test due to the error for `this` before `super` triggering based on source order rather than execution order. These have been commented out for now. * Fixed last test TODOs in test/classes.coffee Turns out an expression like `this.foo = super()` won't run in JS as it attempts to lookup `this` before evaluating `super` (i.e. throws "this is not defined"). * Added more tests for compatability checks, statics, prototypes and ES6 expectations. Cleaned test "nested classes with super". * Changes to reflect feedback and to comment out issues that will be addressed seperately. * Clean up test/classes.coffee - Trim trailing whitespace. - Rephrase a condition to be more idiomatic. * Remove check for `super` in derived constructors In order to be usable at runtime, an extended ES class must call `super` OR return an alternative object. This check prevented the latter case, and checking for an alternative return can't be completed statically without control flow analysis. * Disallow 'super' in constructor parameter defaults There are many edge cases when combining 'super' in parameter defaults with @-parameters and bound functions (and potentially property initializers in the future). Rather than attempting to resolve these edge cases, 'super' is now explicitly disallowed in constructor parameter defaults. * Disallow @-params in derived constructors without 'super' @-parameters can't be assigned unless 'super' is called.
2017-01-13 00:55:30 -05:00
class OverrideArray extends Array
[CS2] Compile all super calls to ES2015 super (#4424) * Compile all super calls to ES2015 super This breaks using `super` in non-methods, meaning several tests are failing. Self-compilation still works. * Use bound functions for IIFEs containing `super` `super` can only be called directly in a method, or in an arrow function. * Fix handling of `class @A extends A` This behaviour worked 'for free' when the parent reference was being cached by the executable class body wrapper. There now needs to be special handling in place to check if the parent name matches the class name, and if so to cache the parent reference. * Fix tests broken by compiling ES2015 `super` * Disallow bare super This removes syntax support for 'bare' super calls, e.g.: class B extends A constructor: -> super `super` must now always be followed with arguments like a regular function call. This also removes the capability of implicitly forwarding arguments. The above can be equivalently be written as: class B extends A constructor: -> super arguments... * Support super with accessors `super` with following accessor(s) is now compiled to ES2015 equivalents. In particular, expressions such as `super.name`, `super[name]`, and also `super.name.prop` are all now valid, and can be used as expected as calls (i.e. `super.name()`) or in expressions (i.e. `if super.name? ...`). `super` without accessors is compiled to a constructor super call in a constructor, and otherwise, as before, to a super call to the method of the same name, i.e. speak: -> super() ...is equivalent to speak: -> super.speak() A neat side-effect of the changes is that existential calls now work properly with super, meaning `super?()` will only call if the super property exists (and is a function). This is not valid for super in constructors. * Prevent calling `super` methods with `new` This fixes a bug in the previous super handling whereby using the `new` operator with a `super` call would silently drop the `new`. This is now an explicit compiler error, as it is invalid JS at runtime. * Clean up some old super handling code This was mostly code for tracking the source classes and variables for methods, which were needed to build the old lookups on `__super__`. * Add TODO to improve bare super parse error * Add some TODOs to improve some of the class tests
2017-02-04 15:03:17 -05:00
constructor: -> super()
method: -> 'yes!'
[CS2] Compile class constructors to ES2015 classes (#4354) * Compile classes to ES2015 classes Rather than compiling classes to named functions with prototype and class assignments, they are now compiled to ES2015 class declarations. Backwards compatibility has been maintained by compiling ES2015- incompatible properties as prototype or class assignments. `super` continues to be compiled as before. Where possible, classes will be compiled "bare", without an enclosing IIFE. This is possible when the class contains only ES2015 compatible expressions (methods and static methods), and has no parent (this last constraint is a result of the legacy `super` compilation, and could be removed once ES2015 `super` is being used). Classes are still assigned to variables to maintain compatibility for assigned class expressions. There are a few changes to existing functionality that could break backwards compatibility: - Derived constructors that deliberately don't call `super` are no longer possible. ES2015 derived classes can't use `this` unless the parent constructor has been called, so it's now called implicitly when not present. - As a consequence of the above, derived constructors with @ parameters or bound methods and explicit `super` calls are not allowed. The implicit `super` must be used in these cases. * Add tests to verify class interoperability with ES * Refactor class nodes to separate executable body logic Logic has been redistributed amongst the class nodes so that: - `Class` contains the logic necessary to compile an ES class declaration. - `ExecutableClassBody` contains the logic necessary to compile CS' class extensions that require an executable class body. `Class` still necessarily contains logic to determine whether an expression is valid in an ES class initializer or not. If any invalid expressions are found then `Class` will wrap itself in an `ExecutableClassBody` when compiling. * Rename `Code#static` to `Code#isStatic` This naming is more consistent with other `Code` flags. * Output anonymous classes when possible Anonymous classes can be output when: - The class has no parent. The current super compilation needs a class variable to reference. This condition will go away when ES2015 super is in use. - The class contains no bound static methods. Bound static methods have their context set to the class name. * Throw errors at compile time for async or generator constructors * Improve handling of anonymous classes Anonymous classes are now always anonymous. If a name is required (e.g. for bound static methods or derived classes) then the class is compiled in an `ExecutableClassBody` which will give the anonymous class a stable reference. * Add a `replaceInContext` method to `Node` `replaceInContext` will traverse children looking for a node for which `match` returns true. Once found, the matching node will be replaced by the result of calling `replacement`. * Separate `this` assignments from function parameters This change has been made to simplify two future changes: 1. Outputting `@`-param assignments after a `super` call. In this case it is necessary that non-`@` parameters are available before `super` is called, so destructuring has to happen before `this` assignment. 2. Compiling destructured assignment to ES6 In this case also destructuring has to happen before `this`, as destructuring can happen in the arguments list, but `this` assignment can not. A bonus side-effect is that default values for `@` params are now output as ES6 default parameters, e.g. (@a = 1) -> becomes function a (a = 1) { this.a = a; } * Change `super` handling in class constructors Inside an ES derived constructor (a constructor for a class that extends another class), it is impossible to access `this` until `super` has been called. This conflicts with CoffeeScript's `@`-param and bound method features, which compile to `this` references at the top of a function body. For example: class B extends A constructor: (@param) -> super method: => This would compile to something like: class B extends A { constructor (param) { this.param = param; this.method = bind(this.method, this); super(...arguments); } } This would break in an ES-compliant runtime as there are `this` references before the call to `super`. Before this commit we were dealing with this by injecting an implicit `super` call into derived constructors that do not already have an explicit `super` call. Furthermore, we would disallow explicit `super` calls in derived constructors that used bound methods or `@`-params, meaning the above example would need to be rewritten as: class B extends A constructor: (@param) -> method: => This would result in a call to `super(...arguments)` being generated as the first expression in `B#constructor`. Whilst this approach seems to work pretty well, and is arguably more convenient than having to manually call `super` when you don't particularly care about the arguments, it does introduce some 'magic' and separation from ES, and would likely be a pain point in a project that made use of significant constructor overriding. This commit introduces a mechanism through which `super` in constructors is 'expanded' to include any generated `this` assignments, whilst retaining the same semantics of a super call. The first example above now compiles to something like: class B extends A { constructor (param) { var ref ref = super(...arguments), this.param = param, this.method = bind(this.method, this), ref; } } * Improve `super` handling in constructors Rather than functions expanding their `super` calls, the `SuperCall` node can now be given a list of `thisAssignments` to apply when it is compiled. This allows us to use the normal compiler machinery to determine whether the `super` result needs to be cached, whether it appears inline or not, etc. * Fix anonymous classes at the top level Anonymous classes in ES are only valid within expressions. If an anonymous class is at the top level it will now be wrapped in parenthses to force it into an expression. * Re-add Parens wrapper around executable class bodies This was lost in the refactoring, but it necessary to ensure `new class ...` works as expected when there's an executable body. * Throw compiler errors for badly configured derived constructors Rather than letting them become runtime errors, the following checks are now performed when compiling a derived constructor: - The constructor **must** include a call to `super`. - The constructor **must not** reference `this` in the function body before `super` has been called. * Add some tests exercising new class behaviour - async methods in classes - `this` access after `super` in extended classes - constructor super in arrow functions - constructor functions can't be async - constructor functions can't be generators - derived constructors must call super - derived constructors can't reference `this` before calling super - generator methods in classes - 'new' target * Improve constructor `super` errors Add a check for `super` in non-extended class constructors, and explicitly mention derived constructors in the "can't reference this before super" error. * Fix compilation of multiple `super` paths in derived constructors `super` can only be called once, but it can be called conditionally from multiple locations. The chosen fix is to add the `this` assignments to every super call. * Additional class tests, added as a separate file to simplify testing and merging. Some methods are commented out because they currently throw and I'm not sure how to test for compilation errors like those. There is also one test which I deliberately left without passing, `super` in an external prototype override. This test should 'pass' but is really a variation on the failing `super only allowed in an instance method` tests above it. * Changes to the tests. Found bug in super in prototype method. fixed. * Added failing test back in, dealing with bound functions in external prototype overrides. * Located a bug in the compiler relating to assertions and escaped ES6 classes. * Move tests from classes-additional.coffee into classes.coffee; comment out console.log * Cleaned up tests and made changes based on feedback. Test at the end still has issues, but it's commented out for now. * Make HoistTarget.expand recursive It's possible that a hoisted node may itself contain hoisted nodes (e.g. a class method inside a class method). For this to work the hoisted fragments need to be expanded recursively. * Uncomment final test in classes.coffee The test case now compiles, however another issue is affecting the test due to the error for `this` before `super` triggering based on source order rather than execution order. These have been commented out for now. * Fixed last test TODOs in test/classes.coffee Turns out an expression like `this.foo = super()` won't run in JS as it attempts to lookup `this` before evaluating `super` (i.e. throws "this is not defined"). * Added more tests for compatability checks, statics, prototypes and ES6 expectations. Cleaned test "nested classes with super". * Changes to reflect feedback and to comment out issues that will be addressed seperately. * Clean up test/classes.coffee - Trim trailing whitespace. - Rephrase a condition to be more idiomatic. * Remove check for `super` in derived constructors In order to be usable at runtime, an extended ES class must call `super` OR return an alternative object. This check prevented the latter case, and checking for an alternative return can't be completed statically without control flow analysis. * Disallow 'super' in constructor parameter defaults There are many edge cases when combining 'super' in parameter defaults with @-parameters and bound functions (and potentially property initializers in the future). Rather than attempting to resolve these edge cases, 'super' is now explicitly disallowed in constructor parameter defaults. * Disallow @-params in derived constructors without 'super' @-parameters can't be assigned unless 'super' is called.
2017-01-13 00:55:30 -05:00
overrideArray = new OverrideArray
ok overrideArray instanceof OverrideArray
eq 'yes!', overrideArray.method()
test "#2782: non-alphanumeric-named bound functions", ->
class A
'b:c': =>
'd'
eq (new A)['b:c'](), 'd'
test "#2781: overriding bound functions", ->
class A
a: ->
@b()
b: =>
1
class B extends A
b: =>
2
b = (new A).b
eq b(), 1
b = (new B).b
eq b(), 2
test "#2791: bound function with destructured argument", ->
class Foo
method: ({a}) => 'Bar'
eq (new Foo).method({a: 'Bar'}), 'Bar'
test "#2796: ditto, ditto, ditto", ->
answer = null
outsideMethod = (func) ->
func.call message: 'wrong!'
class Base
constructor: ->
@message = 'right!'
outsideMethod @echo
echo: =>
answer = @message
new Base
eq answer, 'right!'
test "#3063: Class bodies cannot contain pure statements", ->
throwsCompileError """
class extends S
return if S.f
@f: => this
"""
test "#2949: super in static method with reserved name", ->
class Foo
@static: -> 'baz'
class Bar extends Foo
[CS2] Compile all super calls to ES2015 super (#4424) * Compile all super calls to ES2015 super This breaks using `super` in non-methods, meaning several tests are failing. Self-compilation still works. * Use bound functions for IIFEs containing `super` `super` can only be called directly in a method, or in an arrow function. * Fix handling of `class @A extends A` This behaviour worked 'for free' when the parent reference was being cached by the executable class body wrapper. There now needs to be special handling in place to check if the parent name matches the class name, and if so to cache the parent reference. * Fix tests broken by compiling ES2015 `super` * Disallow bare super This removes syntax support for 'bare' super calls, e.g.: class B extends A constructor: -> super `super` must now always be followed with arguments like a regular function call. This also removes the capability of implicitly forwarding arguments. The above can be equivalently be written as: class B extends A constructor: -> super arguments... * Support super with accessors `super` with following accessor(s) is now compiled to ES2015 equivalents. In particular, expressions such as `super.name`, `super[name]`, and also `super.name.prop` are all now valid, and can be used as expected as calls (i.e. `super.name()`) or in expressions (i.e. `if super.name? ...`). `super` without accessors is compiled to a constructor super call in a constructor, and otherwise, as before, to a super call to the method of the same name, i.e. speak: -> super() ...is equivalent to speak: -> super.speak() A neat side-effect of the changes is that existential calls now work properly with super, meaning `super?()` will only call if the super property exists (and is a function). This is not valid for super in constructors. * Prevent calling `super` methods with `new` This fixes a bug in the previous super handling whereby using the `new` operator with a `super` call would silently drop the `new`. This is now an explicit compiler error, as it is invalid JS at runtime. * Clean up some old super handling code This was mostly code for tracking the source classes and variables for methods, which were needed to build the old lookups on `__super__`. * Add TODO to improve bare super parse error * Add some TODOs to improve some of the class tests
2017-02-04 15:03:17 -05:00
@static: -> super()
eq Bar.static(), 'baz'
test "#3232: super in static methods (not object-assigned)", ->
class Foo
@baz = -> true
@qux = -> true
class Bar extends Foo
[CS2] Compile all super calls to ES2015 super (#4424) * Compile all super calls to ES2015 super This breaks using `super` in non-methods, meaning several tests are failing. Self-compilation still works. * Use bound functions for IIFEs containing `super` `super` can only be called directly in a method, or in an arrow function. * Fix handling of `class @A extends A` This behaviour worked 'for free' when the parent reference was being cached by the executable class body wrapper. There now needs to be special handling in place to check if the parent name matches the class name, and if so to cache the parent reference. * Fix tests broken by compiling ES2015 `super` * Disallow bare super This removes syntax support for 'bare' super calls, e.g.: class B extends A constructor: -> super `super` must now always be followed with arguments like a regular function call. This also removes the capability of implicitly forwarding arguments. The above can be equivalently be written as: class B extends A constructor: -> super arguments... * Support super with accessors `super` with following accessor(s) is now compiled to ES2015 equivalents. In particular, expressions such as `super.name`, `super[name]`, and also `super.name.prop` are all now valid, and can be used as expected as calls (i.e. `super.name()`) or in expressions (i.e. `if super.name? ...`). `super` without accessors is compiled to a constructor super call in a constructor, and otherwise, as before, to a super call to the method of the same name, i.e. speak: -> super() ...is equivalent to speak: -> super.speak() A neat side-effect of the changes is that existential calls now work properly with super, meaning `super?()` will only call if the super property exists (and is a function). This is not valid for super in constructors. * Prevent calling `super` methods with `new` This fixes a bug in the previous super handling whereby using the `new` operator with a `super` call would silently drop the `new`. This is now an explicit compiler error, as it is invalid JS at runtime. * Clean up some old super handling code This was mostly code for tracking the source classes and variables for methods, which were needed to build the old lookups on `__super__`. * Add TODO to improve bare super parse error * Add some TODOs to improve some of the class tests
2017-02-04 15:03:17 -05:00
@baz = -> super()
Bar.qux = -> super()
ok Bar.baz()
ok Bar.qux()
test "#1392 calling `super` in methods defined on namespaced classes", ->
class Base
m: -> 5
n: -> 4
namespace =
A: ->
B: ->
[CS2] Compile all super calls to ES2015 super (#4424) * Compile all super calls to ES2015 super This breaks using `super` in non-methods, meaning several tests are failing. Self-compilation still works. * Use bound functions for IIFEs containing `super` `super` can only be called directly in a method, or in an arrow function. * Fix handling of `class @A extends A` This behaviour worked 'for free' when the parent reference was being cached by the executable class body wrapper. There now needs to be special handling in place to check if the parent name matches the class name, and if so to cache the parent reference. * Fix tests broken by compiling ES2015 `super` * Disallow bare super This removes syntax support for 'bare' super calls, e.g.: class B extends A constructor: -> super `super` must now always be followed with arguments like a regular function call. This also removes the capability of implicitly forwarding arguments. The above can be equivalently be written as: class B extends A constructor: -> super arguments... * Support super with accessors `super` with following accessor(s) is now compiled to ES2015 equivalents. In particular, expressions such as `super.name`, `super[name]`, and also `super.name.prop` are all now valid, and can be used as expected as calls (i.e. `super.name()`) or in expressions (i.e. `if super.name? ...`). `super` without accessors is compiled to a constructor super call in a constructor, and otherwise, as before, to a super call to the method of the same name, i.e. speak: -> super() ...is equivalent to speak: -> super.speak() A neat side-effect of the changes is that existential calls now work properly with super, meaning `super?()` will only call if the super property exists (and is a function). This is not valid for super in constructors. * Prevent calling `super` methods with `new` This fixes a bug in the previous super handling whereby using the `new` operator with a `super` call would silently drop the `new`. This is now an explicit compiler error, as it is invalid JS at runtime. * Clean up some old super handling code This was mostly code for tracking the source classes and variables for methods, which were needed to build the old lookups on `__super__`. * Add TODO to improve bare super parse error * Add some TODOs to improve some of the class tests
2017-02-04 15:03:17 -05:00
class namespace.A extends Base
m: -> super()
eq 5, (new namespace.A).m()
namespace.B::m = namespace.A::m
namespace.A::m = null
eq 5, (new namespace.B).m()
class C
[CS2] Compile all super calls to ES2015 super (#4424) * Compile all super calls to ES2015 super This breaks using `super` in non-methods, meaning several tests are failing. Self-compilation still works. * Use bound functions for IIFEs containing `super` `super` can only be called directly in a method, or in an arrow function. * Fix handling of `class @A extends A` This behaviour worked 'for free' when the parent reference was being cached by the executable class body wrapper. There now needs to be special handling in place to check if the parent name matches the class name, and if so to cache the parent reference. * Fix tests broken by compiling ES2015 `super` * Disallow bare super This removes syntax support for 'bare' super calls, e.g.: class B extends A constructor: -> super `super` must now always be followed with arguments like a regular function call. This also removes the capability of implicitly forwarding arguments. The above can be equivalently be written as: class B extends A constructor: -> super arguments... * Support super with accessors `super` with following accessor(s) is now compiled to ES2015 equivalents. In particular, expressions such as `super.name`, `super[name]`, and also `super.name.prop` are all now valid, and can be used as expected as calls (i.e. `super.name()`) or in expressions (i.e. `if super.name? ...`). `super` without accessors is compiled to a constructor super call in a constructor, and otherwise, as before, to a super call to the method of the same name, i.e. speak: -> super() ...is equivalent to speak: -> super.speak() A neat side-effect of the changes is that existential calls now work properly with super, meaning `super?()` will only call if the super property exists (and is a function). This is not valid for super in constructors. * Prevent calling `super` methods with `new` This fixes a bug in the previous super handling whereby using the `new` operator with a `super` call would silently drop the `new`. This is now an explicit compiler error, as it is invalid JS at runtime. * Clean up some old super handling code This was mostly code for tracking the source classes and variables for methods, which were needed to build the old lookups on `__super__`. * Add TODO to improve bare super parse error * Add some TODOs to improve some of the class tests
2017-02-04 15:03:17 -05:00
@a: class extends Base
m: -> super()
eq 5, (new C.a).m()
test "#4436 immediately instantiated named class", ->
ok new class Foo
test "dynamic method names", ->
class A
"#{name = 'm'}": -> 1
eq 1, new A().m()
class B extends A
[CS2] Compile all super calls to ES2015 super (#4424) * Compile all super calls to ES2015 super This breaks using `super` in non-methods, meaning several tests are failing. Self-compilation still works. * Use bound functions for IIFEs containing `super` `super` can only be called directly in a method, or in an arrow function. * Fix handling of `class @A extends A` This behaviour worked 'for free' when the parent reference was being cached by the executable class body wrapper. There now needs to be special handling in place to check if the parent name matches the class name, and if so to cache the parent reference. * Fix tests broken by compiling ES2015 `super` * Disallow bare super This removes syntax support for 'bare' super calls, e.g.: class B extends A constructor: -> super `super` must now always be followed with arguments like a regular function call. This also removes the capability of implicitly forwarding arguments. The above can be equivalently be written as: class B extends A constructor: -> super arguments... * Support super with accessors `super` with following accessor(s) is now compiled to ES2015 equivalents. In particular, expressions such as `super.name`, `super[name]`, and also `super.name.prop` are all now valid, and can be used as expected as calls (i.e. `super.name()`) or in expressions (i.e. `if super.name? ...`). `super` without accessors is compiled to a constructor super call in a constructor, and otherwise, as before, to a super call to the method of the same name, i.e. speak: -> super() ...is equivalent to speak: -> super.speak() A neat side-effect of the changes is that existential calls now work properly with super, meaning `super?()` will only call if the super property exists (and is a function). This is not valid for super in constructors. * Prevent calling `super` methods with `new` This fixes a bug in the previous super handling whereby using the `new` operator with a `super` call would silently drop the `new`. This is now an explicit compiler error, as it is invalid JS at runtime. * Clean up some old super handling code This was mostly code for tracking the source classes and variables for methods, which were needed to build the old lookups on `__super__`. * Add TODO to improve bare super parse error * Add some TODOs to improve some of the class tests
2017-02-04 15:03:17 -05:00
"#{name = 'm'}": -> super()
eq 1, new B().m()
getName = -> 'm'
class C
"#{name = getName()}": -> 1
eq 1, new C().m()
test "dynamic method names and super", ->
class Base
@m: -> 6
m: -> 5
2015-02-07 14:16:59 -05:00
m2: -> 4.5
n: -> 4
[CS2] Compile all super calls to ES2015 super (#4424) * Compile all super calls to ES2015 super This breaks using `super` in non-methods, meaning several tests are failing. Self-compilation still works. * Use bound functions for IIFEs containing `super` `super` can only be called directly in a method, or in an arrow function. * Fix handling of `class @A extends A` This behaviour worked 'for free' when the parent reference was being cached by the executable class body wrapper. There now needs to be special handling in place to check if the parent name matches the class name, and if so to cache the parent reference. * Fix tests broken by compiling ES2015 `super` * Disallow bare super This removes syntax support for 'bare' super calls, e.g.: class B extends A constructor: -> super `super` must now always be followed with arguments like a regular function call. This also removes the capability of implicitly forwarding arguments. The above can be equivalently be written as: class B extends A constructor: -> super arguments... * Support super with accessors `super` with following accessor(s) is now compiled to ES2015 equivalents. In particular, expressions such as `super.name`, `super[name]`, and also `super.name.prop` are all now valid, and can be used as expected as calls (i.e. `super.name()`) or in expressions (i.e. `if super.name? ...`). `super` without accessors is compiled to a constructor super call in a constructor, and otherwise, as before, to a super call to the method of the same name, i.e. speak: -> super() ...is equivalent to speak: -> super.speak() A neat side-effect of the changes is that existential calls now work properly with super, meaning `super?()` will only call if the super property exists (and is a function). This is not valid for super in constructors. * Prevent calling `super` methods with `new` This fixes a bug in the previous super handling whereby using the `new` operator with a `super` call would silently drop the `new`. This is now an explicit compiler error, as it is invalid JS at runtime. * Clean up some old super handling code This was mostly code for tracking the source classes and variables for methods, which were needed to build the old lookups on `__super__`. * Add TODO to improve bare super parse error * Add some TODOs to improve some of the class tests
2017-02-04 15:03:17 -05:00
name = -> count++; 'n'
count = 0
m = 'm'
[CS2] Compile all super calls to ES2015 super (#4424) * Compile all super calls to ES2015 super This breaks using `super` in non-methods, meaning several tests are failing. Self-compilation still works. * Use bound functions for IIFEs containing `super` `super` can only be called directly in a method, or in an arrow function. * Fix handling of `class @A extends A` This behaviour worked 'for free' when the parent reference was being cached by the executable class body wrapper. There now needs to be special handling in place to check if the parent name matches the class name, and if so to cache the parent reference. * Fix tests broken by compiling ES2015 `super` * Disallow bare super This removes syntax support for 'bare' super calls, e.g.: class B extends A constructor: -> super `super` must now always be followed with arguments like a regular function call. This also removes the capability of implicitly forwarding arguments. The above can be equivalently be written as: class B extends A constructor: -> super arguments... * Support super with accessors `super` with following accessor(s) is now compiled to ES2015 equivalents. In particular, expressions such as `super.name`, `super[name]`, and also `super.name.prop` are all now valid, and can be used as expected as calls (i.e. `super.name()`) or in expressions (i.e. `if super.name? ...`). `super` without accessors is compiled to a constructor super call in a constructor, and otherwise, as before, to a super call to the method of the same name, i.e. speak: -> super() ...is equivalent to speak: -> super.speak() A neat side-effect of the changes is that existential calls now work properly with super, meaning `super?()` will only call if the super property exists (and is a function). This is not valid for super in constructors. * Prevent calling `super` methods with `new` This fixes a bug in the previous super handling whereby using the `new` operator with a `super` call would silently drop the `new`. This is now an explicit compiler error, as it is invalid JS at runtime. * Clean up some old super handling code This was mostly code for tracking the source classes and variables for methods, which were needed to build the old lookups on `__super__`. * Add TODO to improve bare super parse error * Add some TODOs to improve some of the class tests
2017-02-04 15:03:17 -05:00
class A extends Base
"#{m}": -> super()
"#{name()}": -> super()
m = 'n'
eq 5, (new A).m()
eq 4, (new A).n()
eq 1, count
m = 'm'
2015-02-07 14:16:59 -05:00
m2 = 'm2'
count = 0
class B extends Base
[CS2] Compile all super calls to ES2015 super (#4424) * Compile all super calls to ES2015 super This breaks using `super` in non-methods, meaning several tests are failing. Self-compilation still works. * Use bound functions for IIFEs containing `super` `super` can only be called directly in a method, or in an arrow function. * Fix handling of `class @A extends A` This behaviour worked 'for free' when the parent reference was being cached by the executable class body wrapper. There now needs to be special handling in place to check if the parent name matches the class name, and if so to cache the parent reference. * Fix tests broken by compiling ES2015 `super` * Disallow bare super This removes syntax support for 'bare' super calls, e.g.: class B extends A constructor: -> super `super` must now always be followed with arguments like a regular function call. This also removes the capability of implicitly forwarding arguments. The above can be equivalently be written as: class B extends A constructor: -> super arguments... * Support super with accessors `super` with following accessor(s) is now compiled to ES2015 equivalents. In particular, expressions such as `super.name`, `super[name]`, and also `super.name.prop` are all now valid, and can be used as expected as calls (i.e. `super.name()`) or in expressions (i.e. `if super.name? ...`). `super` without accessors is compiled to a constructor super call in a constructor, and otherwise, as before, to a super call to the method of the same name, i.e. speak: -> super() ...is equivalent to speak: -> super.speak() A neat side-effect of the changes is that existential calls now work properly with super, meaning `super?()` will only call if the super property exists (and is a function). This is not valid for super in constructors. * Prevent calling `super` methods with `new` This fixes a bug in the previous super handling whereby using the `new` operator with a `super` call would silently drop the `new`. This is now an explicit compiler error, as it is invalid JS at runtime. * Clean up some old super handling code This was mostly code for tracking the source classes and variables for methods, which were needed to build the old lookups on `__super__`. * Add TODO to improve bare super parse error * Add some TODOs to improve some of the class tests
2017-02-04 15:03:17 -05:00
@[name()] = -> super()
"#{m}": -> super()
"#{m2}": -> super()
b = new B
2015-02-07 14:16:59 -05:00
m = m2 = 'n'
eq 6, B.m()
eq 5, b.m()
2015-02-07 14:16:59 -05:00
eq 4.5, b.m2()
eq 1, count
class C extends B
[CS2] Compile all super calls to ES2015 super (#4424) * Compile all super calls to ES2015 super This breaks using `super` in non-methods, meaning several tests are failing. Self-compilation still works. * Use bound functions for IIFEs containing `super` `super` can only be called directly in a method, or in an arrow function. * Fix handling of `class @A extends A` This behaviour worked 'for free' when the parent reference was being cached by the executable class body wrapper. There now needs to be special handling in place to check if the parent name matches the class name, and if so to cache the parent reference. * Fix tests broken by compiling ES2015 `super` * Disallow bare super This removes syntax support for 'bare' super calls, e.g.: class B extends A constructor: -> super `super` must now always be followed with arguments like a regular function call. This also removes the capability of implicitly forwarding arguments. The above can be equivalently be written as: class B extends A constructor: -> super arguments... * Support super with accessors `super` with following accessor(s) is now compiled to ES2015 equivalents. In particular, expressions such as `super.name`, `super[name]`, and also `super.name.prop` are all now valid, and can be used as expected as calls (i.e. `super.name()`) or in expressions (i.e. `if super.name? ...`). `super` without accessors is compiled to a constructor super call in a constructor, and otherwise, as before, to a super call to the method of the same name, i.e. speak: -> super() ...is equivalent to speak: -> super.speak() A neat side-effect of the changes is that existential calls now work properly with super, meaning `super?()` will only call if the super property exists (and is a function). This is not valid for super in constructors. * Prevent calling `super` methods with `new` This fixes a bug in the previous super handling whereby using the `new` operator with a `super` call would silently drop the `new`. This is now an explicit compiler error, as it is invalid JS at runtime. * Clean up some old super handling code This was mostly code for tracking the source classes and variables for methods, which were needed to build the old lookups on `__super__`. * Add TODO to improve bare super parse error * Add some TODOs to improve some of the class tests
2017-02-04 15:03:17 -05:00
m: -> super()
eq 5, (new C).m()
[CS2] Compile class constructors to ES2015 classes (#4354) * Compile classes to ES2015 classes Rather than compiling classes to named functions with prototype and class assignments, they are now compiled to ES2015 class declarations. Backwards compatibility has been maintained by compiling ES2015- incompatible properties as prototype or class assignments. `super` continues to be compiled as before. Where possible, classes will be compiled "bare", without an enclosing IIFE. This is possible when the class contains only ES2015 compatible expressions (methods and static methods), and has no parent (this last constraint is a result of the legacy `super` compilation, and could be removed once ES2015 `super` is being used). Classes are still assigned to variables to maintain compatibility for assigned class expressions. There are a few changes to existing functionality that could break backwards compatibility: - Derived constructors that deliberately don't call `super` are no longer possible. ES2015 derived classes can't use `this` unless the parent constructor has been called, so it's now called implicitly when not present. - As a consequence of the above, derived constructors with @ parameters or bound methods and explicit `super` calls are not allowed. The implicit `super` must be used in these cases. * Add tests to verify class interoperability with ES * Refactor class nodes to separate executable body logic Logic has been redistributed amongst the class nodes so that: - `Class` contains the logic necessary to compile an ES class declaration. - `ExecutableClassBody` contains the logic necessary to compile CS' class extensions that require an executable class body. `Class` still necessarily contains logic to determine whether an expression is valid in an ES class initializer or not. If any invalid expressions are found then `Class` will wrap itself in an `ExecutableClassBody` when compiling. * Rename `Code#static` to `Code#isStatic` This naming is more consistent with other `Code` flags. * Output anonymous classes when possible Anonymous classes can be output when: - The class has no parent. The current super compilation needs a class variable to reference. This condition will go away when ES2015 super is in use. - The class contains no bound static methods. Bound static methods have their context set to the class name. * Throw errors at compile time for async or generator constructors * Improve handling of anonymous classes Anonymous classes are now always anonymous. If a name is required (e.g. for bound static methods or derived classes) then the class is compiled in an `ExecutableClassBody` which will give the anonymous class a stable reference. * Add a `replaceInContext` method to `Node` `replaceInContext` will traverse children looking for a node for which `match` returns true. Once found, the matching node will be replaced by the result of calling `replacement`. * Separate `this` assignments from function parameters This change has been made to simplify two future changes: 1. Outputting `@`-param assignments after a `super` call. In this case it is necessary that non-`@` parameters are available before `super` is called, so destructuring has to happen before `this` assignment. 2. Compiling destructured assignment to ES6 In this case also destructuring has to happen before `this`, as destructuring can happen in the arguments list, but `this` assignment can not. A bonus side-effect is that default values for `@` params are now output as ES6 default parameters, e.g. (@a = 1) -> becomes function a (a = 1) { this.a = a; } * Change `super` handling in class constructors Inside an ES derived constructor (a constructor for a class that extends another class), it is impossible to access `this` until `super` has been called. This conflicts with CoffeeScript's `@`-param and bound method features, which compile to `this` references at the top of a function body. For example: class B extends A constructor: (@param) -> super method: => This would compile to something like: class B extends A { constructor (param) { this.param = param; this.method = bind(this.method, this); super(...arguments); } } This would break in an ES-compliant runtime as there are `this` references before the call to `super`. Before this commit we were dealing with this by injecting an implicit `super` call into derived constructors that do not already have an explicit `super` call. Furthermore, we would disallow explicit `super` calls in derived constructors that used bound methods or `@`-params, meaning the above example would need to be rewritten as: class B extends A constructor: (@param) -> method: => This would result in a call to `super(...arguments)` being generated as the first expression in `B#constructor`. Whilst this approach seems to work pretty well, and is arguably more convenient than having to manually call `super` when you don't particularly care about the arguments, it does introduce some 'magic' and separation from ES, and would likely be a pain point in a project that made use of significant constructor overriding. This commit introduces a mechanism through which `super` in constructors is 'expanded' to include any generated `this` assignments, whilst retaining the same semantics of a super call. The first example above now compiles to something like: class B extends A { constructor (param) { var ref ref = super(...arguments), this.param = param, this.method = bind(this.method, this), ref; } } * Improve `super` handling in constructors Rather than functions expanding their `super` calls, the `SuperCall` node can now be given a list of `thisAssignments` to apply when it is compiled. This allows us to use the normal compiler machinery to determine whether the `super` result needs to be cached, whether it appears inline or not, etc. * Fix anonymous classes at the top level Anonymous classes in ES are only valid within expressions. If an anonymous class is at the top level it will now be wrapped in parenthses to force it into an expression. * Re-add Parens wrapper around executable class bodies This was lost in the refactoring, but it necessary to ensure `new class ...` works as expected when there's an executable body. * Throw compiler errors for badly configured derived constructors Rather than letting them become runtime errors, the following checks are now performed when compiling a derived constructor: - The constructor **must** include a call to `super`. - The constructor **must not** reference `this` in the function body before `super` has been called. * Add some tests exercising new class behaviour - async methods in classes - `this` access after `super` in extended classes - constructor super in arrow functions - constructor functions can't be async - constructor functions can't be generators - derived constructors must call super - derived constructors can't reference `this` before calling super - generator methods in classes - 'new' target * Improve constructor `super` errors Add a check for `super` in non-extended class constructors, and explicitly mention derived constructors in the "can't reference this before super" error. * Fix compilation of multiple `super` paths in derived constructors `super` can only be called once, but it can be called conditionally from multiple locations. The chosen fix is to add the `this` assignments to every super call. * Additional class tests, added as a separate file to simplify testing and merging. Some methods are commented out because they currently throw and I'm not sure how to test for compilation errors like those. There is also one test which I deliberately left without passing, `super` in an external prototype override. This test should 'pass' but is really a variation on the failing `super only allowed in an instance method` tests above it. * Changes to the tests. Found bug in super in prototype method. fixed. * Added failing test back in, dealing with bound functions in external prototype overrides. * Located a bug in the compiler relating to assertions and escaped ES6 classes. * Move tests from classes-additional.coffee into classes.coffee; comment out console.log * Cleaned up tests and made changes based on feedback. Test at the end still has issues, but it's commented out for now. * Make HoistTarget.expand recursive It's possible that a hoisted node may itself contain hoisted nodes (e.g. a class method inside a class method). For this to work the hoisted fragments need to be expanded recursively. * Uncomment final test in classes.coffee The test case now compiles, however another issue is affecting the test due to the error for `this` before `super` triggering based on source order rather than execution order. These have been commented out for now. * Fixed last test TODOs in test/classes.coffee Turns out an expression like `this.foo = super()` won't run in JS as it attempts to lookup `this` before evaluating `super` (i.e. throws "this is not defined"). * Added more tests for compatability checks, statics, prototypes and ES6 expectations. Cleaned test "nested classes with super". * Changes to reflect feedback and to comment out issues that will be addressed seperately. * Clean up test/classes.coffee - Trim trailing whitespace. - Rephrase a condition to be more idiomatic. * Remove check for `super` in derived constructors In order to be usable at runtime, an extended ES class must call `super` OR return an alternative object. This check prevented the latter case, and checking for an alternative return can't be completed statically without control flow analysis. * Disallow 'super' in constructor parameter defaults There are many edge cases when combining 'super' in parameter defaults with @-parameters and bound functions (and potentially property initializers in the future). Rather than attempting to resolve these edge cases, 'super' is now explicitly disallowed in constructor parameter defaults. * Disallow @-params in derived constructors without 'super' @-parameters can't be assigned unless 'super' is called.
2017-01-13 00:55:30 -05:00
# ES2015+ class interoperability
# Based on https://github.com/balupton/es6-javascript-class-interop
# Helper functions to generate true ES classes to extend:
getBasicClass = ->
```
class BasicClass {
constructor (greeting) {
this.greeting = greeting || 'hi'
}
}
```
BasicClass
getExtendedClass = (BaseClass) ->
```
class ExtendedClass extends BaseClass {
constructor (greeting, name) {
super(greeting || 'hello')
this.name = name
}
}
```
ExtendedClass
test "can instantiate a basic ES class", ->
BasicClass = getBasicClass()
i = new BasicClass 'howdy!'
eq i.greeting, 'howdy!'
test "can instantiate an extended ES class", ->
BasicClass = getBasicClass()
ExtendedClass = getExtendedClass BasicClass
i = new ExtendedClass 'yo', 'buddy'
eq i.greeting, 'yo'
eq i.name, 'buddy'
test "can extend a basic ES class", ->
BasicClass = getBasicClass()
class ExtendedClass extends BasicClass
constructor: (@name) ->
super()
i = new ExtendedClass 'dude'
eq i.name, 'dude'
test "can extend an extended ES class", ->
BasicClass = getBasicClass()
ExtendedClass = getExtendedClass BasicClass
class ExtendedExtendedClass extends ExtendedClass
constructor: (@value) ->
super()
getDoubledValue: ->
@value * 2
i = new ExtendedExtendedClass 7
eq i.getDoubledValue(), 14
test "CoffeeScript class can be extended in ES", ->
class CoffeeClass
constructor: (@favoriteDrink = 'latte', @size = 'grande') ->
getDrinkOrder: ->
"#{@size} #{@favoriteDrink}"
```
class ECMAScriptClass extends CoffeeClass {
constructor (favoriteDrink) {
super(favoriteDrink);
this.favoriteDrink = this.favoriteDrink + ' with a dash of semicolons';
}
}
```
e = new ECMAScriptClass 'coffee'
eq e.getDrinkOrder(), 'grande coffee with a dash of semicolons'
test "extended CoffeeScript class can be extended in ES", ->
class CoffeeClass
constructor: (@favoriteDrink = 'latte') ->
class CoffeeClassWithDrinkOrder extends CoffeeClass
constructor: (@favoriteDrink, @size = 'grande') ->
super()
getDrinkOrder: ->
"#{@size} #{@favoriteDrink}"
```
class ECMAScriptClass extends CoffeeClassWithDrinkOrder {
constructor (favoriteDrink) {
super(favoriteDrink);
this.favoriteDrink = this.favoriteDrink + ' with a dash of semicolons';
}
}
```
e = new ECMAScriptClass 'coffee'
eq e.getDrinkOrder(), 'grande coffee with a dash of semicolons'
test "`this` access after `super` in extended classes", ->
class Base
class Test extends Base
constructor: (param, @param) ->
eq param, nonce
result = { super: super(), @param, @method }
eq result.super, this
eq result.param, @param
eq result.method, @method
ok result.method isnt Test::method
method: =>
[CS2] Compile class constructors to ES2015 classes (#4354) * Compile classes to ES2015 classes Rather than compiling classes to named functions with prototype and class assignments, they are now compiled to ES2015 class declarations. Backwards compatibility has been maintained by compiling ES2015- incompatible properties as prototype or class assignments. `super` continues to be compiled as before. Where possible, classes will be compiled "bare", without an enclosing IIFE. This is possible when the class contains only ES2015 compatible expressions (methods and static methods), and has no parent (this last constraint is a result of the legacy `super` compilation, and could be removed once ES2015 `super` is being used). Classes are still assigned to variables to maintain compatibility for assigned class expressions. There are a few changes to existing functionality that could break backwards compatibility: - Derived constructors that deliberately don't call `super` are no longer possible. ES2015 derived classes can't use `this` unless the parent constructor has been called, so it's now called implicitly when not present. - As a consequence of the above, derived constructors with @ parameters or bound methods and explicit `super` calls are not allowed. The implicit `super` must be used in these cases. * Add tests to verify class interoperability with ES * Refactor class nodes to separate executable body logic Logic has been redistributed amongst the class nodes so that: - `Class` contains the logic necessary to compile an ES class declaration. - `ExecutableClassBody` contains the logic necessary to compile CS' class extensions that require an executable class body. `Class` still necessarily contains logic to determine whether an expression is valid in an ES class initializer or not. If any invalid expressions are found then `Class` will wrap itself in an `ExecutableClassBody` when compiling. * Rename `Code#static` to `Code#isStatic` This naming is more consistent with other `Code` flags. * Output anonymous classes when possible Anonymous classes can be output when: - The class has no parent. The current super compilation needs a class variable to reference. This condition will go away when ES2015 super is in use. - The class contains no bound static methods. Bound static methods have their context set to the class name. * Throw errors at compile time for async or generator constructors * Improve handling of anonymous classes Anonymous classes are now always anonymous. If a name is required (e.g. for bound static methods or derived classes) then the class is compiled in an `ExecutableClassBody` which will give the anonymous class a stable reference. * Add a `replaceInContext` method to `Node` `replaceInContext` will traverse children looking for a node for which `match` returns true. Once found, the matching node will be replaced by the result of calling `replacement`. * Separate `this` assignments from function parameters This change has been made to simplify two future changes: 1. Outputting `@`-param assignments after a `super` call. In this case it is necessary that non-`@` parameters are available before `super` is called, so destructuring has to happen before `this` assignment. 2. Compiling destructured assignment to ES6 In this case also destructuring has to happen before `this`, as destructuring can happen in the arguments list, but `this` assignment can not. A bonus side-effect is that default values for `@` params are now output as ES6 default parameters, e.g. (@a = 1) -> becomes function a (a = 1) { this.a = a; } * Change `super` handling in class constructors Inside an ES derived constructor (a constructor for a class that extends another class), it is impossible to access `this` until `super` has been called. This conflicts with CoffeeScript's `@`-param and bound method features, which compile to `this` references at the top of a function body. For example: class B extends A constructor: (@param) -> super method: => This would compile to something like: class B extends A { constructor (param) { this.param = param; this.method = bind(this.method, this); super(...arguments); } } This would break in an ES-compliant runtime as there are `this` references before the call to `super`. Before this commit we were dealing with this by injecting an implicit `super` call into derived constructors that do not already have an explicit `super` call. Furthermore, we would disallow explicit `super` calls in derived constructors that used bound methods or `@`-params, meaning the above example would need to be rewritten as: class B extends A constructor: (@param) -> method: => This would result in a call to `super(...arguments)` being generated as the first expression in `B#constructor`. Whilst this approach seems to work pretty well, and is arguably more convenient than having to manually call `super` when you don't particularly care about the arguments, it does introduce some 'magic' and separation from ES, and would likely be a pain point in a project that made use of significant constructor overriding. This commit introduces a mechanism through which `super` in constructors is 'expanded' to include any generated `this` assignments, whilst retaining the same semantics of a super call. The first example above now compiles to something like: class B extends A { constructor (param) { var ref ref = super(...arguments), this.param = param, this.method = bind(this.method, this), ref; } } * Improve `super` handling in constructors Rather than functions expanding their `super` calls, the `SuperCall` node can now be given a list of `thisAssignments` to apply when it is compiled. This allows us to use the normal compiler machinery to determine whether the `super` result needs to be cached, whether it appears inline or not, etc. * Fix anonymous classes at the top level Anonymous classes in ES are only valid within expressions. If an anonymous class is at the top level it will now be wrapped in parenthses to force it into an expression. * Re-add Parens wrapper around executable class bodies This was lost in the refactoring, but it necessary to ensure `new class ...` works as expected when there's an executable body. * Throw compiler errors for badly configured derived constructors Rather than letting them become runtime errors, the following checks are now performed when compiling a derived constructor: - The constructor **must** include a call to `super`. - The constructor **must not** reference `this` in the function body before `super` has been called. * Add some tests exercising new class behaviour - async methods in classes - `this` access after `super` in extended classes - constructor super in arrow functions - constructor functions can't be async - constructor functions can't be generators - derived constructors must call super - derived constructors can't reference `this` before calling super - generator methods in classes - 'new' target * Improve constructor `super` errors Add a check for `super` in non-extended class constructors, and explicitly mention derived constructors in the "can't reference this before super" error. * Fix compilation of multiple `super` paths in derived constructors `super` can only be called once, but it can be called conditionally from multiple locations. The chosen fix is to add the `this` assignments to every super call. * Additional class tests, added as a separate file to simplify testing and merging. Some methods are commented out because they currently throw and I'm not sure how to test for compilation errors like those. There is also one test which I deliberately left without passing, `super` in an external prototype override. This test should 'pass' but is really a variation on the failing `super only allowed in an instance method` tests above it. * Changes to the tests. Found bug in super in prototype method. fixed. * Added failing test back in, dealing with bound functions in external prototype overrides. * Located a bug in the compiler relating to assertions and escaped ES6 classes. * Move tests from classes-additional.coffee into classes.coffee; comment out console.log * Cleaned up tests and made changes based on feedback. Test at the end still has issues, but it's commented out for now. * Make HoistTarget.expand recursive It's possible that a hoisted node may itself contain hoisted nodes (e.g. a class method inside a class method). For this to work the hoisted fragments need to be expanded recursively. * Uncomment final test in classes.coffee The test case now compiles, however another issue is affecting the test due to the error for `this` before `super` triggering based on source order rather than execution order. These have been commented out for now. * Fixed last test TODOs in test/classes.coffee Turns out an expression like `this.foo = super()` won't run in JS as it attempts to lookup `this` before evaluating `super` (i.e. throws "this is not defined"). * Added more tests for compatability checks, statics, prototypes and ES6 expectations. Cleaned test "nested classes with super". * Changes to reflect feedback and to comment out issues that will be addressed seperately. * Clean up test/classes.coffee - Trim trailing whitespace. - Rephrase a condition to be more idiomatic. * Remove check for `super` in derived constructors In order to be usable at runtime, an extended ES class must call `super` OR return an alternative object. This check prevented the latter case, and checking for an alternative return can't be completed statically without control flow analysis. * Disallow 'super' in constructor parameter defaults There are many edge cases when combining 'super' in parameter defaults with @-parameters and bound functions (and potentially property initializers in the future). Rather than attempting to resolve these edge cases, 'super' is now explicitly disallowed in constructor parameter defaults. * Disallow @-params in derived constructors without 'super' @-parameters can't be assigned unless 'super' is called.
2017-01-13 00:55:30 -05:00
nonce = {}
new Test nonce, {}
test "`@`-params and bound methods with multiple `super` paths (blocks)", ->
nonce = {}
class Base
constructor: (@name) ->
class Test extends Base
constructor: (param, @param) ->
if param
super 'param'
eq @name, 'param'
else
super 'not param'
eq @name, 'not param'
eq @param, nonce
ok @method isnt Test::method
method: =>
[CS2] Compile class constructors to ES2015 classes (#4354) * Compile classes to ES2015 classes Rather than compiling classes to named functions with prototype and class assignments, they are now compiled to ES2015 class declarations. Backwards compatibility has been maintained by compiling ES2015- incompatible properties as prototype or class assignments. `super` continues to be compiled as before. Where possible, classes will be compiled "bare", without an enclosing IIFE. This is possible when the class contains only ES2015 compatible expressions (methods and static methods), and has no parent (this last constraint is a result of the legacy `super` compilation, and could be removed once ES2015 `super` is being used). Classes are still assigned to variables to maintain compatibility for assigned class expressions. There are a few changes to existing functionality that could break backwards compatibility: - Derived constructors that deliberately don't call `super` are no longer possible. ES2015 derived classes can't use `this` unless the parent constructor has been called, so it's now called implicitly when not present. - As a consequence of the above, derived constructors with @ parameters or bound methods and explicit `super` calls are not allowed. The implicit `super` must be used in these cases. * Add tests to verify class interoperability with ES * Refactor class nodes to separate executable body logic Logic has been redistributed amongst the class nodes so that: - `Class` contains the logic necessary to compile an ES class declaration. - `ExecutableClassBody` contains the logic necessary to compile CS' class extensions that require an executable class body. `Class` still necessarily contains logic to determine whether an expression is valid in an ES class initializer or not. If any invalid expressions are found then `Class` will wrap itself in an `ExecutableClassBody` when compiling. * Rename `Code#static` to `Code#isStatic` This naming is more consistent with other `Code` flags. * Output anonymous classes when possible Anonymous classes can be output when: - The class has no parent. The current super compilation needs a class variable to reference. This condition will go away when ES2015 super is in use. - The class contains no bound static methods. Bound static methods have their context set to the class name. * Throw errors at compile time for async or generator constructors * Improve handling of anonymous classes Anonymous classes are now always anonymous. If a name is required (e.g. for bound static methods or derived classes) then the class is compiled in an `ExecutableClassBody` which will give the anonymous class a stable reference. * Add a `replaceInContext` method to `Node` `replaceInContext` will traverse children looking for a node for which `match` returns true. Once found, the matching node will be replaced by the result of calling `replacement`. * Separate `this` assignments from function parameters This change has been made to simplify two future changes: 1. Outputting `@`-param assignments after a `super` call. In this case it is necessary that non-`@` parameters are available before `super` is called, so destructuring has to happen before `this` assignment. 2. Compiling destructured assignment to ES6 In this case also destructuring has to happen before `this`, as destructuring can happen in the arguments list, but `this` assignment can not. A bonus side-effect is that default values for `@` params are now output as ES6 default parameters, e.g. (@a = 1) -> becomes function a (a = 1) { this.a = a; } * Change `super` handling in class constructors Inside an ES derived constructor (a constructor for a class that extends another class), it is impossible to access `this` until `super` has been called. This conflicts with CoffeeScript's `@`-param and bound method features, which compile to `this` references at the top of a function body. For example: class B extends A constructor: (@param) -> super method: => This would compile to something like: class B extends A { constructor (param) { this.param = param; this.method = bind(this.method, this); super(...arguments); } } This would break in an ES-compliant runtime as there are `this` references before the call to `super`. Before this commit we were dealing with this by injecting an implicit `super` call into derived constructors that do not already have an explicit `super` call. Furthermore, we would disallow explicit `super` calls in derived constructors that used bound methods or `@`-params, meaning the above example would need to be rewritten as: class B extends A constructor: (@param) -> method: => This would result in a call to `super(...arguments)` being generated as the first expression in `B#constructor`. Whilst this approach seems to work pretty well, and is arguably more convenient than having to manually call `super` when you don't particularly care about the arguments, it does introduce some 'magic' and separation from ES, and would likely be a pain point in a project that made use of significant constructor overriding. This commit introduces a mechanism through which `super` in constructors is 'expanded' to include any generated `this` assignments, whilst retaining the same semantics of a super call. The first example above now compiles to something like: class B extends A { constructor (param) { var ref ref = super(...arguments), this.param = param, this.method = bind(this.method, this), ref; } } * Improve `super` handling in constructors Rather than functions expanding their `super` calls, the `SuperCall` node can now be given a list of `thisAssignments` to apply when it is compiled. This allows us to use the normal compiler machinery to determine whether the `super` result needs to be cached, whether it appears inline or not, etc. * Fix anonymous classes at the top level Anonymous classes in ES are only valid within expressions. If an anonymous class is at the top level it will now be wrapped in parenthses to force it into an expression. * Re-add Parens wrapper around executable class bodies This was lost in the refactoring, but it necessary to ensure `new class ...` works as expected when there's an executable body. * Throw compiler errors for badly configured derived constructors Rather than letting them become runtime errors, the following checks are now performed when compiling a derived constructor: - The constructor **must** include a call to `super`. - The constructor **must not** reference `this` in the function body before `super` has been called. * Add some tests exercising new class behaviour - async methods in classes - `this` access after `super` in extended classes - constructor super in arrow functions - constructor functions can't be async - constructor functions can't be generators - derived constructors must call super - derived constructors can't reference `this` before calling super - generator methods in classes - 'new' target * Improve constructor `super` errors Add a check for `super` in non-extended class constructors, and explicitly mention derived constructors in the "can't reference this before super" error. * Fix compilation of multiple `super` paths in derived constructors `super` can only be called once, but it can be called conditionally from multiple locations. The chosen fix is to add the `this` assignments to every super call. * Additional class tests, added as a separate file to simplify testing and merging. Some methods are commented out because they currently throw and I'm not sure how to test for compilation errors like those. There is also one test which I deliberately left without passing, `super` in an external prototype override. This test should 'pass' but is really a variation on the failing `super only allowed in an instance method` tests above it. * Changes to the tests. Found bug in super in prototype method. fixed. * Added failing test back in, dealing with bound functions in external prototype overrides. * Located a bug in the compiler relating to assertions and escaped ES6 classes. * Move tests from classes-additional.coffee into classes.coffee; comment out console.log * Cleaned up tests and made changes based on feedback. Test at the end still has issues, but it's commented out for now. * Make HoistTarget.expand recursive It's possible that a hoisted node may itself contain hoisted nodes (e.g. a class method inside a class method). For this to work the hoisted fragments need to be expanded recursively. * Uncomment final test in classes.coffee The test case now compiles, however another issue is affecting the test due to the error for `this` before `super` triggering based on source order rather than execution order. These have been commented out for now. * Fixed last test TODOs in test/classes.coffee Turns out an expression like `this.foo = super()` won't run in JS as it attempts to lookup `this` before evaluating `super` (i.e. throws "this is not defined"). * Added more tests for compatability checks, statics, prototypes and ES6 expectations. Cleaned test "nested classes with super". * Changes to reflect feedback and to comment out issues that will be addressed seperately. * Clean up test/classes.coffee - Trim trailing whitespace. - Rephrase a condition to be more idiomatic. * Remove check for `super` in derived constructors In order to be usable at runtime, an extended ES class must call `super` OR return an alternative object. This check prevented the latter case, and checking for an alternative return can't be completed statically without control flow analysis. * Disallow 'super' in constructor parameter defaults There are many edge cases when combining 'super' in parameter defaults with @-parameters and bound functions (and potentially property initializers in the future). Rather than attempting to resolve these edge cases, 'super' is now explicitly disallowed in constructor parameter defaults. * Disallow @-params in derived constructors without 'super' @-parameters can't be assigned unless 'super' is called.
2017-01-13 00:55:30 -05:00
new Test true, nonce
new Test false, nonce
test "`@`-params and bound methods with multiple `super` paths (expressions)", ->
nonce = {}
class Base
constructor: (@name) ->
class Test extends Base
constructor: (param, @param) ->
# Contrived example: force each path into an expression with inline assertions
if param
result = (
eq (super 'param'), @;
eq @name, 'param';
eq @param, nonce;
ok @method isnt Test::method
[CS2] Compile class constructors to ES2015 classes (#4354) * Compile classes to ES2015 classes Rather than compiling classes to named functions with prototype and class assignments, they are now compiled to ES2015 class declarations. Backwards compatibility has been maintained by compiling ES2015- incompatible properties as prototype or class assignments. `super` continues to be compiled as before. Where possible, classes will be compiled "bare", without an enclosing IIFE. This is possible when the class contains only ES2015 compatible expressions (methods and static methods), and has no parent (this last constraint is a result of the legacy `super` compilation, and could be removed once ES2015 `super` is being used). Classes are still assigned to variables to maintain compatibility for assigned class expressions. There are a few changes to existing functionality that could break backwards compatibility: - Derived constructors that deliberately don't call `super` are no longer possible. ES2015 derived classes can't use `this` unless the parent constructor has been called, so it's now called implicitly when not present. - As a consequence of the above, derived constructors with @ parameters or bound methods and explicit `super` calls are not allowed. The implicit `super` must be used in these cases. * Add tests to verify class interoperability with ES * Refactor class nodes to separate executable body logic Logic has been redistributed amongst the class nodes so that: - `Class` contains the logic necessary to compile an ES class declaration. - `ExecutableClassBody` contains the logic necessary to compile CS' class extensions that require an executable class body. `Class` still necessarily contains logic to determine whether an expression is valid in an ES class initializer or not. If any invalid expressions are found then `Class` will wrap itself in an `ExecutableClassBody` when compiling. * Rename `Code#static` to `Code#isStatic` This naming is more consistent with other `Code` flags. * Output anonymous classes when possible Anonymous classes can be output when: - The class has no parent. The current super compilation needs a class variable to reference. This condition will go away when ES2015 super is in use. - The class contains no bound static methods. Bound static methods have their context set to the class name. * Throw errors at compile time for async or generator constructors * Improve handling of anonymous classes Anonymous classes are now always anonymous. If a name is required (e.g. for bound static methods or derived classes) then the class is compiled in an `ExecutableClassBody` which will give the anonymous class a stable reference. * Add a `replaceInContext` method to `Node` `replaceInContext` will traverse children looking for a node for which `match` returns true. Once found, the matching node will be replaced by the result of calling `replacement`. * Separate `this` assignments from function parameters This change has been made to simplify two future changes: 1. Outputting `@`-param assignments after a `super` call. In this case it is necessary that non-`@` parameters are available before `super` is called, so destructuring has to happen before `this` assignment. 2. Compiling destructured assignment to ES6 In this case also destructuring has to happen before `this`, as destructuring can happen in the arguments list, but `this` assignment can not. A bonus side-effect is that default values for `@` params are now output as ES6 default parameters, e.g. (@a = 1) -> becomes function a (a = 1) { this.a = a; } * Change `super` handling in class constructors Inside an ES derived constructor (a constructor for a class that extends another class), it is impossible to access `this` until `super` has been called. This conflicts with CoffeeScript's `@`-param and bound method features, which compile to `this` references at the top of a function body. For example: class B extends A constructor: (@param) -> super method: => This would compile to something like: class B extends A { constructor (param) { this.param = param; this.method = bind(this.method, this); super(...arguments); } } This would break in an ES-compliant runtime as there are `this` references before the call to `super`. Before this commit we were dealing with this by injecting an implicit `super` call into derived constructors that do not already have an explicit `super` call. Furthermore, we would disallow explicit `super` calls in derived constructors that used bound methods or `@`-params, meaning the above example would need to be rewritten as: class B extends A constructor: (@param) -> method: => This would result in a call to `super(...arguments)` being generated as the first expression in `B#constructor`. Whilst this approach seems to work pretty well, and is arguably more convenient than having to manually call `super` when you don't particularly care about the arguments, it does introduce some 'magic' and separation from ES, and would likely be a pain point in a project that made use of significant constructor overriding. This commit introduces a mechanism through which `super` in constructors is 'expanded' to include any generated `this` assignments, whilst retaining the same semantics of a super call. The first example above now compiles to something like: class B extends A { constructor (param) { var ref ref = super(...arguments), this.param = param, this.method = bind(this.method, this), ref; } } * Improve `super` handling in constructors Rather than functions expanding their `super` calls, the `SuperCall` node can now be given a list of `thisAssignments` to apply when it is compiled. This allows us to use the normal compiler machinery to determine whether the `super` result needs to be cached, whether it appears inline or not, etc. * Fix anonymous classes at the top level Anonymous classes in ES are only valid within expressions. If an anonymous class is at the top level it will now be wrapped in parenthses to force it into an expression. * Re-add Parens wrapper around executable class bodies This was lost in the refactoring, but it necessary to ensure `new class ...` works as expected when there's an executable body. * Throw compiler errors for badly configured derived constructors Rather than letting them become runtime errors, the following checks are now performed when compiling a derived constructor: - The constructor **must** include a call to `super`. - The constructor **must not** reference `this` in the function body before `super` has been called. * Add some tests exercising new class behaviour - async methods in classes - `this` access after `super` in extended classes - constructor super in arrow functions - constructor functions can't be async - constructor functions can't be generators - derived constructors must call super - derived constructors can't reference `this` before calling super - generator methods in classes - 'new' target * Improve constructor `super` errors Add a check for `super` in non-extended class constructors, and explicitly mention derived constructors in the "can't reference this before super" error. * Fix compilation of multiple `super` paths in derived constructors `super` can only be called once, but it can be called conditionally from multiple locations. The chosen fix is to add the `this` assignments to every super call. * Additional class tests, added as a separate file to simplify testing and merging. Some methods are commented out because they currently throw and I'm not sure how to test for compilation errors like those. There is also one test which I deliberately left without passing, `super` in an external prototype override. This test should 'pass' but is really a variation on the failing `super only allowed in an instance method` tests above it. * Changes to the tests. Found bug in super in prototype method. fixed. * Added failing test back in, dealing with bound functions in external prototype overrides. * Located a bug in the compiler relating to assertions and escaped ES6 classes. * Move tests from classes-additional.coffee into classes.coffee; comment out console.log * Cleaned up tests and made changes based on feedback. Test at the end still has issues, but it's commented out for now. * Make HoistTarget.expand recursive It's possible that a hoisted node may itself contain hoisted nodes (e.g. a class method inside a class method). For this to work the hoisted fragments need to be expanded recursively. * Uncomment final test in classes.coffee The test case now compiles, however another issue is affecting the test due to the error for `this` before `super` triggering based on source order rather than execution order. These have been commented out for now. * Fixed last test TODOs in test/classes.coffee Turns out an expression like `this.foo = super()` won't run in JS as it attempts to lookup `this` before evaluating `super` (i.e. throws "this is not defined"). * Added more tests for compatability checks, statics, prototypes and ES6 expectations. Cleaned test "nested classes with super". * Changes to reflect feedback and to comment out issues that will be addressed seperately. * Clean up test/classes.coffee - Trim trailing whitespace. - Rephrase a condition to be more idiomatic. * Remove check for `super` in derived constructors In order to be usable at runtime, an extended ES class must call `super` OR return an alternative object. This check prevented the latter case, and checking for an alternative return can't be completed statically without control flow analysis. * Disallow 'super' in constructor parameter defaults There are many edge cases when combining 'super' in parameter defaults with @-parameters and bound functions (and potentially property initializers in the future). Rather than attempting to resolve these edge cases, 'super' is now explicitly disallowed in constructor parameter defaults. * Disallow @-params in derived constructors without 'super' @-parameters can't be assigned unless 'super' is called.
2017-01-13 00:55:30 -05:00
)
else
result = (
eq (super 'not param'), @;
eq @name, 'not param';
eq @param, nonce;
ok @method isnt Test::method
[CS2] Compile class constructors to ES2015 classes (#4354) * Compile classes to ES2015 classes Rather than compiling classes to named functions with prototype and class assignments, they are now compiled to ES2015 class declarations. Backwards compatibility has been maintained by compiling ES2015- incompatible properties as prototype or class assignments. `super` continues to be compiled as before. Where possible, classes will be compiled "bare", without an enclosing IIFE. This is possible when the class contains only ES2015 compatible expressions (methods and static methods), and has no parent (this last constraint is a result of the legacy `super` compilation, and could be removed once ES2015 `super` is being used). Classes are still assigned to variables to maintain compatibility for assigned class expressions. There are a few changes to existing functionality that could break backwards compatibility: - Derived constructors that deliberately don't call `super` are no longer possible. ES2015 derived classes can't use `this` unless the parent constructor has been called, so it's now called implicitly when not present. - As a consequence of the above, derived constructors with @ parameters or bound methods and explicit `super` calls are not allowed. The implicit `super` must be used in these cases. * Add tests to verify class interoperability with ES * Refactor class nodes to separate executable body logic Logic has been redistributed amongst the class nodes so that: - `Class` contains the logic necessary to compile an ES class declaration. - `ExecutableClassBody` contains the logic necessary to compile CS' class extensions that require an executable class body. `Class` still necessarily contains logic to determine whether an expression is valid in an ES class initializer or not. If any invalid expressions are found then `Class` will wrap itself in an `ExecutableClassBody` when compiling. * Rename `Code#static` to `Code#isStatic` This naming is more consistent with other `Code` flags. * Output anonymous classes when possible Anonymous classes can be output when: - The class has no parent. The current super compilation needs a class variable to reference. This condition will go away when ES2015 super is in use. - The class contains no bound static methods. Bound static methods have their context set to the class name. * Throw errors at compile time for async or generator constructors * Improve handling of anonymous classes Anonymous classes are now always anonymous. If a name is required (e.g. for bound static methods or derived classes) then the class is compiled in an `ExecutableClassBody` which will give the anonymous class a stable reference. * Add a `replaceInContext` method to `Node` `replaceInContext` will traverse children looking for a node for which `match` returns true. Once found, the matching node will be replaced by the result of calling `replacement`. * Separate `this` assignments from function parameters This change has been made to simplify two future changes: 1. Outputting `@`-param assignments after a `super` call. In this case it is necessary that non-`@` parameters are available before `super` is called, so destructuring has to happen before `this` assignment. 2. Compiling destructured assignment to ES6 In this case also destructuring has to happen before `this`, as destructuring can happen in the arguments list, but `this` assignment can not. A bonus side-effect is that default values for `@` params are now output as ES6 default parameters, e.g. (@a = 1) -> becomes function a (a = 1) { this.a = a; } * Change `super` handling in class constructors Inside an ES derived constructor (a constructor for a class that extends another class), it is impossible to access `this` until `super` has been called. This conflicts with CoffeeScript's `@`-param and bound method features, which compile to `this` references at the top of a function body. For example: class B extends A constructor: (@param) -> super method: => This would compile to something like: class B extends A { constructor (param) { this.param = param; this.method = bind(this.method, this); super(...arguments); } } This would break in an ES-compliant runtime as there are `this` references before the call to `super`. Before this commit we were dealing with this by injecting an implicit `super` call into derived constructors that do not already have an explicit `super` call. Furthermore, we would disallow explicit `super` calls in derived constructors that used bound methods or `@`-params, meaning the above example would need to be rewritten as: class B extends A constructor: (@param) -> method: => This would result in a call to `super(...arguments)` being generated as the first expression in `B#constructor`. Whilst this approach seems to work pretty well, and is arguably more convenient than having to manually call `super` when you don't particularly care about the arguments, it does introduce some 'magic' and separation from ES, and would likely be a pain point in a project that made use of significant constructor overriding. This commit introduces a mechanism through which `super` in constructors is 'expanded' to include any generated `this` assignments, whilst retaining the same semantics of a super call. The first example above now compiles to something like: class B extends A { constructor (param) { var ref ref = super(...arguments), this.param = param, this.method = bind(this.method, this), ref; } } * Improve `super` handling in constructors Rather than functions expanding their `super` calls, the `SuperCall` node can now be given a list of `thisAssignments` to apply when it is compiled. This allows us to use the normal compiler machinery to determine whether the `super` result needs to be cached, whether it appears inline or not, etc. * Fix anonymous classes at the top level Anonymous classes in ES are only valid within expressions. If an anonymous class is at the top level it will now be wrapped in parenthses to force it into an expression. * Re-add Parens wrapper around executable class bodies This was lost in the refactoring, but it necessary to ensure `new class ...` works as expected when there's an executable body. * Throw compiler errors for badly configured derived constructors Rather than letting them become runtime errors, the following checks are now performed when compiling a derived constructor: - The constructor **must** include a call to `super`. - The constructor **must not** reference `this` in the function body before `super` has been called. * Add some tests exercising new class behaviour - async methods in classes - `this` access after `super` in extended classes - constructor super in arrow functions - constructor functions can't be async - constructor functions can't be generators - derived constructors must call super - derived constructors can't reference `this` before calling super - generator methods in classes - 'new' target * Improve constructor `super` errors Add a check for `super` in non-extended class constructors, and explicitly mention derived constructors in the "can't reference this before super" error. * Fix compilation of multiple `super` paths in derived constructors `super` can only be called once, but it can be called conditionally from multiple locations. The chosen fix is to add the `this` assignments to every super call. * Additional class tests, added as a separate file to simplify testing and merging. Some methods are commented out because they currently throw and I'm not sure how to test for compilation errors like those. There is also one test which I deliberately left without passing, `super` in an external prototype override. This test should 'pass' but is really a variation on the failing `super only allowed in an instance method` tests above it. * Changes to the tests. Found bug in super in prototype method. fixed. * Added failing test back in, dealing with bound functions in external prototype overrides. * Located a bug in the compiler relating to assertions and escaped ES6 classes. * Move tests from classes-additional.coffee into classes.coffee; comment out console.log * Cleaned up tests and made changes based on feedback. Test at the end still has issues, but it's commented out for now. * Make HoistTarget.expand recursive It's possible that a hoisted node may itself contain hoisted nodes (e.g. a class method inside a class method). For this to work the hoisted fragments need to be expanded recursively. * Uncomment final test in classes.coffee The test case now compiles, however another issue is affecting the test due to the error for `this` before `super` triggering based on source order rather than execution order. These have been commented out for now. * Fixed last test TODOs in test/classes.coffee Turns out an expression like `this.foo = super()` won't run in JS as it attempts to lookup `this` before evaluating `super` (i.e. throws "this is not defined"). * Added more tests for compatability checks, statics, prototypes and ES6 expectations. Cleaned test "nested classes with super". * Changes to reflect feedback and to comment out issues that will be addressed seperately. * Clean up test/classes.coffee - Trim trailing whitespace. - Rephrase a condition to be more idiomatic. * Remove check for `super` in derived constructors In order to be usable at runtime, an extended ES class must call `super` OR return an alternative object. This check prevented the latter case, and checking for an alternative return can't be completed statically without control flow analysis. * Disallow 'super' in constructor parameter defaults There are many edge cases when combining 'super' in parameter defaults with @-parameters and bound functions (and potentially property initializers in the future). Rather than attempting to resolve these edge cases, 'super' is now explicitly disallowed in constructor parameter defaults. * Disallow @-params in derived constructors without 'super' @-parameters can't be assigned unless 'super' is called.
2017-01-13 00:55:30 -05:00
)
method: =>
[CS2] Compile class constructors to ES2015 classes (#4354) * Compile classes to ES2015 classes Rather than compiling classes to named functions with prototype and class assignments, they are now compiled to ES2015 class declarations. Backwards compatibility has been maintained by compiling ES2015- incompatible properties as prototype or class assignments. `super` continues to be compiled as before. Where possible, classes will be compiled "bare", without an enclosing IIFE. This is possible when the class contains only ES2015 compatible expressions (methods and static methods), and has no parent (this last constraint is a result of the legacy `super` compilation, and could be removed once ES2015 `super` is being used). Classes are still assigned to variables to maintain compatibility for assigned class expressions. There are a few changes to existing functionality that could break backwards compatibility: - Derived constructors that deliberately don't call `super` are no longer possible. ES2015 derived classes can't use `this` unless the parent constructor has been called, so it's now called implicitly when not present. - As a consequence of the above, derived constructors with @ parameters or bound methods and explicit `super` calls are not allowed. The implicit `super` must be used in these cases. * Add tests to verify class interoperability with ES * Refactor class nodes to separate executable body logic Logic has been redistributed amongst the class nodes so that: - `Class` contains the logic necessary to compile an ES class declaration. - `ExecutableClassBody` contains the logic necessary to compile CS' class extensions that require an executable class body. `Class` still necessarily contains logic to determine whether an expression is valid in an ES class initializer or not. If any invalid expressions are found then `Class` will wrap itself in an `ExecutableClassBody` when compiling. * Rename `Code#static` to `Code#isStatic` This naming is more consistent with other `Code` flags. * Output anonymous classes when possible Anonymous classes can be output when: - The class has no parent. The current super compilation needs a class variable to reference. This condition will go away when ES2015 super is in use. - The class contains no bound static methods. Bound static methods have their context set to the class name. * Throw errors at compile time for async or generator constructors * Improve handling of anonymous classes Anonymous classes are now always anonymous. If a name is required (e.g. for bound static methods or derived classes) then the class is compiled in an `ExecutableClassBody` which will give the anonymous class a stable reference. * Add a `replaceInContext` method to `Node` `replaceInContext` will traverse children looking for a node for which `match` returns true. Once found, the matching node will be replaced by the result of calling `replacement`. * Separate `this` assignments from function parameters This change has been made to simplify two future changes: 1. Outputting `@`-param assignments after a `super` call. In this case it is necessary that non-`@` parameters are available before `super` is called, so destructuring has to happen before `this` assignment. 2. Compiling destructured assignment to ES6 In this case also destructuring has to happen before `this`, as destructuring can happen in the arguments list, but `this` assignment can not. A bonus side-effect is that default values for `@` params are now output as ES6 default parameters, e.g. (@a = 1) -> becomes function a (a = 1) { this.a = a; } * Change `super` handling in class constructors Inside an ES derived constructor (a constructor for a class that extends another class), it is impossible to access `this` until `super` has been called. This conflicts with CoffeeScript's `@`-param and bound method features, which compile to `this` references at the top of a function body. For example: class B extends A constructor: (@param) -> super method: => This would compile to something like: class B extends A { constructor (param) { this.param = param; this.method = bind(this.method, this); super(...arguments); } } This would break in an ES-compliant runtime as there are `this` references before the call to `super`. Before this commit we were dealing with this by injecting an implicit `super` call into derived constructors that do not already have an explicit `super` call. Furthermore, we would disallow explicit `super` calls in derived constructors that used bound methods or `@`-params, meaning the above example would need to be rewritten as: class B extends A constructor: (@param) -> method: => This would result in a call to `super(...arguments)` being generated as the first expression in `B#constructor`. Whilst this approach seems to work pretty well, and is arguably more convenient than having to manually call `super` when you don't particularly care about the arguments, it does introduce some 'magic' and separation from ES, and would likely be a pain point in a project that made use of significant constructor overriding. This commit introduces a mechanism through which `super` in constructors is 'expanded' to include any generated `this` assignments, whilst retaining the same semantics of a super call. The first example above now compiles to something like: class B extends A { constructor (param) { var ref ref = super(...arguments), this.param = param, this.method = bind(this.method, this), ref; } } * Improve `super` handling in constructors Rather than functions expanding their `super` calls, the `SuperCall` node can now be given a list of `thisAssignments` to apply when it is compiled. This allows us to use the normal compiler machinery to determine whether the `super` result needs to be cached, whether it appears inline or not, etc. * Fix anonymous classes at the top level Anonymous classes in ES are only valid within expressions. If an anonymous class is at the top level it will now be wrapped in parenthses to force it into an expression. * Re-add Parens wrapper around executable class bodies This was lost in the refactoring, but it necessary to ensure `new class ...` works as expected when there's an executable body. * Throw compiler errors for badly configured derived constructors Rather than letting them become runtime errors, the following checks are now performed when compiling a derived constructor: - The constructor **must** include a call to `super`. - The constructor **must not** reference `this` in the function body before `super` has been called. * Add some tests exercising new class behaviour - async methods in classes - `this` access after `super` in extended classes - constructor super in arrow functions - constructor functions can't be async - constructor functions can't be generators - derived constructors must call super - derived constructors can't reference `this` before calling super - generator methods in classes - 'new' target * Improve constructor `super` errors Add a check for `super` in non-extended class constructors, and explicitly mention derived constructors in the "can't reference this before super" error. * Fix compilation of multiple `super` paths in derived constructors `super` can only be called once, but it can be called conditionally from multiple locations. The chosen fix is to add the `this` assignments to every super call. * Additional class tests, added as a separate file to simplify testing and merging. Some methods are commented out because they currently throw and I'm not sure how to test for compilation errors like those. There is also one test which I deliberately left without passing, `super` in an external prototype override. This test should 'pass' but is really a variation on the failing `super only allowed in an instance method` tests above it. * Changes to the tests. Found bug in super in prototype method. fixed. * Added failing test back in, dealing with bound functions in external prototype overrides. * Located a bug in the compiler relating to assertions and escaped ES6 classes. * Move tests from classes-additional.coffee into classes.coffee; comment out console.log * Cleaned up tests and made changes based on feedback. Test at the end still has issues, but it's commented out for now. * Make HoistTarget.expand recursive It's possible that a hoisted node may itself contain hoisted nodes (e.g. a class method inside a class method). For this to work the hoisted fragments need to be expanded recursively. * Uncomment final test in classes.coffee The test case now compiles, however another issue is affecting the test due to the error for `this` before `super` triggering based on source order rather than execution order. These have been commented out for now. * Fixed last test TODOs in test/classes.coffee Turns out an expression like `this.foo = super()` won't run in JS as it attempts to lookup `this` before evaluating `super` (i.e. throws "this is not defined"). * Added more tests for compatability checks, statics, prototypes and ES6 expectations. Cleaned test "nested classes with super". * Changes to reflect feedback and to comment out issues that will be addressed seperately. * Clean up test/classes.coffee - Trim trailing whitespace. - Rephrase a condition to be more idiomatic. * Remove check for `super` in derived constructors In order to be usable at runtime, an extended ES class must call `super` OR return an alternative object. This check prevented the latter case, and checking for an alternative return can't be completed statically without control flow analysis. * Disallow 'super' in constructor parameter defaults There are many edge cases when combining 'super' in parameter defaults with @-parameters and bound functions (and potentially property initializers in the future). Rather than attempting to resolve these edge cases, 'super' is now explicitly disallowed in constructor parameter defaults. * Disallow @-params in derived constructors without 'super' @-parameters can't be assigned unless 'super' is called.
2017-01-13 00:55:30 -05:00
new Test true, nonce
new Test false, nonce
test "constructor super in arrow functions", ->
class Test extends (class)
constructor: (@param) ->
[CS2] Compile all super calls to ES2015 super (#4424) * Compile all super calls to ES2015 super This breaks using `super` in non-methods, meaning several tests are failing. Self-compilation still works. * Use bound functions for IIFEs containing `super` `super` can only be called directly in a method, or in an arrow function. * Fix handling of `class @A extends A` This behaviour worked 'for free' when the parent reference was being cached by the executable class body wrapper. There now needs to be special handling in place to check if the parent name matches the class name, and if so to cache the parent reference. * Fix tests broken by compiling ES2015 `super` * Disallow bare super This removes syntax support for 'bare' super calls, e.g.: class B extends A constructor: -> super `super` must now always be followed with arguments like a regular function call. This also removes the capability of implicitly forwarding arguments. The above can be equivalently be written as: class B extends A constructor: -> super arguments... * Support super with accessors `super` with following accessor(s) is now compiled to ES2015 equivalents. In particular, expressions such as `super.name`, `super[name]`, and also `super.name.prop` are all now valid, and can be used as expected as calls (i.e. `super.name()`) or in expressions (i.e. `if super.name? ...`). `super` without accessors is compiled to a constructor super call in a constructor, and otherwise, as before, to a super call to the method of the same name, i.e. speak: -> super() ...is equivalent to speak: -> super.speak() A neat side-effect of the changes is that existential calls now work properly with super, meaning `super?()` will only call if the super property exists (and is a function). This is not valid for super in constructors. * Prevent calling `super` methods with `new` This fixes a bug in the previous super handling whereby using the `new` operator with a `super` call would silently drop the `new`. This is now an explicit compiler error, as it is invalid JS at runtime. * Clean up some old super handling code This was mostly code for tracking the source classes and variables for methods, which were needed to build the old lookups on `__super__`. * Add TODO to improve bare super parse error * Add some TODOs to improve some of the class tests
2017-02-04 15:03:17 -05:00
do => super()
[CS2] Compile class constructors to ES2015 classes (#4354) * Compile classes to ES2015 classes Rather than compiling classes to named functions with prototype and class assignments, they are now compiled to ES2015 class declarations. Backwards compatibility has been maintained by compiling ES2015- incompatible properties as prototype or class assignments. `super` continues to be compiled as before. Where possible, classes will be compiled "bare", without an enclosing IIFE. This is possible when the class contains only ES2015 compatible expressions (methods and static methods), and has no parent (this last constraint is a result of the legacy `super` compilation, and could be removed once ES2015 `super` is being used). Classes are still assigned to variables to maintain compatibility for assigned class expressions. There are a few changes to existing functionality that could break backwards compatibility: - Derived constructors that deliberately don't call `super` are no longer possible. ES2015 derived classes can't use `this` unless the parent constructor has been called, so it's now called implicitly when not present. - As a consequence of the above, derived constructors with @ parameters or bound methods and explicit `super` calls are not allowed. The implicit `super` must be used in these cases. * Add tests to verify class interoperability with ES * Refactor class nodes to separate executable body logic Logic has been redistributed amongst the class nodes so that: - `Class` contains the logic necessary to compile an ES class declaration. - `ExecutableClassBody` contains the logic necessary to compile CS' class extensions that require an executable class body. `Class` still necessarily contains logic to determine whether an expression is valid in an ES class initializer or not. If any invalid expressions are found then `Class` will wrap itself in an `ExecutableClassBody` when compiling. * Rename `Code#static` to `Code#isStatic` This naming is more consistent with other `Code` flags. * Output anonymous classes when possible Anonymous classes can be output when: - The class has no parent. The current super compilation needs a class variable to reference. This condition will go away when ES2015 super is in use. - The class contains no bound static methods. Bound static methods have their context set to the class name. * Throw errors at compile time for async or generator constructors * Improve handling of anonymous classes Anonymous classes are now always anonymous. If a name is required (e.g. for bound static methods or derived classes) then the class is compiled in an `ExecutableClassBody` which will give the anonymous class a stable reference. * Add a `replaceInContext` method to `Node` `replaceInContext` will traverse children looking for a node for which `match` returns true. Once found, the matching node will be replaced by the result of calling `replacement`. * Separate `this` assignments from function parameters This change has been made to simplify two future changes: 1. Outputting `@`-param assignments after a `super` call. In this case it is necessary that non-`@` parameters are available before `super` is called, so destructuring has to happen before `this` assignment. 2. Compiling destructured assignment to ES6 In this case also destructuring has to happen before `this`, as destructuring can happen in the arguments list, but `this` assignment can not. A bonus side-effect is that default values for `@` params are now output as ES6 default parameters, e.g. (@a = 1) -> becomes function a (a = 1) { this.a = a; } * Change `super` handling in class constructors Inside an ES derived constructor (a constructor for a class that extends another class), it is impossible to access `this` until `super` has been called. This conflicts with CoffeeScript's `@`-param and bound method features, which compile to `this` references at the top of a function body. For example: class B extends A constructor: (@param) -> super method: => This would compile to something like: class B extends A { constructor (param) { this.param = param; this.method = bind(this.method, this); super(...arguments); } } This would break in an ES-compliant runtime as there are `this` references before the call to `super`. Before this commit we were dealing with this by injecting an implicit `super` call into derived constructors that do not already have an explicit `super` call. Furthermore, we would disallow explicit `super` calls in derived constructors that used bound methods or `@`-params, meaning the above example would need to be rewritten as: class B extends A constructor: (@param) -> method: => This would result in a call to `super(...arguments)` being generated as the first expression in `B#constructor`. Whilst this approach seems to work pretty well, and is arguably more convenient than having to manually call `super` when you don't particularly care about the arguments, it does introduce some 'magic' and separation from ES, and would likely be a pain point in a project that made use of significant constructor overriding. This commit introduces a mechanism through which `super` in constructors is 'expanded' to include any generated `this` assignments, whilst retaining the same semantics of a super call. The first example above now compiles to something like: class B extends A { constructor (param) { var ref ref = super(...arguments), this.param = param, this.method = bind(this.method, this), ref; } } * Improve `super` handling in constructors Rather than functions expanding their `super` calls, the `SuperCall` node can now be given a list of `thisAssignments` to apply when it is compiled. This allows us to use the normal compiler machinery to determine whether the `super` result needs to be cached, whether it appears inline or not, etc. * Fix anonymous classes at the top level Anonymous classes in ES are only valid within expressions. If an anonymous class is at the top level it will now be wrapped in parenthses to force it into an expression. * Re-add Parens wrapper around executable class bodies This was lost in the refactoring, but it necessary to ensure `new class ...` works as expected when there's an executable body. * Throw compiler errors for badly configured derived constructors Rather than letting them become runtime errors, the following checks are now performed when compiling a derived constructor: - The constructor **must** include a call to `super`. - The constructor **must not** reference `this` in the function body before `super` has been called. * Add some tests exercising new class behaviour - async methods in classes - `this` access after `super` in extended classes - constructor super in arrow functions - constructor functions can't be async - constructor functions can't be generators - derived constructors must call super - derived constructors can't reference `this` before calling super - generator methods in classes - 'new' target * Improve constructor `super` errors Add a check for `super` in non-extended class constructors, and explicitly mention derived constructors in the "can't reference this before super" error. * Fix compilation of multiple `super` paths in derived constructors `super` can only be called once, but it can be called conditionally from multiple locations. The chosen fix is to add the `this` assignments to every super call. * Additional class tests, added as a separate file to simplify testing and merging. Some methods are commented out because they currently throw and I'm not sure how to test for compilation errors like those. There is also one test which I deliberately left without passing, `super` in an external prototype override. This test should 'pass' but is really a variation on the failing `super only allowed in an instance method` tests above it. * Changes to the tests. Found bug in super in prototype method. fixed. * Added failing test back in, dealing with bound functions in external prototype overrides. * Located a bug in the compiler relating to assertions and escaped ES6 classes. * Move tests from classes-additional.coffee into classes.coffee; comment out console.log * Cleaned up tests and made changes based on feedback. Test at the end still has issues, but it's commented out for now. * Make HoistTarget.expand recursive It's possible that a hoisted node may itself contain hoisted nodes (e.g. a class method inside a class method). For this to work the hoisted fragments need to be expanded recursively. * Uncomment final test in classes.coffee The test case now compiles, however another issue is affecting the test due to the error for `this` before `super` triggering based on source order rather than execution order. These have been commented out for now. * Fixed last test TODOs in test/classes.coffee Turns out an expression like `this.foo = super()` won't run in JS as it attempts to lookup `this` before evaluating `super` (i.e. throws "this is not defined"). * Added more tests for compatability checks, statics, prototypes and ES6 expectations. Cleaned test "nested classes with super". * Changes to reflect feedback and to comment out issues that will be addressed seperately. * Clean up test/classes.coffee - Trim trailing whitespace. - Rephrase a condition to be more idiomatic. * Remove check for `super` in derived constructors In order to be usable at runtime, an extended ES class must call `super` OR return an alternative object. This check prevented the latter case, and checking for an alternative return can't be completed statically without control flow analysis. * Disallow 'super' in constructor parameter defaults There are many edge cases when combining 'super' in parameter defaults with @-parameters and bound functions (and potentially property initializers in the future). Rather than attempting to resolve these edge cases, 'super' is now explicitly disallowed in constructor parameter defaults. * Disallow @-params in derived constructors without 'super' @-parameters can't be assigned unless 'super' is called.
2017-01-13 00:55:30 -05:00
eq @param, nonce
new Test nonce = {}
[CS2] Compile all super calls to ES2015 super (#4424) * Compile all super calls to ES2015 super This breaks using `super` in non-methods, meaning several tests are failing. Self-compilation still works. * Use bound functions for IIFEs containing `super` `super` can only be called directly in a method, or in an arrow function. * Fix handling of `class @A extends A` This behaviour worked 'for free' when the parent reference was being cached by the executable class body wrapper. There now needs to be special handling in place to check if the parent name matches the class name, and if so to cache the parent reference. * Fix tests broken by compiling ES2015 `super` * Disallow bare super This removes syntax support for 'bare' super calls, e.g.: class B extends A constructor: -> super `super` must now always be followed with arguments like a regular function call. This also removes the capability of implicitly forwarding arguments. The above can be equivalently be written as: class B extends A constructor: -> super arguments... * Support super with accessors `super` with following accessor(s) is now compiled to ES2015 equivalents. In particular, expressions such as `super.name`, `super[name]`, and also `super.name.prop` are all now valid, and can be used as expected as calls (i.e. `super.name()`) or in expressions (i.e. `if super.name? ...`). `super` without accessors is compiled to a constructor super call in a constructor, and otherwise, as before, to a super call to the method of the same name, i.e. speak: -> super() ...is equivalent to speak: -> super.speak() A neat side-effect of the changes is that existential calls now work properly with super, meaning `super?()` will only call if the super property exists (and is a function). This is not valid for super in constructors. * Prevent calling `super` methods with `new` This fixes a bug in the previous super handling whereby using the `new` operator with a `super` call would silently drop the `new`. This is now an explicit compiler error, as it is invalid JS at runtime. * Clean up some old super handling code This was mostly code for tracking the source classes and variables for methods, which were needed to build the old lookups on `__super__`. * Add TODO to improve bare super parse error * Add some TODOs to improve some of the class tests
2017-02-04 15:03:17 -05:00
# TODO Some of these tests use CoffeeScript.compile and CoffeeScript.run when they could use
# regular test mechanics.
# TODO Some of these tests might be better placed in `test/error_messages.coffee`.
# TODO Some of these tests are duplicates.
[CS2] Compile class constructors to ES2015 classes (#4354) * Compile classes to ES2015 classes Rather than compiling classes to named functions with prototype and class assignments, they are now compiled to ES2015 class declarations. Backwards compatibility has been maintained by compiling ES2015- incompatible properties as prototype or class assignments. `super` continues to be compiled as before. Where possible, classes will be compiled "bare", without an enclosing IIFE. This is possible when the class contains only ES2015 compatible expressions (methods and static methods), and has no parent (this last constraint is a result of the legacy `super` compilation, and could be removed once ES2015 `super` is being used). Classes are still assigned to variables to maintain compatibility for assigned class expressions. There are a few changes to existing functionality that could break backwards compatibility: - Derived constructors that deliberately don't call `super` are no longer possible. ES2015 derived classes can't use `this` unless the parent constructor has been called, so it's now called implicitly when not present. - As a consequence of the above, derived constructors with @ parameters or bound methods and explicit `super` calls are not allowed. The implicit `super` must be used in these cases. * Add tests to verify class interoperability with ES * Refactor class nodes to separate executable body logic Logic has been redistributed amongst the class nodes so that: - `Class` contains the logic necessary to compile an ES class declaration. - `ExecutableClassBody` contains the logic necessary to compile CS' class extensions that require an executable class body. `Class` still necessarily contains logic to determine whether an expression is valid in an ES class initializer or not. If any invalid expressions are found then `Class` will wrap itself in an `ExecutableClassBody` when compiling. * Rename `Code#static` to `Code#isStatic` This naming is more consistent with other `Code` flags. * Output anonymous classes when possible Anonymous classes can be output when: - The class has no parent. The current super compilation needs a class variable to reference. This condition will go away when ES2015 super is in use. - The class contains no bound static methods. Bound static methods have their context set to the class name. * Throw errors at compile time for async or generator constructors * Improve handling of anonymous classes Anonymous classes are now always anonymous. If a name is required (e.g. for bound static methods or derived classes) then the class is compiled in an `ExecutableClassBody` which will give the anonymous class a stable reference. * Add a `replaceInContext` method to `Node` `replaceInContext` will traverse children looking for a node for which `match` returns true. Once found, the matching node will be replaced by the result of calling `replacement`. * Separate `this` assignments from function parameters This change has been made to simplify two future changes: 1. Outputting `@`-param assignments after a `super` call. In this case it is necessary that non-`@` parameters are available before `super` is called, so destructuring has to happen before `this` assignment. 2. Compiling destructured assignment to ES6 In this case also destructuring has to happen before `this`, as destructuring can happen in the arguments list, but `this` assignment can not. A bonus side-effect is that default values for `@` params are now output as ES6 default parameters, e.g. (@a = 1) -> becomes function a (a = 1) { this.a = a; } * Change `super` handling in class constructors Inside an ES derived constructor (a constructor for a class that extends another class), it is impossible to access `this` until `super` has been called. This conflicts with CoffeeScript's `@`-param and bound method features, which compile to `this` references at the top of a function body. For example: class B extends A constructor: (@param) -> super method: => This would compile to something like: class B extends A { constructor (param) { this.param = param; this.method = bind(this.method, this); super(...arguments); } } This would break in an ES-compliant runtime as there are `this` references before the call to `super`. Before this commit we were dealing with this by injecting an implicit `super` call into derived constructors that do not already have an explicit `super` call. Furthermore, we would disallow explicit `super` calls in derived constructors that used bound methods or `@`-params, meaning the above example would need to be rewritten as: class B extends A constructor: (@param) -> method: => This would result in a call to `super(...arguments)` being generated as the first expression in `B#constructor`. Whilst this approach seems to work pretty well, and is arguably more convenient than having to manually call `super` when you don't particularly care about the arguments, it does introduce some 'magic' and separation from ES, and would likely be a pain point in a project that made use of significant constructor overriding. This commit introduces a mechanism through which `super` in constructors is 'expanded' to include any generated `this` assignments, whilst retaining the same semantics of a super call. The first example above now compiles to something like: class B extends A { constructor (param) { var ref ref = super(...arguments), this.param = param, this.method = bind(this.method, this), ref; } } * Improve `super` handling in constructors Rather than functions expanding their `super` calls, the `SuperCall` node can now be given a list of `thisAssignments` to apply when it is compiled. This allows us to use the normal compiler machinery to determine whether the `super` result needs to be cached, whether it appears inline or not, etc. * Fix anonymous classes at the top level Anonymous classes in ES are only valid within expressions. If an anonymous class is at the top level it will now be wrapped in parenthses to force it into an expression. * Re-add Parens wrapper around executable class bodies This was lost in the refactoring, but it necessary to ensure `new class ...` works as expected when there's an executable body. * Throw compiler errors for badly configured derived constructors Rather than letting them become runtime errors, the following checks are now performed when compiling a derived constructor: - The constructor **must** include a call to `super`. - The constructor **must not** reference `this` in the function body before `super` has been called. * Add some tests exercising new class behaviour - async methods in classes - `this` access after `super` in extended classes - constructor super in arrow functions - constructor functions can't be async - constructor functions can't be generators - derived constructors must call super - derived constructors can't reference `this` before calling super - generator methods in classes - 'new' target * Improve constructor `super` errors Add a check for `super` in non-extended class constructors, and explicitly mention derived constructors in the "can't reference this before super" error. * Fix compilation of multiple `super` paths in derived constructors `super` can only be called once, but it can be called conditionally from multiple locations. The chosen fix is to add the `this` assignments to every super call. * Additional class tests, added as a separate file to simplify testing and merging. Some methods are commented out because they currently throw and I'm not sure how to test for compilation errors like those. There is also one test which I deliberately left without passing, `super` in an external prototype override. This test should 'pass' but is really a variation on the failing `super only allowed in an instance method` tests above it. * Changes to the tests. Found bug in super in prototype method. fixed. * Added failing test back in, dealing with bound functions in external prototype overrides. * Located a bug in the compiler relating to assertions and escaped ES6 classes. * Move tests from classes-additional.coffee into classes.coffee; comment out console.log * Cleaned up tests and made changes based on feedback. Test at the end still has issues, but it's commented out for now. * Make HoistTarget.expand recursive It's possible that a hoisted node may itself contain hoisted nodes (e.g. a class method inside a class method). For this to work the hoisted fragments need to be expanded recursively. * Uncomment final test in classes.coffee The test case now compiles, however another issue is affecting the test due to the error for `this` before `super` triggering based on source order rather than execution order. These have been commented out for now. * Fixed last test TODOs in test/classes.coffee Turns out an expression like `this.foo = super()` won't run in JS as it attempts to lookup `this` before evaluating `super` (i.e. throws "this is not defined"). * Added more tests for compatability checks, statics, prototypes and ES6 expectations. Cleaned test "nested classes with super". * Changes to reflect feedback and to comment out issues that will be addressed seperately. * Clean up test/classes.coffee - Trim trailing whitespace. - Rephrase a condition to be more idiomatic. * Remove check for `super` in derived constructors In order to be usable at runtime, an extended ES class must call `super` OR return an alternative object. This check prevented the latter case, and checking for an alternative return can't be completed statically without control flow analysis. * Disallow 'super' in constructor parameter defaults There are many edge cases when combining 'super' in parameter defaults with @-parameters and bound functions (and potentially property initializers in the future). Rather than attempting to resolve these edge cases, 'super' is now explicitly disallowed in constructor parameter defaults. * Disallow @-params in derived constructors without 'super' @-parameters can't be assigned unless 'super' is called.
2017-01-13 00:55:30 -05:00
# Ensure that we always throw if we experience more than one super()
# call in a constructor. This ends up being a runtime error.
# Should be caught at compile time.
test "multiple super calls", ->
throwsA = """
class A
constructor: (@drink) ->
make: -> "Making a #{@drink}"
class MultiSuper extends A
constructor: (drink) ->
super(drink)
super(drink)
@newDrink = drink
new MultiSuper('Late').make()
"""
throws -> CoffeeScript.run throwsA, bare: yes
# Basic test to ensure we can pass @params in a constuctor and
# inheritance works correctly
test "@ params", ->
class A
constructor: (@drink, @shots, @flavor) ->
make: -> "Making a #{@flavor} #{@drink} with #{@shots} shot(s)"
a = new A('Machiato', 2, 'chocolate')
eq a.make(), "Making a chocolate Machiato with 2 shot(s)"
class B extends A
b = new B('Machiato', 2, 'chocolate')
eq b.make(), "Making a chocolate Machiato with 2 shot(s)"
# Ensure we can accept @params with default parameters in a constructor
test "@ params with defaults in a constructor", ->
class A
# Multiple @ params with defaults
constructor: (@drink = 'Americano', @shots = '1', @flavor = 'caramel') ->
make: -> "Making a #{@flavor} #{@drink} with #{@shots} shot(s)"
a = new A()
eq a.make(), "Making a caramel Americano with 1 shot(s)"
# Ensure we can handle default constructors with class params
test "@ params with class params", ->
class Beverage
drink: 'Americano'
shots: '1'
flavor: 'caramel'
class A
# Class creation as a default param with `this`
constructor: (@drink = new Beverage()) ->
a = new A()
eq a.drink.drink, 'Americano'
beverage = new Beverage
class B
# class costruction with a default external param
constructor: (@drink = beverage) ->
b = new B()
eq b.drink.drink, 'Americano'
class C
# Default constructor with anonymous empty class
constructor: (@meta = class) ->
c = new C()
ok c.meta instanceof Function
test "@ params without super, including errors", ->
classA = """
class A
constructor: (@drink) ->
make: -> "Making a #{@drink}"
a = new A('Machiato')
"""
throwsB = """
class B extends A
#implied super
constructor: (@drink) ->
b = new B('Machiato')
"""
throwsCompileError classA + throwsB, bare: yes
[CS2] Compile class constructors to ES2015 classes (#4354) * Compile classes to ES2015 classes Rather than compiling classes to named functions with prototype and class assignments, they are now compiled to ES2015 class declarations. Backwards compatibility has been maintained by compiling ES2015- incompatible properties as prototype or class assignments. `super` continues to be compiled as before. Where possible, classes will be compiled "bare", without an enclosing IIFE. This is possible when the class contains only ES2015 compatible expressions (methods and static methods), and has no parent (this last constraint is a result of the legacy `super` compilation, and could be removed once ES2015 `super` is being used). Classes are still assigned to variables to maintain compatibility for assigned class expressions. There are a few changes to existing functionality that could break backwards compatibility: - Derived constructors that deliberately don't call `super` are no longer possible. ES2015 derived classes can't use `this` unless the parent constructor has been called, so it's now called implicitly when not present. - As a consequence of the above, derived constructors with @ parameters or bound methods and explicit `super` calls are not allowed. The implicit `super` must be used in these cases. * Add tests to verify class interoperability with ES * Refactor class nodes to separate executable body logic Logic has been redistributed amongst the class nodes so that: - `Class` contains the logic necessary to compile an ES class declaration. - `ExecutableClassBody` contains the logic necessary to compile CS' class extensions that require an executable class body. `Class` still necessarily contains logic to determine whether an expression is valid in an ES class initializer or not. If any invalid expressions are found then `Class` will wrap itself in an `ExecutableClassBody` when compiling. * Rename `Code#static` to `Code#isStatic` This naming is more consistent with other `Code` flags. * Output anonymous classes when possible Anonymous classes can be output when: - The class has no parent. The current super compilation needs a class variable to reference. This condition will go away when ES2015 super is in use. - The class contains no bound static methods. Bound static methods have their context set to the class name. * Throw errors at compile time for async or generator constructors * Improve handling of anonymous classes Anonymous classes are now always anonymous. If a name is required (e.g. for bound static methods or derived classes) then the class is compiled in an `ExecutableClassBody` which will give the anonymous class a stable reference. * Add a `replaceInContext` method to `Node` `replaceInContext` will traverse children looking for a node for which `match` returns true. Once found, the matching node will be replaced by the result of calling `replacement`. * Separate `this` assignments from function parameters This change has been made to simplify two future changes: 1. Outputting `@`-param assignments after a `super` call. In this case it is necessary that non-`@` parameters are available before `super` is called, so destructuring has to happen before `this` assignment. 2. Compiling destructured assignment to ES6 In this case also destructuring has to happen before `this`, as destructuring can happen in the arguments list, but `this` assignment can not. A bonus side-effect is that default values for `@` params are now output as ES6 default parameters, e.g. (@a = 1) -> becomes function a (a = 1) { this.a = a; } * Change `super` handling in class constructors Inside an ES derived constructor (a constructor for a class that extends another class), it is impossible to access `this` until `super` has been called. This conflicts with CoffeeScript's `@`-param and bound method features, which compile to `this` references at the top of a function body. For example: class B extends A constructor: (@param) -> super method: => This would compile to something like: class B extends A { constructor (param) { this.param = param; this.method = bind(this.method, this); super(...arguments); } } This would break in an ES-compliant runtime as there are `this` references before the call to `super`. Before this commit we were dealing with this by injecting an implicit `super` call into derived constructors that do not already have an explicit `super` call. Furthermore, we would disallow explicit `super` calls in derived constructors that used bound methods or `@`-params, meaning the above example would need to be rewritten as: class B extends A constructor: (@param) -> method: => This would result in a call to `super(...arguments)` being generated as the first expression in `B#constructor`. Whilst this approach seems to work pretty well, and is arguably more convenient than having to manually call `super` when you don't particularly care about the arguments, it does introduce some 'magic' and separation from ES, and would likely be a pain point in a project that made use of significant constructor overriding. This commit introduces a mechanism through which `super` in constructors is 'expanded' to include any generated `this` assignments, whilst retaining the same semantics of a super call. The first example above now compiles to something like: class B extends A { constructor (param) { var ref ref = super(...arguments), this.param = param, this.method = bind(this.method, this), ref; } } * Improve `super` handling in constructors Rather than functions expanding their `super` calls, the `SuperCall` node can now be given a list of `thisAssignments` to apply when it is compiled. This allows us to use the normal compiler machinery to determine whether the `super` result needs to be cached, whether it appears inline or not, etc. * Fix anonymous classes at the top level Anonymous classes in ES are only valid within expressions. If an anonymous class is at the top level it will now be wrapped in parenthses to force it into an expression. * Re-add Parens wrapper around executable class bodies This was lost in the refactoring, but it necessary to ensure `new class ...` works as expected when there's an executable body. * Throw compiler errors for badly configured derived constructors Rather than letting them become runtime errors, the following checks are now performed when compiling a derived constructor: - The constructor **must** include a call to `super`. - The constructor **must not** reference `this` in the function body before `super` has been called. * Add some tests exercising new class behaviour - async methods in classes - `this` access after `super` in extended classes - constructor super in arrow functions - constructor functions can't be async - constructor functions can't be generators - derived constructors must call super - derived constructors can't reference `this` before calling super - generator methods in classes - 'new' target * Improve constructor `super` errors Add a check for `super` in non-extended class constructors, and explicitly mention derived constructors in the "can't reference this before super" error. * Fix compilation of multiple `super` paths in derived constructors `super` can only be called once, but it can be called conditionally from multiple locations. The chosen fix is to add the `this` assignments to every super call. * Additional class tests, added as a separate file to simplify testing and merging. Some methods are commented out because they currently throw and I'm not sure how to test for compilation errors like those. There is also one test which I deliberately left without passing, `super` in an external prototype override. This test should 'pass' but is really a variation on the failing `super only allowed in an instance method` tests above it. * Changes to the tests. Found bug in super in prototype method. fixed. * Added failing test back in, dealing with bound functions in external prototype overrides. * Located a bug in the compiler relating to assertions and escaped ES6 classes. * Move tests from classes-additional.coffee into classes.coffee; comment out console.log * Cleaned up tests and made changes based on feedback. Test at the end still has issues, but it's commented out for now. * Make HoistTarget.expand recursive It's possible that a hoisted node may itself contain hoisted nodes (e.g. a class method inside a class method). For this to work the hoisted fragments need to be expanded recursively. * Uncomment final test in classes.coffee The test case now compiles, however another issue is affecting the test due to the error for `this` before `super` triggering based on source order rather than execution order. These have been commented out for now. * Fixed last test TODOs in test/classes.coffee Turns out an expression like `this.foo = super()` won't run in JS as it attempts to lookup `this` before evaluating `super` (i.e. throws "this is not defined"). * Added more tests for compatability checks, statics, prototypes and ES6 expectations. Cleaned test "nested classes with super". * Changes to reflect feedback and to comment out issues that will be addressed seperately. * Clean up test/classes.coffee - Trim trailing whitespace. - Rephrase a condition to be more idiomatic. * Remove check for `super` in derived constructors In order to be usable at runtime, an extended ES class must call `super` OR return an alternative object. This check prevented the latter case, and checking for an alternative return can't be completed statically without control flow analysis. * Disallow 'super' in constructor parameter defaults There are many edge cases when combining 'super' in parameter defaults with @-parameters and bound functions (and potentially property initializers in the future). Rather than attempting to resolve these edge cases, 'super' is now explicitly disallowed in constructor parameter defaults. * Disallow @-params in derived constructors without 'super' @-parameters can't be assigned unless 'super' is called.
2017-01-13 00:55:30 -05:00
test "@ params super race condition", ->
classA = """
class A
constructor: (@drink) ->
make: -> "Making a #{@drink}"
"""
throwsB = """
class B extends A
constructor: (@params) ->
b = new B('Machiato')
"""
throwsCompileError classA + throwsB, bare: yes
[CS2] Compile class constructors to ES2015 classes (#4354) * Compile classes to ES2015 classes Rather than compiling classes to named functions with prototype and class assignments, they are now compiled to ES2015 class declarations. Backwards compatibility has been maintained by compiling ES2015- incompatible properties as prototype or class assignments. `super` continues to be compiled as before. Where possible, classes will be compiled "bare", without an enclosing IIFE. This is possible when the class contains only ES2015 compatible expressions (methods and static methods), and has no parent (this last constraint is a result of the legacy `super` compilation, and could be removed once ES2015 `super` is being used). Classes are still assigned to variables to maintain compatibility for assigned class expressions. There are a few changes to existing functionality that could break backwards compatibility: - Derived constructors that deliberately don't call `super` are no longer possible. ES2015 derived classes can't use `this` unless the parent constructor has been called, so it's now called implicitly when not present. - As a consequence of the above, derived constructors with @ parameters or bound methods and explicit `super` calls are not allowed. The implicit `super` must be used in these cases. * Add tests to verify class interoperability with ES * Refactor class nodes to separate executable body logic Logic has been redistributed amongst the class nodes so that: - `Class` contains the logic necessary to compile an ES class declaration. - `ExecutableClassBody` contains the logic necessary to compile CS' class extensions that require an executable class body. `Class` still necessarily contains logic to determine whether an expression is valid in an ES class initializer or not. If any invalid expressions are found then `Class` will wrap itself in an `ExecutableClassBody` when compiling. * Rename `Code#static` to `Code#isStatic` This naming is more consistent with other `Code` flags. * Output anonymous classes when possible Anonymous classes can be output when: - The class has no parent. The current super compilation needs a class variable to reference. This condition will go away when ES2015 super is in use. - The class contains no bound static methods. Bound static methods have their context set to the class name. * Throw errors at compile time for async or generator constructors * Improve handling of anonymous classes Anonymous classes are now always anonymous. If a name is required (e.g. for bound static methods or derived classes) then the class is compiled in an `ExecutableClassBody` which will give the anonymous class a stable reference. * Add a `replaceInContext` method to `Node` `replaceInContext` will traverse children looking for a node for which `match` returns true. Once found, the matching node will be replaced by the result of calling `replacement`. * Separate `this` assignments from function parameters This change has been made to simplify two future changes: 1. Outputting `@`-param assignments after a `super` call. In this case it is necessary that non-`@` parameters are available before `super` is called, so destructuring has to happen before `this` assignment. 2. Compiling destructured assignment to ES6 In this case also destructuring has to happen before `this`, as destructuring can happen in the arguments list, but `this` assignment can not. A bonus side-effect is that default values for `@` params are now output as ES6 default parameters, e.g. (@a = 1) -> becomes function a (a = 1) { this.a = a; } * Change `super` handling in class constructors Inside an ES derived constructor (a constructor for a class that extends another class), it is impossible to access `this` until `super` has been called. This conflicts with CoffeeScript's `@`-param and bound method features, which compile to `this` references at the top of a function body. For example: class B extends A constructor: (@param) -> super method: => This would compile to something like: class B extends A { constructor (param) { this.param = param; this.method = bind(this.method, this); super(...arguments); } } This would break in an ES-compliant runtime as there are `this` references before the call to `super`. Before this commit we were dealing with this by injecting an implicit `super` call into derived constructors that do not already have an explicit `super` call. Furthermore, we would disallow explicit `super` calls in derived constructors that used bound methods or `@`-params, meaning the above example would need to be rewritten as: class B extends A constructor: (@param) -> method: => This would result in a call to `super(...arguments)` being generated as the first expression in `B#constructor`. Whilst this approach seems to work pretty well, and is arguably more convenient than having to manually call `super` when you don't particularly care about the arguments, it does introduce some 'magic' and separation from ES, and would likely be a pain point in a project that made use of significant constructor overriding. This commit introduces a mechanism through which `super` in constructors is 'expanded' to include any generated `this` assignments, whilst retaining the same semantics of a super call. The first example above now compiles to something like: class B extends A { constructor (param) { var ref ref = super(...arguments), this.param = param, this.method = bind(this.method, this), ref; } } * Improve `super` handling in constructors Rather than functions expanding their `super` calls, the `SuperCall` node can now be given a list of `thisAssignments` to apply when it is compiled. This allows us to use the normal compiler machinery to determine whether the `super` result needs to be cached, whether it appears inline or not, etc. * Fix anonymous classes at the top level Anonymous classes in ES are only valid within expressions. If an anonymous class is at the top level it will now be wrapped in parenthses to force it into an expression. * Re-add Parens wrapper around executable class bodies This was lost in the refactoring, but it necessary to ensure `new class ...` works as expected when there's an executable body. * Throw compiler errors for badly configured derived constructors Rather than letting them become runtime errors, the following checks are now performed when compiling a derived constructor: - The constructor **must** include a call to `super`. - The constructor **must not** reference `this` in the function body before `super` has been called. * Add some tests exercising new class behaviour - async methods in classes - `this` access after `super` in extended classes - constructor super in arrow functions - constructor functions can't be async - constructor functions can't be generators - derived constructors must call super - derived constructors can't reference `this` before calling super - generator methods in classes - 'new' target * Improve constructor `super` errors Add a check for `super` in non-extended class constructors, and explicitly mention derived constructors in the "can't reference this before super" error. * Fix compilation of multiple `super` paths in derived constructors `super` can only be called once, but it can be called conditionally from multiple locations. The chosen fix is to add the `this` assignments to every super call. * Additional class tests, added as a separate file to simplify testing and merging. Some methods are commented out because they currently throw and I'm not sure how to test for compilation errors like those. There is also one test which I deliberately left without passing, `super` in an external prototype override. This test should 'pass' but is really a variation on the failing `super only allowed in an instance method` tests above it. * Changes to the tests. Found bug in super in prototype method. fixed. * Added failing test back in, dealing with bound functions in external prototype overrides. * Located a bug in the compiler relating to assertions and escaped ES6 classes. * Move tests from classes-additional.coffee into classes.coffee; comment out console.log * Cleaned up tests and made changes based on feedback. Test at the end still has issues, but it's commented out for now. * Make HoistTarget.expand recursive It's possible that a hoisted node may itself contain hoisted nodes (e.g. a class method inside a class method). For this to work the hoisted fragments need to be expanded recursively. * Uncomment final test in classes.coffee The test case now compiles, however another issue is affecting the test due to the error for `this` before `super` triggering based on source order rather than execution order. These have been commented out for now. * Fixed last test TODOs in test/classes.coffee Turns out an expression like `this.foo = super()` won't run in JS as it attempts to lookup `this` before evaluating `super` (i.e. throws "this is not defined"). * Added more tests for compatability checks, statics, prototypes and ES6 expectations. Cleaned test "nested classes with super". * Changes to reflect feedback and to comment out issues that will be addressed seperately. * Clean up test/classes.coffee - Trim trailing whitespace. - Rephrase a condition to be more idiomatic. * Remove check for `super` in derived constructors In order to be usable at runtime, an extended ES class must call `super` OR return an alternative object. This check prevented the latter case, and checking for an alternative return can't be completed statically without control flow analysis. * Disallow 'super' in constructor parameter defaults There are many edge cases when combining 'super' in parameter defaults with @-parameters and bound functions (and potentially property initializers in the future). Rather than attempting to resolve these edge cases, 'super' is now explicitly disallowed in constructor parameter defaults. * Disallow @-params in derived constructors without 'super' @-parameters can't be assigned unless 'super' is called.
2017-01-13 00:55:30 -05:00
# Race condition with @ and super
throwsC = """
class C extends A
constructor: (@params) ->
super(@params)
c = new C('Machiato')
"""
throwsCompileError classA + throwsC, bare: yes
[CS2] Compile class constructors to ES2015 classes (#4354) * Compile classes to ES2015 classes Rather than compiling classes to named functions with prototype and class assignments, they are now compiled to ES2015 class declarations. Backwards compatibility has been maintained by compiling ES2015- incompatible properties as prototype or class assignments. `super` continues to be compiled as before. Where possible, classes will be compiled "bare", without an enclosing IIFE. This is possible when the class contains only ES2015 compatible expressions (methods and static methods), and has no parent (this last constraint is a result of the legacy `super` compilation, and could be removed once ES2015 `super` is being used). Classes are still assigned to variables to maintain compatibility for assigned class expressions. There are a few changes to existing functionality that could break backwards compatibility: - Derived constructors that deliberately don't call `super` are no longer possible. ES2015 derived classes can't use `this` unless the parent constructor has been called, so it's now called implicitly when not present. - As a consequence of the above, derived constructors with @ parameters or bound methods and explicit `super` calls are not allowed. The implicit `super` must be used in these cases. * Add tests to verify class interoperability with ES * Refactor class nodes to separate executable body logic Logic has been redistributed amongst the class nodes so that: - `Class` contains the logic necessary to compile an ES class declaration. - `ExecutableClassBody` contains the logic necessary to compile CS' class extensions that require an executable class body. `Class` still necessarily contains logic to determine whether an expression is valid in an ES class initializer or not. If any invalid expressions are found then `Class` will wrap itself in an `ExecutableClassBody` when compiling. * Rename `Code#static` to `Code#isStatic` This naming is more consistent with other `Code` flags. * Output anonymous classes when possible Anonymous classes can be output when: - The class has no parent. The current super compilation needs a class variable to reference. This condition will go away when ES2015 super is in use. - The class contains no bound static methods. Bound static methods have their context set to the class name. * Throw errors at compile time for async or generator constructors * Improve handling of anonymous classes Anonymous classes are now always anonymous. If a name is required (e.g. for bound static methods or derived classes) then the class is compiled in an `ExecutableClassBody` which will give the anonymous class a stable reference. * Add a `replaceInContext` method to `Node` `replaceInContext` will traverse children looking for a node for which `match` returns true. Once found, the matching node will be replaced by the result of calling `replacement`. * Separate `this` assignments from function parameters This change has been made to simplify two future changes: 1. Outputting `@`-param assignments after a `super` call. In this case it is necessary that non-`@` parameters are available before `super` is called, so destructuring has to happen before `this` assignment. 2. Compiling destructured assignment to ES6 In this case also destructuring has to happen before `this`, as destructuring can happen in the arguments list, but `this` assignment can not. A bonus side-effect is that default values for `@` params are now output as ES6 default parameters, e.g. (@a = 1) -> becomes function a (a = 1) { this.a = a; } * Change `super` handling in class constructors Inside an ES derived constructor (a constructor for a class that extends another class), it is impossible to access `this` until `super` has been called. This conflicts with CoffeeScript's `@`-param and bound method features, which compile to `this` references at the top of a function body. For example: class B extends A constructor: (@param) -> super method: => This would compile to something like: class B extends A { constructor (param) { this.param = param; this.method = bind(this.method, this); super(...arguments); } } This would break in an ES-compliant runtime as there are `this` references before the call to `super`. Before this commit we were dealing with this by injecting an implicit `super` call into derived constructors that do not already have an explicit `super` call. Furthermore, we would disallow explicit `super` calls in derived constructors that used bound methods or `@`-params, meaning the above example would need to be rewritten as: class B extends A constructor: (@param) -> method: => This would result in a call to `super(...arguments)` being generated as the first expression in `B#constructor`. Whilst this approach seems to work pretty well, and is arguably more convenient than having to manually call `super` when you don't particularly care about the arguments, it does introduce some 'magic' and separation from ES, and would likely be a pain point in a project that made use of significant constructor overriding. This commit introduces a mechanism through which `super` in constructors is 'expanded' to include any generated `this` assignments, whilst retaining the same semantics of a super call. The first example above now compiles to something like: class B extends A { constructor (param) { var ref ref = super(...arguments), this.param = param, this.method = bind(this.method, this), ref; } } * Improve `super` handling in constructors Rather than functions expanding their `super` calls, the `SuperCall` node can now be given a list of `thisAssignments` to apply when it is compiled. This allows us to use the normal compiler machinery to determine whether the `super` result needs to be cached, whether it appears inline or not, etc. * Fix anonymous classes at the top level Anonymous classes in ES are only valid within expressions. If an anonymous class is at the top level it will now be wrapped in parenthses to force it into an expression. * Re-add Parens wrapper around executable class bodies This was lost in the refactoring, but it necessary to ensure `new class ...` works as expected when there's an executable body. * Throw compiler errors for badly configured derived constructors Rather than letting them become runtime errors, the following checks are now performed when compiling a derived constructor: - The constructor **must** include a call to `super`. - The constructor **must not** reference `this` in the function body before `super` has been called. * Add some tests exercising new class behaviour - async methods in classes - `this` access after `super` in extended classes - constructor super in arrow functions - constructor functions can't be async - constructor functions can't be generators - derived constructors must call super - derived constructors can't reference `this` before calling super - generator methods in classes - 'new' target * Improve constructor `super` errors Add a check for `super` in non-extended class constructors, and explicitly mention derived constructors in the "can't reference this before super" error. * Fix compilation of multiple `super` paths in derived constructors `super` can only be called once, but it can be called conditionally from multiple locations. The chosen fix is to add the `this` assignments to every super call. * Additional class tests, added as a separate file to simplify testing and merging. Some methods are commented out because they currently throw and I'm not sure how to test for compilation errors like those. There is also one test which I deliberately left without passing, `super` in an external prototype override. This test should 'pass' but is really a variation on the failing `super only allowed in an instance method` tests above it. * Changes to the tests. Found bug in super in prototype method. fixed. * Added failing test back in, dealing with bound functions in external prototype overrides. * Located a bug in the compiler relating to assertions and escaped ES6 classes. * Move tests from classes-additional.coffee into classes.coffee; comment out console.log * Cleaned up tests and made changes based on feedback. Test at the end still has issues, but it's commented out for now. * Make HoistTarget.expand recursive It's possible that a hoisted node may itself contain hoisted nodes (e.g. a class method inside a class method). For this to work the hoisted fragments need to be expanded recursively. * Uncomment final test in classes.coffee The test case now compiles, however another issue is affecting the test due to the error for `this` before `super` triggering based on source order rather than execution order. These have been commented out for now. * Fixed last test TODOs in test/classes.coffee Turns out an expression like `this.foo = super()` won't run in JS as it attempts to lookup `this` before evaluating `super` (i.e. throws "this is not defined"). * Added more tests for compatability checks, statics, prototypes and ES6 expectations. Cleaned test "nested classes with super". * Changes to reflect feedback and to comment out issues that will be addressed seperately. * Clean up test/classes.coffee - Trim trailing whitespace. - Rephrase a condition to be more idiomatic. * Remove check for `super` in derived constructors In order to be usable at runtime, an extended ES class must call `super` OR return an alternative object. This check prevented the latter case, and checking for an alternative return can't be completed statically without control flow analysis. * Disallow 'super' in constructor parameter defaults There are many edge cases when combining 'super' in parameter defaults with @-parameters and bound functions (and potentially property initializers in the future). Rather than attempting to resolve these edge cases, 'super' is now explicitly disallowed in constructor parameter defaults. * Disallow @-params in derived constructors without 'super' @-parameters can't be assigned unless 'super' is called.
2017-01-13 00:55:30 -05:00
test "@ with super call", ->
class D
make: -> "Making a #{@drink}"
class E extends D
constructor: (@drink) ->
super()
e = new E('Machiato')
eq e.make(), "Making a Machiato"
test "@ with splats and super call", ->
class A
make: -> "Making a #{@drink}"
class B extends A
constructor: (@drink...) ->
super()
B = new B('Machiato')
eq B.make(), "Making a Machiato"
test "super and external constructors", ->
# external constructor with @ param is allowed
ctorA = (@drink) ->
class A
constructor: ctorA
make: -> "Making a #{@drink}"
a = new A('Machiato')
eq a.make(), "Making a Machiato"
# External constructor with super
throwsC = """
class B
constructor: (@drink) ->
make: -> "Making a #{@drink}"
ctorC = (drink) ->
super(drink)
class C extends B
constructor: ctorC
c = new C('Machiato')
"""
throwsCompileError throwsC, bare: yes
[CS2] Compile class constructors to ES2015 classes (#4354) * Compile classes to ES2015 classes Rather than compiling classes to named functions with prototype and class assignments, they are now compiled to ES2015 class declarations. Backwards compatibility has been maintained by compiling ES2015- incompatible properties as prototype or class assignments. `super` continues to be compiled as before. Where possible, classes will be compiled "bare", without an enclosing IIFE. This is possible when the class contains only ES2015 compatible expressions (methods and static methods), and has no parent (this last constraint is a result of the legacy `super` compilation, and could be removed once ES2015 `super` is being used). Classes are still assigned to variables to maintain compatibility for assigned class expressions. There are a few changes to existing functionality that could break backwards compatibility: - Derived constructors that deliberately don't call `super` are no longer possible. ES2015 derived classes can't use `this` unless the parent constructor has been called, so it's now called implicitly when not present. - As a consequence of the above, derived constructors with @ parameters or bound methods and explicit `super` calls are not allowed. The implicit `super` must be used in these cases. * Add tests to verify class interoperability with ES * Refactor class nodes to separate executable body logic Logic has been redistributed amongst the class nodes so that: - `Class` contains the logic necessary to compile an ES class declaration. - `ExecutableClassBody` contains the logic necessary to compile CS' class extensions that require an executable class body. `Class` still necessarily contains logic to determine whether an expression is valid in an ES class initializer or not. If any invalid expressions are found then `Class` will wrap itself in an `ExecutableClassBody` when compiling. * Rename `Code#static` to `Code#isStatic` This naming is more consistent with other `Code` flags. * Output anonymous classes when possible Anonymous classes can be output when: - The class has no parent. The current super compilation needs a class variable to reference. This condition will go away when ES2015 super is in use. - The class contains no bound static methods. Bound static methods have their context set to the class name. * Throw errors at compile time for async or generator constructors * Improve handling of anonymous classes Anonymous classes are now always anonymous. If a name is required (e.g. for bound static methods or derived classes) then the class is compiled in an `ExecutableClassBody` which will give the anonymous class a stable reference. * Add a `replaceInContext` method to `Node` `replaceInContext` will traverse children looking for a node for which `match` returns true. Once found, the matching node will be replaced by the result of calling `replacement`. * Separate `this` assignments from function parameters This change has been made to simplify two future changes: 1. Outputting `@`-param assignments after a `super` call. In this case it is necessary that non-`@` parameters are available before `super` is called, so destructuring has to happen before `this` assignment. 2. Compiling destructured assignment to ES6 In this case also destructuring has to happen before `this`, as destructuring can happen in the arguments list, but `this` assignment can not. A bonus side-effect is that default values for `@` params are now output as ES6 default parameters, e.g. (@a = 1) -> becomes function a (a = 1) { this.a = a; } * Change `super` handling in class constructors Inside an ES derived constructor (a constructor for a class that extends another class), it is impossible to access `this` until `super` has been called. This conflicts with CoffeeScript's `@`-param and bound method features, which compile to `this` references at the top of a function body. For example: class B extends A constructor: (@param) -> super method: => This would compile to something like: class B extends A { constructor (param) { this.param = param; this.method = bind(this.method, this); super(...arguments); } } This would break in an ES-compliant runtime as there are `this` references before the call to `super`. Before this commit we were dealing with this by injecting an implicit `super` call into derived constructors that do not already have an explicit `super` call. Furthermore, we would disallow explicit `super` calls in derived constructors that used bound methods or `@`-params, meaning the above example would need to be rewritten as: class B extends A constructor: (@param) -> method: => This would result in a call to `super(...arguments)` being generated as the first expression in `B#constructor`. Whilst this approach seems to work pretty well, and is arguably more convenient than having to manually call `super` when you don't particularly care about the arguments, it does introduce some 'magic' and separation from ES, and would likely be a pain point in a project that made use of significant constructor overriding. This commit introduces a mechanism through which `super` in constructors is 'expanded' to include any generated `this` assignments, whilst retaining the same semantics of a super call. The first example above now compiles to something like: class B extends A { constructor (param) { var ref ref = super(...arguments), this.param = param, this.method = bind(this.method, this), ref; } } * Improve `super` handling in constructors Rather than functions expanding their `super` calls, the `SuperCall` node can now be given a list of `thisAssignments` to apply when it is compiled. This allows us to use the normal compiler machinery to determine whether the `super` result needs to be cached, whether it appears inline or not, etc. * Fix anonymous classes at the top level Anonymous classes in ES are only valid within expressions. If an anonymous class is at the top level it will now be wrapped in parenthses to force it into an expression. * Re-add Parens wrapper around executable class bodies This was lost in the refactoring, but it necessary to ensure `new class ...` works as expected when there's an executable body. * Throw compiler errors for badly configured derived constructors Rather than letting them become runtime errors, the following checks are now performed when compiling a derived constructor: - The constructor **must** include a call to `super`. - The constructor **must not** reference `this` in the function body before `super` has been called. * Add some tests exercising new class behaviour - async methods in classes - `this` access after `super` in extended classes - constructor super in arrow functions - constructor functions can't be async - constructor functions can't be generators - derived constructors must call super - derived constructors can't reference `this` before calling super - generator methods in classes - 'new' target * Improve constructor `super` errors Add a check for `super` in non-extended class constructors, and explicitly mention derived constructors in the "can't reference this before super" error. * Fix compilation of multiple `super` paths in derived constructors `super` can only be called once, but it can be called conditionally from multiple locations. The chosen fix is to add the `this` assignments to every super call. * Additional class tests, added as a separate file to simplify testing and merging. Some methods are commented out because they currently throw and I'm not sure how to test for compilation errors like those. There is also one test which I deliberately left without passing, `super` in an external prototype override. This test should 'pass' but is really a variation on the failing `super only allowed in an instance method` tests above it. * Changes to the tests. Found bug in super in prototype method. fixed. * Added failing test back in, dealing with bound functions in external prototype overrides. * Located a bug in the compiler relating to assertions and escaped ES6 classes. * Move tests from classes-additional.coffee into classes.coffee; comment out console.log * Cleaned up tests and made changes based on feedback. Test at the end still has issues, but it's commented out for now. * Make HoistTarget.expand recursive It's possible that a hoisted node may itself contain hoisted nodes (e.g. a class method inside a class method). For this to work the hoisted fragments need to be expanded recursively. * Uncomment final test in classes.coffee The test case now compiles, however another issue is affecting the test due to the error for `this` before `super` triggering based on source order rather than execution order. These have been commented out for now. * Fixed last test TODOs in test/classes.coffee Turns out an expression like `this.foo = super()` won't run in JS as it attempts to lookup `this` before evaluating `super` (i.e. throws "this is not defined"). * Added more tests for compatability checks, statics, prototypes and ES6 expectations. Cleaned test "nested classes with super". * Changes to reflect feedback and to comment out issues that will be addressed seperately. * Clean up test/classes.coffee - Trim trailing whitespace. - Rephrase a condition to be more idiomatic. * Remove check for `super` in derived constructors In order to be usable at runtime, an extended ES class must call `super` OR return an alternative object. This check prevented the latter case, and checking for an alternative return can't be completed statically without control flow analysis. * Disallow 'super' in constructor parameter defaults There are many edge cases when combining 'super' in parameter defaults with @-parameters and bound functions (and potentially property initializers in the future). Rather than attempting to resolve these edge cases, 'super' is now explicitly disallowed in constructor parameter defaults. * Disallow @-params in derived constructors without 'super' @-parameters can't be assigned unless 'super' is called.
2017-01-13 00:55:30 -05:00
test "bound functions without super", ->
# Bound function with @
# Throw on compile, since bound
# constructors are illegal
throwsA = """
class A
constructor: (drink) =>
@drink = drink
"""
throwsCompileError throwsA, bare: yes
[CS2] Compile class constructors to ES2015 classes (#4354) * Compile classes to ES2015 classes Rather than compiling classes to named functions with prototype and class assignments, they are now compiled to ES2015 class declarations. Backwards compatibility has been maintained by compiling ES2015- incompatible properties as prototype or class assignments. `super` continues to be compiled as before. Where possible, classes will be compiled "bare", without an enclosing IIFE. This is possible when the class contains only ES2015 compatible expressions (methods and static methods), and has no parent (this last constraint is a result of the legacy `super` compilation, and could be removed once ES2015 `super` is being used). Classes are still assigned to variables to maintain compatibility for assigned class expressions. There are a few changes to existing functionality that could break backwards compatibility: - Derived constructors that deliberately don't call `super` are no longer possible. ES2015 derived classes can't use `this` unless the parent constructor has been called, so it's now called implicitly when not present. - As a consequence of the above, derived constructors with @ parameters or bound methods and explicit `super` calls are not allowed. The implicit `super` must be used in these cases. * Add tests to verify class interoperability with ES * Refactor class nodes to separate executable body logic Logic has been redistributed amongst the class nodes so that: - `Class` contains the logic necessary to compile an ES class declaration. - `ExecutableClassBody` contains the logic necessary to compile CS' class extensions that require an executable class body. `Class` still necessarily contains logic to determine whether an expression is valid in an ES class initializer or not. If any invalid expressions are found then `Class` will wrap itself in an `ExecutableClassBody` when compiling. * Rename `Code#static` to `Code#isStatic` This naming is more consistent with other `Code` flags. * Output anonymous classes when possible Anonymous classes can be output when: - The class has no parent. The current super compilation needs a class variable to reference. This condition will go away when ES2015 super is in use. - The class contains no bound static methods. Bound static methods have their context set to the class name. * Throw errors at compile time for async or generator constructors * Improve handling of anonymous classes Anonymous classes are now always anonymous. If a name is required (e.g. for bound static methods or derived classes) then the class is compiled in an `ExecutableClassBody` which will give the anonymous class a stable reference. * Add a `replaceInContext` method to `Node` `replaceInContext` will traverse children looking for a node for which `match` returns true. Once found, the matching node will be replaced by the result of calling `replacement`. * Separate `this` assignments from function parameters This change has been made to simplify two future changes: 1. Outputting `@`-param assignments after a `super` call. In this case it is necessary that non-`@` parameters are available before `super` is called, so destructuring has to happen before `this` assignment. 2. Compiling destructured assignment to ES6 In this case also destructuring has to happen before `this`, as destructuring can happen in the arguments list, but `this` assignment can not. A bonus side-effect is that default values for `@` params are now output as ES6 default parameters, e.g. (@a = 1) -> becomes function a (a = 1) { this.a = a; } * Change `super` handling in class constructors Inside an ES derived constructor (a constructor for a class that extends another class), it is impossible to access `this` until `super` has been called. This conflicts with CoffeeScript's `@`-param and bound method features, which compile to `this` references at the top of a function body. For example: class B extends A constructor: (@param) -> super method: => This would compile to something like: class B extends A { constructor (param) { this.param = param; this.method = bind(this.method, this); super(...arguments); } } This would break in an ES-compliant runtime as there are `this` references before the call to `super`. Before this commit we were dealing with this by injecting an implicit `super` call into derived constructors that do not already have an explicit `super` call. Furthermore, we would disallow explicit `super` calls in derived constructors that used bound methods or `@`-params, meaning the above example would need to be rewritten as: class B extends A constructor: (@param) -> method: => This would result in a call to `super(...arguments)` being generated as the first expression in `B#constructor`. Whilst this approach seems to work pretty well, and is arguably more convenient than having to manually call `super` when you don't particularly care about the arguments, it does introduce some 'magic' and separation from ES, and would likely be a pain point in a project that made use of significant constructor overriding. This commit introduces a mechanism through which `super` in constructors is 'expanded' to include any generated `this` assignments, whilst retaining the same semantics of a super call. The first example above now compiles to something like: class B extends A { constructor (param) { var ref ref = super(...arguments), this.param = param, this.method = bind(this.method, this), ref; } } * Improve `super` handling in constructors Rather than functions expanding their `super` calls, the `SuperCall` node can now be given a list of `thisAssignments` to apply when it is compiled. This allows us to use the normal compiler machinery to determine whether the `super` result needs to be cached, whether it appears inline or not, etc. * Fix anonymous classes at the top level Anonymous classes in ES are only valid within expressions. If an anonymous class is at the top level it will now be wrapped in parenthses to force it into an expression. * Re-add Parens wrapper around executable class bodies This was lost in the refactoring, but it necessary to ensure `new class ...` works as expected when there's an executable body. * Throw compiler errors for badly configured derived constructors Rather than letting them become runtime errors, the following checks are now performed when compiling a derived constructor: - The constructor **must** include a call to `super`. - The constructor **must not** reference `this` in the function body before `super` has been called. * Add some tests exercising new class behaviour - async methods in classes - `this` access after `super` in extended classes - constructor super in arrow functions - constructor functions can't be async - constructor functions can't be generators - derived constructors must call super - derived constructors can't reference `this` before calling super - generator methods in classes - 'new' target * Improve constructor `super` errors Add a check for `super` in non-extended class constructors, and explicitly mention derived constructors in the "can't reference this before super" error. * Fix compilation of multiple `super` paths in derived constructors `super` can only be called once, but it can be called conditionally from multiple locations. The chosen fix is to add the `this` assignments to every super call. * Additional class tests, added as a separate file to simplify testing and merging. Some methods are commented out because they currently throw and I'm not sure how to test for compilation errors like those. There is also one test which I deliberately left without passing, `super` in an external prototype override. This test should 'pass' but is really a variation on the failing `super only allowed in an instance method` tests above it. * Changes to the tests. Found bug in super in prototype method. fixed. * Added failing test back in, dealing with bound functions in external prototype overrides. * Located a bug in the compiler relating to assertions and escaped ES6 classes. * Move tests from classes-additional.coffee into classes.coffee; comment out console.log * Cleaned up tests and made changes based on feedback. Test at the end still has issues, but it's commented out for now. * Make HoistTarget.expand recursive It's possible that a hoisted node may itself contain hoisted nodes (e.g. a class method inside a class method). For this to work the hoisted fragments need to be expanded recursively. * Uncomment final test in classes.coffee The test case now compiles, however another issue is affecting the test due to the error for `this` before `super` triggering based on source order rather than execution order. These have been commented out for now. * Fixed last test TODOs in test/classes.coffee Turns out an expression like `this.foo = super()` won't run in JS as it attempts to lookup `this` before evaluating `super` (i.e. throws "this is not defined"). * Added more tests for compatability checks, statics, prototypes and ES6 expectations. Cleaned test "nested classes with super". * Changes to reflect feedback and to comment out issues that will be addressed seperately. * Clean up test/classes.coffee - Trim trailing whitespace. - Rephrase a condition to be more idiomatic. * Remove check for `super` in derived constructors In order to be usable at runtime, an extended ES class must call `super` OR return an alternative object. This check prevented the latter case, and checking for an alternative return can't be completed statically without control flow analysis. * Disallow 'super' in constructor parameter defaults There are many edge cases when combining 'super' in parameter defaults with @-parameters and bound functions (and potentially property initializers in the future). Rather than attempting to resolve these edge cases, 'super' is now explicitly disallowed in constructor parameter defaults. * Disallow @-params in derived constructors without 'super' @-parameters can't be assigned unless 'super' is called.
2017-01-13 00:55:30 -05:00
test "super in a bound function in a constructor", ->
throwsB = """
class A
class B extends A
constructor: do => super
"""
throwsCompileError throwsB, bare: yes
[CS2] Compile class constructors to ES2015 classes (#4354) * Compile classes to ES2015 classes Rather than compiling classes to named functions with prototype and class assignments, they are now compiled to ES2015 class declarations. Backwards compatibility has been maintained by compiling ES2015- incompatible properties as prototype or class assignments. `super` continues to be compiled as before. Where possible, classes will be compiled "bare", without an enclosing IIFE. This is possible when the class contains only ES2015 compatible expressions (methods and static methods), and has no parent (this last constraint is a result of the legacy `super` compilation, and could be removed once ES2015 `super` is being used). Classes are still assigned to variables to maintain compatibility for assigned class expressions. There are a few changes to existing functionality that could break backwards compatibility: - Derived constructors that deliberately don't call `super` are no longer possible. ES2015 derived classes can't use `this` unless the parent constructor has been called, so it's now called implicitly when not present. - As a consequence of the above, derived constructors with @ parameters or bound methods and explicit `super` calls are not allowed. The implicit `super` must be used in these cases. * Add tests to verify class interoperability with ES * Refactor class nodes to separate executable body logic Logic has been redistributed amongst the class nodes so that: - `Class` contains the logic necessary to compile an ES class declaration. - `ExecutableClassBody` contains the logic necessary to compile CS' class extensions that require an executable class body. `Class` still necessarily contains logic to determine whether an expression is valid in an ES class initializer or not. If any invalid expressions are found then `Class` will wrap itself in an `ExecutableClassBody` when compiling. * Rename `Code#static` to `Code#isStatic` This naming is more consistent with other `Code` flags. * Output anonymous classes when possible Anonymous classes can be output when: - The class has no parent. The current super compilation needs a class variable to reference. This condition will go away when ES2015 super is in use. - The class contains no bound static methods. Bound static methods have their context set to the class name. * Throw errors at compile time for async or generator constructors * Improve handling of anonymous classes Anonymous classes are now always anonymous. If a name is required (e.g. for bound static methods or derived classes) then the class is compiled in an `ExecutableClassBody` which will give the anonymous class a stable reference. * Add a `replaceInContext` method to `Node` `replaceInContext` will traverse children looking for a node for which `match` returns true. Once found, the matching node will be replaced by the result of calling `replacement`. * Separate `this` assignments from function parameters This change has been made to simplify two future changes: 1. Outputting `@`-param assignments after a `super` call. In this case it is necessary that non-`@` parameters are available before `super` is called, so destructuring has to happen before `this` assignment. 2. Compiling destructured assignment to ES6 In this case also destructuring has to happen before `this`, as destructuring can happen in the arguments list, but `this` assignment can not. A bonus side-effect is that default values for `@` params are now output as ES6 default parameters, e.g. (@a = 1) -> becomes function a (a = 1) { this.a = a; } * Change `super` handling in class constructors Inside an ES derived constructor (a constructor for a class that extends another class), it is impossible to access `this` until `super` has been called. This conflicts with CoffeeScript's `@`-param and bound method features, which compile to `this` references at the top of a function body. For example: class B extends A constructor: (@param) -> super method: => This would compile to something like: class B extends A { constructor (param) { this.param = param; this.method = bind(this.method, this); super(...arguments); } } This would break in an ES-compliant runtime as there are `this` references before the call to `super`. Before this commit we were dealing with this by injecting an implicit `super` call into derived constructors that do not already have an explicit `super` call. Furthermore, we would disallow explicit `super` calls in derived constructors that used bound methods or `@`-params, meaning the above example would need to be rewritten as: class B extends A constructor: (@param) -> method: => This would result in a call to `super(...arguments)` being generated as the first expression in `B#constructor`. Whilst this approach seems to work pretty well, and is arguably more convenient than having to manually call `super` when you don't particularly care about the arguments, it does introduce some 'magic' and separation from ES, and would likely be a pain point in a project that made use of significant constructor overriding. This commit introduces a mechanism through which `super` in constructors is 'expanded' to include any generated `this` assignments, whilst retaining the same semantics of a super call. The first example above now compiles to something like: class B extends A { constructor (param) { var ref ref = super(...arguments), this.param = param, this.method = bind(this.method, this), ref; } } * Improve `super` handling in constructors Rather than functions expanding their `super` calls, the `SuperCall` node can now be given a list of `thisAssignments` to apply when it is compiled. This allows us to use the normal compiler machinery to determine whether the `super` result needs to be cached, whether it appears inline or not, etc. * Fix anonymous classes at the top level Anonymous classes in ES are only valid within expressions. If an anonymous class is at the top level it will now be wrapped in parenthses to force it into an expression. * Re-add Parens wrapper around executable class bodies This was lost in the refactoring, but it necessary to ensure `new class ...` works as expected when there's an executable body. * Throw compiler errors for badly configured derived constructors Rather than letting them become runtime errors, the following checks are now performed when compiling a derived constructor: - The constructor **must** include a call to `super`. - The constructor **must not** reference `this` in the function body before `super` has been called. * Add some tests exercising new class behaviour - async methods in classes - `this` access after `super` in extended classes - constructor super in arrow functions - constructor functions can't be async - constructor functions can't be generators - derived constructors must call super - derived constructors can't reference `this` before calling super - generator methods in classes - 'new' target * Improve constructor `super` errors Add a check for `super` in non-extended class constructors, and explicitly mention derived constructors in the "can't reference this before super" error. * Fix compilation of multiple `super` paths in derived constructors `super` can only be called once, but it can be called conditionally from multiple locations. The chosen fix is to add the `this` assignments to every super call. * Additional class tests, added as a separate file to simplify testing and merging. Some methods are commented out because they currently throw and I'm not sure how to test for compilation errors like those. There is also one test which I deliberately left without passing, `super` in an external prototype override. This test should 'pass' but is really a variation on the failing `super only allowed in an instance method` tests above it. * Changes to the tests. Found bug in super in prototype method. fixed. * Added failing test back in, dealing with bound functions in external prototype overrides. * Located a bug in the compiler relating to assertions and escaped ES6 classes. * Move tests from classes-additional.coffee into classes.coffee; comment out console.log * Cleaned up tests and made changes based on feedback. Test at the end still has issues, but it's commented out for now. * Make HoistTarget.expand recursive It's possible that a hoisted node may itself contain hoisted nodes (e.g. a class method inside a class method). For this to work the hoisted fragments need to be expanded recursively. * Uncomment final test in classes.coffee The test case now compiles, however another issue is affecting the test due to the error for `this` before `super` triggering based on source order rather than execution order. These have been commented out for now. * Fixed last test TODOs in test/classes.coffee Turns out an expression like `this.foo = super()` won't run in JS as it attempts to lookup `this` before evaluating `super` (i.e. throws "this is not defined"). * Added more tests for compatability checks, statics, prototypes and ES6 expectations. Cleaned test "nested classes with super". * Changes to reflect feedback and to comment out issues that will be addressed seperately. * Clean up test/classes.coffee - Trim trailing whitespace. - Rephrase a condition to be more idiomatic. * Remove check for `super` in derived constructors In order to be usable at runtime, an extended ES class must call `super` OR return an alternative object. This check prevented the latter case, and checking for an alternative return can't be completed statically without control flow analysis. * Disallow 'super' in constructor parameter defaults There are many edge cases when combining 'super' in parameter defaults with @-parameters and bound functions (and potentially property initializers in the future). Rather than attempting to resolve these edge cases, 'super' is now explicitly disallowed in constructor parameter defaults. * Disallow @-params in derived constructors without 'super' @-parameters can't be assigned unless 'super' is called.
2017-01-13 00:55:30 -05:00
test "super in a bound function", ->
class A
constructor: (@drink) ->
make: -> "Making a #{@drink}"
class B extends A
make: (@flavor) =>
[CS2] Compile all super calls to ES2015 super (#4424) * Compile all super calls to ES2015 super This breaks using `super` in non-methods, meaning several tests are failing. Self-compilation still works. * Use bound functions for IIFEs containing `super` `super` can only be called directly in a method, or in an arrow function. * Fix handling of `class @A extends A` This behaviour worked 'for free' when the parent reference was being cached by the executable class body wrapper. There now needs to be special handling in place to check if the parent name matches the class name, and if so to cache the parent reference. * Fix tests broken by compiling ES2015 `super` * Disallow bare super This removes syntax support for 'bare' super calls, e.g.: class B extends A constructor: -> super `super` must now always be followed with arguments like a regular function call. This also removes the capability of implicitly forwarding arguments. The above can be equivalently be written as: class B extends A constructor: -> super arguments... * Support super with accessors `super` with following accessor(s) is now compiled to ES2015 equivalents. In particular, expressions such as `super.name`, `super[name]`, and also `super.name.prop` are all now valid, and can be used as expected as calls (i.e. `super.name()`) or in expressions (i.e. `if super.name? ...`). `super` without accessors is compiled to a constructor super call in a constructor, and otherwise, as before, to a super call to the method of the same name, i.e. speak: -> super() ...is equivalent to speak: -> super.speak() A neat side-effect of the changes is that existential calls now work properly with super, meaning `super?()` will only call if the super property exists (and is a function). This is not valid for super in constructors. * Prevent calling `super` methods with `new` This fixes a bug in the previous super handling whereby using the `new` operator with a `super` call would silently drop the `new`. This is now an explicit compiler error, as it is invalid JS at runtime. * Clean up some old super handling code This was mostly code for tracking the source classes and variables for methods, which were needed to build the old lookups on `__super__`. * Add TODO to improve bare super parse error * Add some TODOs to improve some of the class tests
2017-02-04 15:03:17 -05:00
super() + " with #{@flavor}"
[CS2] Compile class constructors to ES2015 classes (#4354) * Compile classes to ES2015 classes Rather than compiling classes to named functions with prototype and class assignments, they are now compiled to ES2015 class declarations. Backwards compatibility has been maintained by compiling ES2015- incompatible properties as prototype or class assignments. `super` continues to be compiled as before. Where possible, classes will be compiled "bare", without an enclosing IIFE. This is possible when the class contains only ES2015 compatible expressions (methods and static methods), and has no parent (this last constraint is a result of the legacy `super` compilation, and could be removed once ES2015 `super` is being used). Classes are still assigned to variables to maintain compatibility for assigned class expressions. There are a few changes to existing functionality that could break backwards compatibility: - Derived constructors that deliberately don't call `super` are no longer possible. ES2015 derived classes can't use `this` unless the parent constructor has been called, so it's now called implicitly when not present. - As a consequence of the above, derived constructors with @ parameters or bound methods and explicit `super` calls are not allowed. The implicit `super` must be used in these cases. * Add tests to verify class interoperability with ES * Refactor class nodes to separate executable body logic Logic has been redistributed amongst the class nodes so that: - `Class` contains the logic necessary to compile an ES class declaration. - `ExecutableClassBody` contains the logic necessary to compile CS' class extensions that require an executable class body. `Class` still necessarily contains logic to determine whether an expression is valid in an ES class initializer or not. If any invalid expressions are found then `Class` will wrap itself in an `ExecutableClassBody` when compiling. * Rename `Code#static` to `Code#isStatic` This naming is more consistent with other `Code` flags. * Output anonymous classes when possible Anonymous classes can be output when: - The class has no parent. The current super compilation needs a class variable to reference. This condition will go away when ES2015 super is in use. - The class contains no bound static methods. Bound static methods have their context set to the class name. * Throw errors at compile time for async or generator constructors * Improve handling of anonymous classes Anonymous classes are now always anonymous. If a name is required (e.g. for bound static methods or derived classes) then the class is compiled in an `ExecutableClassBody` which will give the anonymous class a stable reference. * Add a `replaceInContext` method to `Node` `replaceInContext` will traverse children looking for a node for which `match` returns true. Once found, the matching node will be replaced by the result of calling `replacement`. * Separate `this` assignments from function parameters This change has been made to simplify two future changes: 1. Outputting `@`-param assignments after a `super` call. In this case it is necessary that non-`@` parameters are available before `super` is called, so destructuring has to happen before `this` assignment. 2. Compiling destructured assignment to ES6 In this case also destructuring has to happen before `this`, as destructuring can happen in the arguments list, but `this` assignment can not. A bonus side-effect is that default values for `@` params are now output as ES6 default parameters, e.g. (@a = 1) -> becomes function a (a = 1) { this.a = a; } * Change `super` handling in class constructors Inside an ES derived constructor (a constructor for a class that extends another class), it is impossible to access `this` until `super` has been called. This conflicts with CoffeeScript's `@`-param and bound method features, which compile to `this` references at the top of a function body. For example: class B extends A constructor: (@param) -> super method: => This would compile to something like: class B extends A { constructor (param) { this.param = param; this.method = bind(this.method, this); super(...arguments); } } This would break in an ES-compliant runtime as there are `this` references before the call to `super`. Before this commit we were dealing with this by injecting an implicit `super` call into derived constructors that do not already have an explicit `super` call. Furthermore, we would disallow explicit `super` calls in derived constructors that used bound methods or `@`-params, meaning the above example would need to be rewritten as: class B extends A constructor: (@param) -> method: => This would result in a call to `super(...arguments)` being generated as the first expression in `B#constructor`. Whilst this approach seems to work pretty well, and is arguably more convenient than having to manually call `super` when you don't particularly care about the arguments, it does introduce some 'magic' and separation from ES, and would likely be a pain point in a project that made use of significant constructor overriding. This commit introduces a mechanism through which `super` in constructors is 'expanded' to include any generated `this` assignments, whilst retaining the same semantics of a super call. The first example above now compiles to something like: class B extends A { constructor (param) { var ref ref = super(...arguments), this.param = param, this.method = bind(this.method, this), ref; } } * Improve `super` handling in constructors Rather than functions expanding their `super` calls, the `SuperCall` node can now be given a list of `thisAssignments` to apply when it is compiled. This allows us to use the normal compiler machinery to determine whether the `super` result needs to be cached, whether it appears inline or not, etc. * Fix anonymous classes at the top level Anonymous classes in ES are only valid within expressions. If an anonymous class is at the top level it will now be wrapped in parenthses to force it into an expression. * Re-add Parens wrapper around executable class bodies This was lost in the refactoring, but it necessary to ensure `new class ...` works as expected when there's an executable body. * Throw compiler errors for badly configured derived constructors Rather than letting them become runtime errors, the following checks are now performed when compiling a derived constructor: - The constructor **must** include a call to `super`. - The constructor **must not** reference `this` in the function body before `super` has been called. * Add some tests exercising new class behaviour - async methods in classes - `this` access after `super` in extended classes - constructor super in arrow functions - constructor functions can't be async - constructor functions can't be generators - derived constructors must call super - derived constructors can't reference `this` before calling super - generator methods in classes - 'new' target * Improve constructor `super` errors Add a check for `super` in non-extended class constructors, and explicitly mention derived constructors in the "can't reference this before super" error. * Fix compilation of multiple `super` paths in derived constructors `super` can only be called once, but it can be called conditionally from multiple locations. The chosen fix is to add the `this` assignments to every super call. * Additional class tests, added as a separate file to simplify testing and merging. Some methods are commented out because they currently throw and I'm not sure how to test for compilation errors like those. There is also one test which I deliberately left without passing, `super` in an external prototype override. This test should 'pass' but is really a variation on the failing `super only allowed in an instance method` tests above it. * Changes to the tests. Found bug in super in prototype method. fixed. * Added failing test back in, dealing with bound functions in external prototype overrides. * Located a bug in the compiler relating to assertions and escaped ES6 classes. * Move tests from classes-additional.coffee into classes.coffee; comment out console.log * Cleaned up tests and made changes based on feedback. Test at the end still has issues, but it's commented out for now. * Make HoistTarget.expand recursive It's possible that a hoisted node may itself contain hoisted nodes (e.g. a class method inside a class method). For this to work the hoisted fragments need to be expanded recursively. * Uncomment final test in classes.coffee The test case now compiles, however another issue is affecting the test due to the error for `this` before `super` triggering based on source order rather than execution order. These have been commented out for now. * Fixed last test TODOs in test/classes.coffee Turns out an expression like `this.foo = super()` won't run in JS as it attempts to lookup `this` before evaluating `super` (i.e. throws "this is not defined"). * Added more tests for compatability checks, statics, prototypes and ES6 expectations. Cleaned test "nested classes with super". * Changes to reflect feedback and to comment out issues that will be addressed seperately. * Clean up test/classes.coffee - Trim trailing whitespace. - Rephrase a condition to be more idiomatic. * Remove check for `super` in derived constructors In order to be usable at runtime, an extended ES class must call `super` OR return an alternative object. This check prevented the latter case, and checking for an alternative return can't be completed statically without control flow analysis. * Disallow 'super' in constructor parameter defaults There are many edge cases when combining 'super' in parameter defaults with @-parameters and bound functions (and potentially property initializers in the future). Rather than attempting to resolve these edge cases, 'super' is now explicitly disallowed in constructor parameter defaults. * Disallow @-params in derived constructors without 'super' @-parameters can't be assigned unless 'super' is called.
2017-01-13 00:55:30 -05:00
b = new B('Machiato')
eq b.make('vanilla'), "Making a Machiato with vanilla"
# super in a bound function in a bound function
class C extends A
make: (@flavor) =>
[CS2] Compile class constructors to ES2015 classes (#4354) * Compile classes to ES2015 classes Rather than compiling classes to named functions with prototype and class assignments, they are now compiled to ES2015 class declarations. Backwards compatibility has been maintained by compiling ES2015- incompatible properties as prototype or class assignments. `super` continues to be compiled as before. Where possible, classes will be compiled "bare", without an enclosing IIFE. This is possible when the class contains only ES2015 compatible expressions (methods and static methods), and has no parent (this last constraint is a result of the legacy `super` compilation, and could be removed once ES2015 `super` is being used). Classes are still assigned to variables to maintain compatibility for assigned class expressions. There are a few changes to existing functionality that could break backwards compatibility: - Derived constructors that deliberately don't call `super` are no longer possible. ES2015 derived classes can't use `this` unless the parent constructor has been called, so it's now called implicitly when not present. - As a consequence of the above, derived constructors with @ parameters or bound methods and explicit `super` calls are not allowed. The implicit `super` must be used in these cases. * Add tests to verify class interoperability with ES * Refactor class nodes to separate executable body logic Logic has been redistributed amongst the class nodes so that: - `Class` contains the logic necessary to compile an ES class declaration. - `ExecutableClassBody` contains the logic necessary to compile CS' class extensions that require an executable class body. `Class` still necessarily contains logic to determine whether an expression is valid in an ES class initializer or not. If any invalid expressions are found then `Class` will wrap itself in an `ExecutableClassBody` when compiling. * Rename `Code#static` to `Code#isStatic` This naming is more consistent with other `Code` flags. * Output anonymous classes when possible Anonymous classes can be output when: - The class has no parent. The current super compilation needs a class variable to reference. This condition will go away when ES2015 super is in use. - The class contains no bound static methods. Bound static methods have their context set to the class name. * Throw errors at compile time for async or generator constructors * Improve handling of anonymous classes Anonymous classes are now always anonymous. If a name is required (e.g. for bound static methods or derived classes) then the class is compiled in an `ExecutableClassBody` which will give the anonymous class a stable reference. * Add a `replaceInContext` method to `Node` `replaceInContext` will traverse children looking for a node for which `match` returns true. Once found, the matching node will be replaced by the result of calling `replacement`. * Separate `this` assignments from function parameters This change has been made to simplify two future changes: 1. Outputting `@`-param assignments after a `super` call. In this case it is necessary that non-`@` parameters are available before `super` is called, so destructuring has to happen before `this` assignment. 2. Compiling destructured assignment to ES6 In this case also destructuring has to happen before `this`, as destructuring can happen in the arguments list, but `this` assignment can not. A bonus side-effect is that default values for `@` params are now output as ES6 default parameters, e.g. (@a = 1) -> becomes function a (a = 1) { this.a = a; } * Change `super` handling in class constructors Inside an ES derived constructor (a constructor for a class that extends another class), it is impossible to access `this` until `super` has been called. This conflicts with CoffeeScript's `@`-param and bound method features, which compile to `this` references at the top of a function body. For example: class B extends A constructor: (@param) -> super method: => This would compile to something like: class B extends A { constructor (param) { this.param = param; this.method = bind(this.method, this); super(...arguments); } } This would break in an ES-compliant runtime as there are `this` references before the call to `super`. Before this commit we were dealing with this by injecting an implicit `super` call into derived constructors that do not already have an explicit `super` call. Furthermore, we would disallow explicit `super` calls in derived constructors that used bound methods or `@`-params, meaning the above example would need to be rewritten as: class B extends A constructor: (@param) -> method: => This would result in a call to `super(...arguments)` being generated as the first expression in `B#constructor`. Whilst this approach seems to work pretty well, and is arguably more convenient than having to manually call `super` when you don't particularly care about the arguments, it does introduce some 'magic' and separation from ES, and would likely be a pain point in a project that made use of significant constructor overriding. This commit introduces a mechanism through which `super` in constructors is 'expanded' to include any generated `this` assignments, whilst retaining the same semantics of a super call. The first example above now compiles to something like: class B extends A { constructor (param) { var ref ref = super(...arguments), this.param = param, this.method = bind(this.method, this), ref; } } * Improve `super` handling in constructors Rather than functions expanding their `super` calls, the `SuperCall` node can now be given a list of `thisAssignments` to apply when it is compiled. This allows us to use the normal compiler machinery to determine whether the `super` result needs to be cached, whether it appears inline or not, etc. * Fix anonymous classes at the top level Anonymous classes in ES are only valid within expressions. If an anonymous class is at the top level it will now be wrapped in parenthses to force it into an expression. * Re-add Parens wrapper around executable class bodies This was lost in the refactoring, but it necessary to ensure `new class ...` works as expected when there's an executable body. * Throw compiler errors for badly configured derived constructors Rather than letting them become runtime errors, the following checks are now performed when compiling a derived constructor: - The constructor **must** include a call to `super`. - The constructor **must not** reference `this` in the function body before `super` has been called. * Add some tests exercising new class behaviour - async methods in classes - `this` access after `super` in extended classes - constructor super in arrow functions - constructor functions can't be async - constructor functions can't be generators - derived constructors must call super - derived constructors can't reference `this` before calling super - generator methods in classes - 'new' target * Improve constructor `super` errors Add a check for `super` in non-extended class constructors, and explicitly mention derived constructors in the "can't reference this before super" error. * Fix compilation of multiple `super` paths in derived constructors `super` can only be called once, but it can be called conditionally from multiple locations. The chosen fix is to add the `this` assignments to every super call. * Additional class tests, added as a separate file to simplify testing and merging. Some methods are commented out because they currently throw and I'm not sure how to test for compilation errors like those. There is also one test which I deliberately left without passing, `super` in an external prototype override. This test should 'pass' but is really a variation on the failing `super only allowed in an instance method` tests above it. * Changes to the tests. Found bug in super in prototype method. fixed. * Added failing test back in, dealing with bound functions in external prototype overrides. * Located a bug in the compiler relating to assertions and escaped ES6 classes. * Move tests from classes-additional.coffee into classes.coffee; comment out console.log * Cleaned up tests and made changes based on feedback. Test at the end still has issues, but it's commented out for now. * Make HoistTarget.expand recursive It's possible that a hoisted node may itself contain hoisted nodes (e.g. a class method inside a class method). For this to work the hoisted fragments need to be expanded recursively. * Uncomment final test in classes.coffee The test case now compiles, however another issue is affecting the test due to the error for `this` before `super` triggering based on source order rather than execution order. These have been commented out for now. * Fixed last test TODOs in test/classes.coffee Turns out an expression like `this.foo = super()` won't run in JS as it attempts to lookup `this` before evaluating `super` (i.e. throws "this is not defined"). * Added more tests for compatability checks, statics, prototypes and ES6 expectations. Cleaned test "nested classes with super". * Changes to reflect feedback and to comment out issues that will be addressed seperately. * Clean up test/classes.coffee - Trim trailing whitespace. - Rephrase a condition to be more idiomatic. * Remove check for `super` in derived constructors In order to be usable at runtime, an extended ES class must call `super` OR return an alternative object. This check prevented the latter case, and checking for an alternative return can't be completed statically without control flow analysis. * Disallow 'super' in constructor parameter defaults There are many edge cases when combining 'super' in parameter defaults with @-parameters and bound functions (and potentially property initializers in the future). Rather than attempting to resolve these edge cases, 'super' is now explicitly disallowed in constructor parameter defaults. * Disallow @-params in derived constructors without 'super' @-parameters can't be assigned unless 'super' is called.
2017-01-13 00:55:30 -05:00
func = () =>
[CS2] Compile all super calls to ES2015 super (#4424) * Compile all super calls to ES2015 super This breaks using `super` in non-methods, meaning several tests are failing. Self-compilation still works. * Use bound functions for IIFEs containing `super` `super` can only be called directly in a method, or in an arrow function. * Fix handling of `class @A extends A` This behaviour worked 'for free' when the parent reference was being cached by the executable class body wrapper. There now needs to be special handling in place to check if the parent name matches the class name, and if so to cache the parent reference. * Fix tests broken by compiling ES2015 `super` * Disallow bare super This removes syntax support for 'bare' super calls, e.g.: class B extends A constructor: -> super `super` must now always be followed with arguments like a regular function call. This also removes the capability of implicitly forwarding arguments. The above can be equivalently be written as: class B extends A constructor: -> super arguments... * Support super with accessors `super` with following accessor(s) is now compiled to ES2015 equivalents. In particular, expressions such as `super.name`, `super[name]`, and also `super.name.prop` are all now valid, and can be used as expected as calls (i.e. `super.name()`) or in expressions (i.e. `if super.name? ...`). `super` without accessors is compiled to a constructor super call in a constructor, and otherwise, as before, to a super call to the method of the same name, i.e. speak: -> super() ...is equivalent to speak: -> super.speak() A neat side-effect of the changes is that existential calls now work properly with super, meaning `super?()` will only call if the super property exists (and is a function). This is not valid for super in constructors. * Prevent calling `super` methods with `new` This fixes a bug in the previous super handling whereby using the `new` operator with a `super` call would silently drop the `new`. This is now an explicit compiler error, as it is invalid JS at runtime. * Clean up some old super handling code This was mostly code for tracking the source classes and variables for methods, which were needed to build the old lookups on `__super__`. * Add TODO to improve bare super parse error * Add some TODOs to improve some of the class tests
2017-02-04 15:03:17 -05:00
super() + " with #{@flavor}"
[CS2] Compile class constructors to ES2015 classes (#4354) * Compile classes to ES2015 classes Rather than compiling classes to named functions with prototype and class assignments, they are now compiled to ES2015 class declarations. Backwards compatibility has been maintained by compiling ES2015- incompatible properties as prototype or class assignments. `super` continues to be compiled as before. Where possible, classes will be compiled "bare", without an enclosing IIFE. This is possible when the class contains only ES2015 compatible expressions (methods and static methods), and has no parent (this last constraint is a result of the legacy `super` compilation, and could be removed once ES2015 `super` is being used). Classes are still assigned to variables to maintain compatibility for assigned class expressions. There are a few changes to existing functionality that could break backwards compatibility: - Derived constructors that deliberately don't call `super` are no longer possible. ES2015 derived classes can't use `this` unless the parent constructor has been called, so it's now called implicitly when not present. - As a consequence of the above, derived constructors with @ parameters or bound methods and explicit `super` calls are not allowed. The implicit `super` must be used in these cases. * Add tests to verify class interoperability with ES * Refactor class nodes to separate executable body logic Logic has been redistributed amongst the class nodes so that: - `Class` contains the logic necessary to compile an ES class declaration. - `ExecutableClassBody` contains the logic necessary to compile CS' class extensions that require an executable class body. `Class` still necessarily contains logic to determine whether an expression is valid in an ES class initializer or not. If any invalid expressions are found then `Class` will wrap itself in an `ExecutableClassBody` when compiling. * Rename `Code#static` to `Code#isStatic` This naming is more consistent with other `Code` flags. * Output anonymous classes when possible Anonymous classes can be output when: - The class has no parent. The current super compilation needs a class variable to reference. This condition will go away when ES2015 super is in use. - The class contains no bound static methods. Bound static methods have their context set to the class name. * Throw errors at compile time for async or generator constructors * Improve handling of anonymous classes Anonymous classes are now always anonymous. If a name is required (e.g. for bound static methods or derived classes) then the class is compiled in an `ExecutableClassBody` which will give the anonymous class a stable reference. * Add a `replaceInContext` method to `Node` `replaceInContext` will traverse children looking for a node for which `match` returns true. Once found, the matching node will be replaced by the result of calling `replacement`. * Separate `this` assignments from function parameters This change has been made to simplify two future changes: 1. Outputting `@`-param assignments after a `super` call. In this case it is necessary that non-`@` parameters are available before `super` is called, so destructuring has to happen before `this` assignment. 2. Compiling destructured assignment to ES6 In this case also destructuring has to happen before `this`, as destructuring can happen in the arguments list, but `this` assignment can not. A bonus side-effect is that default values for `@` params are now output as ES6 default parameters, e.g. (@a = 1) -> becomes function a (a = 1) { this.a = a; } * Change `super` handling in class constructors Inside an ES derived constructor (a constructor for a class that extends another class), it is impossible to access `this` until `super` has been called. This conflicts with CoffeeScript's `@`-param and bound method features, which compile to `this` references at the top of a function body. For example: class B extends A constructor: (@param) -> super method: => This would compile to something like: class B extends A { constructor (param) { this.param = param; this.method = bind(this.method, this); super(...arguments); } } This would break in an ES-compliant runtime as there are `this` references before the call to `super`. Before this commit we were dealing with this by injecting an implicit `super` call into derived constructors that do not already have an explicit `super` call. Furthermore, we would disallow explicit `super` calls in derived constructors that used bound methods or `@`-params, meaning the above example would need to be rewritten as: class B extends A constructor: (@param) -> method: => This would result in a call to `super(...arguments)` being generated as the first expression in `B#constructor`. Whilst this approach seems to work pretty well, and is arguably more convenient than having to manually call `super` when you don't particularly care about the arguments, it does introduce some 'magic' and separation from ES, and would likely be a pain point in a project that made use of significant constructor overriding. This commit introduces a mechanism through which `super` in constructors is 'expanded' to include any generated `this` assignments, whilst retaining the same semantics of a super call. The first example above now compiles to something like: class B extends A { constructor (param) { var ref ref = super(...arguments), this.param = param, this.method = bind(this.method, this), ref; } } * Improve `super` handling in constructors Rather than functions expanding their `super` calls, the `SuperCall` node can now be given a list of `thisAssignments` to apply when it is compiled. This allows us to use the normal compiler machinery to determine whether the `super` result needs to be cached, whether it appears inline or not, etc. * Fix anonymous classes at the top level Anonymous classes in ES are only valid within expressions. If an anonymous class is at the top level it will now be wrapped in parenthses to force it into an expression. * Re-add Parens wrapper around executable class bodies This was lost in the refactoring, but it necessary to ensure `new class ...` works as expected when there's an executable body. * Throw compiler errors for badly configured derived constructors Rather than letting them become runtime errors, the following checks are now performed when compiling a derived constructor: - The constructor **must** include a call to `super`. - The constructor **must not** reference `this` in the function body before `super` has been called. * Add some tests exercising new class behaviour - async methods in classes - `this` access after `super` in extended classes - constructor super in arrow functions - constructor functions can't be async - constructor functions can't be generators - derived constructors must call super - derived constructors can't reference `this` before calling super - generator methods in classes - 'new' target * Improve constructor `super` errors Add a check for `super` in non-extended class constructors, and explicitly mention derived constructors in the "can't reference this before super" error. * Fix compilation of multiple `super` paths in derived constructors `super` can only be called once, but it can be called conditionally from multiple locations. The chosen fix is to add the `this` assignments to every super call. * Additional class tests, added as a separate file to simplify testing and merging. Some methods are commented out because they currently throw and I'm not sure how to test for compilation errors like those. There is also one test which I deliberately left without passing, `super` in an external prototype override. This test should 'pass' but is really a variation on the failing `super only allowed in an instance method` tests above it. * Changes to the tests. Found bug in super in prototype method. fixed. * Added failing test back in, dealing with bound functions in external prototype overrides. * Located a bug in the compiler relating to assertions and escaped ES6 classes. * Move tests from classes-additional.coffee into classes.coffee; comment out console.log * Cleaned up tests and made changes based on feedback. Test at the end still has issues, but it's commented out for now. * Make HoistTarget.expand recursive It's possible that a hoisted node may itself contain hoisted nodes (e.g. a class method inside a class method). For this to work the hoisted fragments need to be expanded recursively. * Uncomment final test in classes.coffee The test case now compiles, however another issue is affecting the test due to the error for `this` before `super` triggering based on source order rather than execution order. These have been commented out for now. * Fixed last test TODOs in test/classes.coffee Turns out an expression like `this.foo = super()` won't run in JS as it attempts to lookup `this` before evaluating `super` (i.e. throws "this is not defined"). * Added more tests for compatability checks, statics, prototypes and ES6 expectations. Cleaned test "nested classes with super". * Changes to reflect feedback and to comment out issues that will be addressed seperately. * Clean up test/classes.coffee - Trim trailing whitespace. - Rephrase a condition to be more idiomatic. * Remove check for `super` in derived constructors In order to be usable at runtime, an extended ES class must call `super` OR return an alternative object. This check prevented the latter case, and checking for an alternative return can't be completed statically without control flow analysis. * Disallow 'super' in constructor parameter defaults There are many edge cases when combining 'super' in parameter defaults with @-parameters and bound functions (and potentially property initializers in the future). Rather than attempting to resolve these edge cases, 'super' is now explicitly disallowed in constructor parameter defaults. * Disallow @-params in derived constructors without 'super' @-parameters can't be assigned unless 'super' is called.
2017-01-13 00:55:30 -05:00
func()
c = new C('Machiato')
eq c.make('vanilla'), "Making a Machiato with vanilla"
# bound function in a constructor
class D extends A
constructor: (drink) ->
super(drink)
x = =>
eq @drink, "Machiato"
x()
d = new D('Machiato')
eq d.make(), "Making a Machiato"
# duplicate
test "super in a try/catch", ->
classA = """
class A
constructor: (param) ->
throw "" unless param
"""
throwsB = """
class B extends A
constructor: ->
try
[CS2] Compile all super calls to ES2015 super (#4424) * Compile all super calls to ES2015 super This breaks using `super` in non-methods, meaning several tests are failing. Self-compilation still works. * Use bound functions for IIFEs containing `super` `super` can only be called directly in a method, or in an arrow function. * Fix handling of `class @A extends A` This behaviour worked 'for free' when the parent reference was being cached by the executable class body wrapper. There now needs to be special handling in place to check if the parent name matches the class name, and if so to cache the parent reference. * Fix tests broken by compiling ES2015 `super` * Disallow bare super This removes syntax support for 'bare' super calls, e.g.: class B extends A constructor: -> super `super` must now always be followed with arguments like a regular function call. This also removes the capability of implicitly forwarding arguments. The above can be equivalently be written as: class B extends A constructor: -> super arguments... * Support super with accessors `super` with following accessor(s) is now compiled to ES2015 equivalents. In particular, expressions such as `super.name`, `super[name]`, and also `super.name.prop` are all now valid, and can be used as expected as calls (i.e. `super.name()`) or in expressions (i.e. `if super.name? ...`). `super` without accessors is compiled to a constructor super call in a constructor, and otherwise, as before, to a super call to the method of the same name, i.e. speak: -> super() ...is equivalent to speak: -> super.speak() A neat side-effect of the changes is that existential calls now work properly with super, meaning `super?()` will only call if the super property exists (and is a function). This is not valid for super in constructors. * Prevent calling `super` methods with `new` This fixes a bug in the previous super handling whereby using the `new` operator with a `super` call would silently drop the `new`. This is now an explicit compiler error, as it is invalid JS at runtime. * Clean up some old super handling code This was mostly code for tracking the source classes and variables for methods, which were needed to build the old lookups on `__super__`. * Add TODO to improve bare super parse error * Add some TODOs to improve some of the class tests
2017-02-04 15:03:17 -05:00
super()
[CS2] Compile class constructors to ES2015 classes (#4354) * Compile classes to ES2015 classes Rather than compiling classes to named functions with prototype and class assignments, they are now compiled to ES2015 class declarations. Backwards compatibility has been maintained by compiling ES2015- incompatible properties as prototype or class assignments. `super` continues to be compiled as before. Where possible, classes will be compiled "bare", without an enclosing IIFE. This is possible when the class contains only ES2015 compatible expressions (methods and static methods), and has no parent (this last constraint is a result of the legacy `super` compilation, and could be removed once ES2015 `super` is being used). Classes are still assigned to variables to maintain compatibility for assigned class expressions. There are a few changes to existing functionality that could break backwards compatibility: - Derived constructors that deliberately don't call `super` are no longer possible. ES2015 derived classes can't use `this` unless the parent constructor has been called, so it's now called implicitly when not present. - As a consequence of the above, derived constructors with @ parameters or bound methods and explicit `super` calls are not allowed. The implicit `super` must be used in these cases. * Add tests to verify class interoperability with ES * Refactor class nodes to separate executable body logic Logic has been redistributed amongst the class nodes so that: - `Class` contains the logic necessary to compile an ES class declaration. - `ExecutableClassBody` contains the logic necessary to compile CS' class extensions that require an executable class body. `Class` still necessarily contains logic to determine whether an expression is valid in an ES class initializer or not. If any invalid expressions are found then `Class` will wrap itself in an `ExecutableClassBody` when compiling. * Rename `Code#static` to `Code#isStatic` This naming is more consistent with other `Code` flags. * Output anonymous classes when possible Anonymous classes can be output when: - The class has no parent. The current super compilation needs a class variable to reference. This condition will go away when ES2015 super is in use. - The class contains no bound static methods. Bound static methods have their context set to the class name. * Throw errors at compile time for async or generator constructors * Improve handling of anonymous classes Anonymous classes are now always anonymous. If a name is required (e.g. for bound static methods or derived classes) then the class is compiled in an `ExecutableClassBody` which will give the anonymous class a stable reference. * Add a `replaceInContext` method to `Node` `replaceInContext` will traverse children looking for a node for which `match` returns true. Once found, the matching node will be replaced by the result of calling `replacement`. * Separate `this` assignments from function parameters This change has been made to simplify two future changes: 1. Outputting `@`-param assignments after a `super` call. In this case it is necessary that non-`@` parameters are available before `super` is called, so destructuring has to happen before `this` assignment. 2. Compiling destructured assignment to ES6 In this case also destructuring has to happen before `this`, as destructuring can happen in the arguments list, but `this` assignment can not. A bonus side-effect is that default values for `@` params are now output as ES6 default parameters, e.g. (@a = 1) -> becomes function a (a = 1) { this.a = a; } * Change `super` handling in class constructors Inside an ES derived constructor (a constructor for a class that extends another class), it is impossible to access `this` until `super` has been called. This conflicts with CoffeeScript's `@`-param and bound method features, which compile to `this` references at the top of a function body. For example: class B extends A constructor: (@param) -> super method: => This would compile to something like: class B extends A { constructor (param) { this.param = param; this.method = bind(this.method, this); super(...arguments); } } This would break in an ES-compliant runtime as there are `this` references before the call to `super`. Before this commit we were dealing with this by injecting an implicit `super` call into derived constructors that do not already have an explicit `super` call. Furthermore, we would disallow explicit `super` calls in derived constructors that used bound methods or `@`-params, meaning the above example would need to be rewritten as: class B extends A constructor: (@param) -> method: => This would result in a call to `super(...arguments)` being generated as the first expression in `B#constructor`. Whilst this approach seems to work pretty well, and is arguably more convenient than having to manually call `super` when you don't particularly care about the arguments, it does introduce some 'magic' and separation from ES, and would likely be a pain point in a project that made use of significant constructor overriding. This commit introduces a mechanism through which `super` in constructors is 'expanded' to include any generated `this` assignments, whilst retaining the same semantics of a super call. The first example above now compiles to something like: class B extends A { constructor (param) { var ref ref = super(...arguments), this.param = param, this.method = bind(this.method, this), ref; } } * Improve `super` handling in constructors Rather than functions expanding their `super` calls, the `SuperCall` node can now be given a list of `thisAssignments` to apply when it is compiled. This allows us to use the normal compiler machinery to determine whether the `super` result needs to be cached, whether it appears inline or not, etc. * Fix anonymous classes at the top level Anonymous classes in ES are only valid within expressions. If an anonymous class is at the top level it will now be wrapped in parenthses to force it into an expression. * Re-add Parens wrapper around executable class bodies This was lost in the refactoring, but it necessary to ensure `new class ...` works as expected when there's an executable body. * Throw compiler errors for badly configured derived constructors Rather than letting them become runtime errors, the following checks are now performed when compiling a derived constructor: - The constructor **must** include a call to `super`. - The constructor **must not** reference `this` in the function body before `super` has been called. * Add some tests exercising new class behaviour - async methods in classes - `this` access after `super` in extended classes - constructor super in arrow functions - constructor functions can't be async - constructor functions can't be generators - derived constructors must call super - derived constructors can't reference `this` before calling super - generator methods in classes - 'new' target * Improve constructor `super` errors Add a check for `super` in non-extended class constructors, and explicitly mention derived constructors in the "can't reference this before super" error. * Fix compilation of multiple `super` paths in derived constructors `super` can only be called once, but it can be called conditionally from multiple locations. The chosen fix is to add the `this` assignments to every super call. * Additional class tests, added as a separate file to simplify testing and merging. Some methods are commented out because they currently throw and I'm not sure how to test for compilation errors like those. There is also one test which I deliberately left without passing, `super` in an external prototype override. This test should 'pass' but is really a variation on the failing `super only allowed in an instance method` tests above it. * Changes to the tests. Found bug in super in prototype method. fixed. * Added failing test back in, dealing with bound functions in external prototype overrides. * Located a bug in the compiler relating to assertions and escaped ES6 classes. * Move tests from classes-additional.coffee into classes.coffee; comment out console.log * Cleaned up tests and made changes based on feedback. Test at the end still has issues, but it's commented out for now. * Make HoistTarget.expand recursive It's possible that a hoisted node may itself contain hoisted nodes (e.g. a class method inside a class method). For this to work the hoisted fragments need to be expanded recursively. * Uncomment final test in classes.coffee The test case now compiles, however another issue is affecting the test due to the error for `this` before `super` triggering based on source order rather than execution order. These have been commented out for now. * Fixed last test TODOs in test/classes.coffee Turns out an expression like `this.foo = super()` won't run in JS as it attempts to lookup `this` before evaluating `super` (i.e. throws "this is not defined"). * Added more tests for compatability checks, statics, prototypes and ES6 expectations. Cleaned test "nested classes with super". * Changes to reflect feedback and to comment out issues that will be addressed seperately. * Clean up test/classes.coffee - Trim trailing whitespace. - Rephrase a condition to be more idiomatic. * Remove check for `super` in derived constructors In order to be usable at runtime, an extended ES class must call `super` OR return an alternative object. This check prevented the latter case, and checking for an alternative return can't be completed statically without control flow analysis. * Disallow 'super' in constructor parameter defaults There are many edge cases when combining 'super' in parameter defaults with @-parameters and bound functions (and potentially property initializers in the future). Rather than attempting to resolve these edge cases, 'super' is now explicitly disallowed in constructor parameter defaults. * Disallow @-params in derived constructors without 'super' @-parameters can't be assigned unless 'super' is called.
2017-01-13 00:55:30 -05:00
"""
throwsC = """
ctor = ->
try
[CS2] Compile all super calls to ES2015 super (#4424) * Compile all super calls to ES2015 super This breaks using `super` in non-methods, meaning several tests are failing. Self-compilation still works. * Use bound functions for IIFEs containing `super` `super` can only be called directly in a method, or in an arrow function. * Fix handling of `class @A extends A` This behaviour worked 'for free' when the parent reference was being cached by the executable class body wrapper. There now needs to be special handling in place to check if the parent name matches the class name, and if so to cache the parent reference. * Fix tests broken by compiling ES2015 `super` * Disallow bare super This removes syntax support for 'bare' super calls, e.g.: class B extends A constructor: -> super `super` must now always be followed with arguments like a regular function call. This also removes the capability of implicitly forwarding arguments. The above can be equivalently be written as: class B extends A constructor: -> super arguments... * Support super with accessors `super` with following accessor(s) is now compiled to ES2015 equivalents. In particular, expressions such as `super.name`, `super[name]`, and also `super.name.prop` are all now valid, and can be used as expected as calls (i.e. `super.name()`) or in expressions (i.e. `if super.name? ...`). `super` without accessors is compiled to a constructor super call in a constructor, and otherwise, as before, to a super call to the method of the same name, i.e. speak: -> super() ...is equivalent to speak: -> super.speak() A neat side-effect of the changes is that existential calls now work properly with super, meaning `super?()` will only call if the super property exists (and is a function). This is not valid for super in constructors. * Prevent calling `super` methods with `new` This fixes a bug in the previous super handling whereby using the `new` operator with a `super` call would silently drop the `new`. This is now an explicit compiler error, as it is invalid JS at runtime. * Clean up some old super handling code This was mostly code for tracking the source classes and variables for methods, which were needed to build the old lookups on `__super__`. * Add TODO to improve bare super parse error * Add some TODOs to improve some of the class tests
2017-02-04 15:03:17 -05:00
super()
[CS2] Compile class constructors to ES2015 classes (#4354) * Compile classes to ES2015 classes Rather than compiling classes to named functions with prototype and class assignments, they are now compiled to ES2015 class declarations. Backwards compatibility has been maintained by compiling ES2015- incompatible properties as prototype or class assignments. `super` continues to be compiled as before. Where possible, classes will be compiled "bare", without an enclosing IIFE. This is possible when the class contains only ES2015 compatible expressions (methods and static methods), and has no parent (this last constraint is a result of the legacy `super` compilation, and could be removed once ES2015 `super` is being used). Classes are still assigned to variables to maintain compatibility for assigned class expressions. There are a few changes to existing functionality that could break backwards compatibility: - Derived constructors that deliberately don't call `super` are no longer possible. ES2015 derived classes can't use `this` unless the parent constructor has been called, so it's now called implicitly when not present. - As a consequence of the above, derived constructors with @ parameters or bound methods and explicit `super` calls are not allowed. The implicit `super` must be used in these cases. * Add tests to verify class interoperability with ES * Refactor class nodes to separate executable body logic Logic has been redistributed amongst the class nodes so that: - `Class` contains the logic necessary to compile an ES class declaration. - `ExecutableClassBody` contains the logic necessary to compile CS' class extensions that require an executable class body. `Class` still necessarily contains logic to determine whether an expression is valid in an ES class initializer or not. If any invalid expressions are found then `Class` will wrap itself in an `ExecutableClassBody` when compiling. * Rename `Code#static` to `Code#isStatic` This naming is more consistent with other `Code` flags. * Output anonymous classes when possible Anonymous classes can be output when: - The class has no parent. The current super compilation needs a class variable to reference. This condition will go away when ES2015 super is in use. - The class contains no bound static methods. Bound static methods have their context set to the class name. * Throw errors at compile time for async or generator constructors * Improve handling of anonymous classes Anonymous classes are now always anonymous. If a name is required (e.g. for bound static methods or derived classes) then the class is compiled in an `ExecutableClassBody` which will give the anonymous class a stable reference. * Add a `replaceInContext` method to `Node` `replaceInContext` will traverse children looking for a node for which `match` returns true. Once found, the matching node will be replaced by the result of calling `replacement`. * Separate `this` assignments from function parameters This change has been made to simplify two future changes: 1. Outputting `@`-param assignments after a `super` call. In this case it is necessary that non-`@` parameters are available before `super` is called, so destructuring has to happen before `this` assignment. 2. Compiling destructured assignment to ES6 In this case also destructuring has to happen before `this`, as destructuring can happen in the arguments list, but `this` assignment can not. A bonus side-effect is that default values for `@` params are now output as ES6 default parameters, e.g. (@a = 1) -> becomes function a (a = 1) { this.a = a; } * Change `super` handling in class constructors Inside an ES derived constructor (a constructor for a class that extends another class), it is impossible to access `this` until `super` has been called. This conflicts with CoffeeScript's `@`-param and bound method features, which compile to `this` references at the top of a function body. For example: class B extends A constructor: (@param) -> super method: => This would compile to something like: class B extends A { constructor (param) { this.param = param; this.method = bind(this.method, this); super(...arguments); } } This would break in an ES-compliant runtime as there are `this` references before the call to `super`. Before this commit we were dealing with this by injecting an implicit `super` call into derived constructors that do not already have an explicit `super` call. Furthermore, we would disallow explicit `super` calls in derived constructors that used bound methods or `@`-params, meaning the above example would need to be rewritten as: class B extends A constructor: (@param) -> method: => This would result in a call to `super(...arguments)` being generated as the first expression in `B#constructor`. Whilst this approach seems to work pretty well, and is arguably more convenient than having to manually call `super` when you don't particularly care about the arguments, it does introduce some 'magic' and separation from ES, and would likely be a pain point in a project that made use of significant constructor overriding. This commit introduces a mechanism through which `super` in constructors is 'expanded' to include any generated `this` assignments, whilst retaining the same semantics of a super call. The first example above now compiles to something like: class B extends A { constructor (param) { var ref ref = super(...arguments), this.param = param, this.method = bind(this.method, this), ref; } } * Improve `super` handling in constructors Rather than functions expanding their `super` calls, the `SuperCall` node can now be given a list of `thisAssignments` to apply when it is compiled. This allows us to use the normal compiler machinery to determine whether the `super` result needs to be cached, whether it appears inline or not, etc. * Fix anonymous classes at the top level Anonymous classes in ES are only valid within expressions. If an anonymous class is at the top level it will now be wrapped in parenthses to force it into an expression. * Re-add Parens wrapper around executable class bodies This was lost in the refactoring, but it necessary to ensure `new class ...` works as expected when there's an executable body. * Throw compiler errors for badly configured derived constructors Rather than letting them become runtime errors, the following checks are now performed when compiling a derived constructor: - The constructor **must** include a call to `super`. - The constructor **must not** reference `this` in the function body before `super` has been called. * Add some tests exercising new class behaviour - async methods in classes - `this` access after `super` in extended classes - constructor super in arrow functions - constructor functions can't be async - constructor functions can't be generators - derived constructors must call super - derived constructors can't reference `this` before calling super - generator methods in classes - 'new' target * Improve constructor `super` errors Add a check for `super` in non-extended class constructors, and explicitly mention derived constructors in the "can't reference this before super" error. * Fix compilation of multiple `super` paths in derived constructors `super` can only be called once, but it can be called conditionally from multiple locations. The chosen fix is to add the `this` assignments to every super call. * Additional class tests, added as a separate file to simplify testing and merging. Some methods are commented out because they currently throw and I'm not sure how to test for compilation errors like those. There is also one test which I deliberately left without passing, `super` in an external prototype override. This test should 'pass' but is really a variation on the failing `super only allowed in an instance method` tests above it. * Changes to the tests. Found bug in super in prototype method. fixed. * Added failing test back in, dealing with bound functions in external prototype overrides. * Located a bug in the compiler relating to assertions and escaped ES6 classes. * Move tests from classes-additional.coffee into classes.coffee; comment out console.log * Cleaned up tests and made changes based on feedback. Test at the end still has issues, but it's commented out for now. * Make HoistTarget.expand recursive It's possible that a hoisted node may itself contain hoisted nodes (e.g. a class method inside a class method). For this to work the hoisted fragments need to be expanded recursively. * Uncomment final test in classes.coffee The test case now compiles, however another issue is affecting the test due to the error for `this` before `super` triggering based on source order rather than execution order. These have been commented out for now. * Fixed last test TODOs in test/classes.coffee Turns out an expression like `this.foo = super()` won't run in JS as it attempts to lookup `this` before evaluating `super` (i.e. throws "this is not defined"). * Added more tests for compatability checks, statics, prototypes and ES6 expectations. Cleaned test "nested classes with super". * Changes to reflect feedback and to comment out issues that will be addressed seperately. * Clean up test/classes.coffee - Trim trailing whitespace. - Rephrase a condition to be more idiomatic. * Remove check for `super` in derived constructors In order to be usable at runtime, an extended ES class must call `super` OR return an alternative object. This check prevented the latter case, and checking for an alternative return can't be completed statically without control flow analysis. * Disallow 'super' in constructor parameter defaults There are many edge cases when combining 'super' in parameter defaults with @-parameters and bound functions (and potentially property initializers in the future). Rather than attempting to resolve these edge cases, 'super' is now explicitly disallowed in constructor parameter defaults. * Disallow @-params in derived constructors without 'super' @-parameters can't be assigned unless 'super' is called.
2017-01-13 00:55:30 -05:00
class C extends A
constructor: ctor
"""
throws -> CoffeeScript.run classA + throwsB, bare: yes
throws -> CoffeeScript.run classA + throwsC, bare: yes
test "mixed ES6 and CS6 classes with a four-level inheritance chain", ->
# Extended test
# ES2015+ class interoperability
```
class Base {
constructor (greeting) {
this.greeting = greeting || 'hi';
}
func (string) {
return 'zero/' + string;
}
static staticFunc (string) {
return 'static/' + string;
}
}
```
class FirstChild extends Base
func: (string) ->
super('one/') + string
```
class SecondChild extends FirstChild {
func (string) {
return super.func('two/' + string);
}
}
```
thirdCtor = ->
@array = [1, 2, 3]
class ThirdChild extends SecondChild
constructor: ->
super()
thirdCtor.call this
func: (string) ->
super('three/') + string
result = (new ThirdChild).func 'four'
ok result is 'zero/one/two/three/four'
ok Base.staticFunc('word') is 'static/word'
# exercise extends in a nested class
test "nested classes with super", ->
class Outer
constructor: ->
@label = 'outer'
class @Inner
constructor: ->
@label = 'inner'
class @ExtendedInner extends @Inner
constructor: ->
tmp = super()
@label = tmp.label + ' extended'
@extender: () =>
class ExtendedSelf extends @
constructor: ->
tmp = super()
@label = tmp.label + ' from this'
new ExtendedSelf
eq (new Outer).label, 'outer'
eq (new Outer.Inner).label, 'inner'
eq (new Outer.ExtendedInner).label, 'inner extended'
eq (Outer.extender()).label, 'outer from this'
test "Static methods generate 'static' keywords", ->
compile = """
class CheckStatic
constructor: (@drink) ->
@className: -> 'CheckStatic'
c = new CheckStatic('Machiato')
"""
result = CoffeeScript.compile compile, bare: yes
ok result.match(' static ')
test "Static methods in nested classes", ->
class Outer
@name: -> 'Outer'
class @Inner
@name: -> 'Inner'
eq Outer.name(), 'Outer'
eq Outer.Inner.name(), 'Inner'
test "mixed constructors with inheritance and ES6 super", ->
identity = (f) -> f
class TopClass
constructor: (arg) ->
@prop = 'top-' + arg
```
class SuperClass extends TopClass {
constructor (arg) {
identity(super('super-' + arg));
}
}
```
class SubClass extends SuperClass
constructor: ->
identity super 'sub'
ok (new SubClass).prop is 'top-super-sub'
test "ES6 static class methods can be overriden", ->
class A
@name: -> 'A'
class B extends A
@name: -> 'B'
eq A.name(), 'A'
eq B.name(), 'B'
# If creating static by direct assignment rather than ES6 static keyword
test "ES6 Static methods should set `this` to undefined // ES6 ", ->
class A
@test: ->
eq this, undefined
# Ensure that our object prototypes work with ES6
test "ES6 prototypes can be overriden", ->
class A
className: 'classA'
```
class B {
test () {return "B";};
}
```
b = new B
a = new A
eq a.className, 'classA'
eq b.test(), 'B'
Object.setPrototypeOf(b, a)
eq b.className, 'classA'
# This shouldn't throw,
# as we only change inheritance not object construction
# This may be an issue with ES, rather than CS construction?
#eq b.test(), 'B'
class D extends B
B::test = () -> 'D'
eq (new D).test(), 'D'
# TODO: implement this error check
# test "ES6 conformance to extending non-classes", ->
# A = (@title) ->
# 'Title: ' + @
# class B extends A
# b = new B('caffeinated')
# eq b.title, 'caffeinated'
# # Check inheritance chain
# A::getTitle = () -> @title
# eq b.getTitle(), 'caffeinated'
# throwsC = """
# C = {title: 'invalid'}
# class D extends {}
# """
# # This should catch on compile and message should be "class can only extend classes and functions."
# throws -> CoffeeScript.run throwsC, bare: yes
# TODO: Evaluate future compliance with "strict mode";
# test "Class function environment should be in `strict mode`, ie as if 'use strict' was in use", ->
# class A
# # this might be a meaningless test, since these are likely to be runtime errors and different
# # for every browser. Thoughts?
# constructor: () ->
# # Ivalid: prop reassignment
# @state = {prop: [1], prop: {a: 'a'}}
# # eval reassignment
# @badEval = eval;
# # Should throw, but doesn't
# a = new A
test "only one method named constructor allowed", ->
throwsA = """
class A
constructor: (@first) ->
constructor: (@last) ->
"""
throwsCompileError throwsA, bare: yes
[CS2] Compile class constructors to ES2015 classes (#4354) * Compile classes to ES2015 classes Rather than compiling classes to named functions with prototype and class assignments, they are now compiled to ES2015 class declarations. Backwards compatibility has been maintained by compiling ES2015- incompatible properties as prototype or class assignments. `super` continues to be compiled as before. Where possible, classes will be compiled "bare", without an enclosing IIFE. This is possible when the class contains only ES2015 compatible expressions (methods and static methods), and has no parent (this last constraint is a result of the legacy `super` compilation, and could be removed once ES2015 `super` is being used). Classes are still assigned to variables to maintain compatibility for assigned class expressions. There are a few changes to existing functionality that could break backwards compatibility: - Derived constructors that deliberately don't call `super` are no longer possible. ES2015 derived classes can't use `this` unless the parent constructor has been called, so it's now called implicitly when not present. - As a consequence of the above, derived constructors with @ parameters or bound methods and explicit `super` calls are not allowed. The implicit `super` must be used in these cases. * Add tests to verify class interoperability with ES * Refactor class nodes to separate executable body logic Logic has been redistributed amongst the class nodes so that: - `Class` contains the logic necessary to compile an ES class declaration. - `ExecutableClassBody` contains the logic necessary to compile CS' class extensions that require an executable class body. `Class` still necessarily contains logic to determine whether an expression is valid in an ES class initializer or not. If any invalid expressions are found then `Class` will wrap itself in an `ExecutableClassBody` when compiling. * Rename `Code#static` to `Code#isStatic` This naming is more consistent with other `Code` flags. * Output anonymous classes when possible Anonymous classes can be output when: - The class has no parent. The current super compilation needs a class variable to reference. This condition will go away when ES2015 super is in use. - The class contains no bound static methods. Bound static methods have their context set to the class name. * Throw errors at compile time for async or generator constructors * Improve handling of anonymous classes Anonymous classes are now always anonymous. If a name is required (e.g. for bound static methods or derived classes) then the class is compiled in an `ExecutableClassBody` which will give the anonymous class a stable reference. * Add a `replaceInContext` method to `Node` `replaceInContext` will traverse children looking for a node for which `match` returns true. Once found, the matching node will be replaced by the result of calling `replacement`. * Separate `this` assignments from function parameters This change has been made to simplify two future changes: 1. Outputting `@`-param assignments after a `super` call. In this case it is necessary that non-`@` parameters are available before `super` is called, so destructuring has to happen before `this` assignment. 2. Compiling destructured assignment to ES6 In this case also destructuring has to happen before `this`, as destructuring can happen in the arguments list, but `this` assignment can not. A bonus side-effect is that default values for `@` params are now output as ES6 default parameters, e.g. (@a = 1) -> becomes function a (a = 1) { this.a = a; } * Change `super` handling in class constructors Inside an ES derived constructor (a constructor for a class that extends another class), it is impossible to access `this` until `super` has been called. This conflicts with CoffeeScript's `@`-param and bound method features, which compile to `this` references at the top of a function body. For example: class B extends A constructor: (@param) -> super method: => This would compile to something like: class B extends A { constructor (param) { this.param = param; this.method = bind(this.method, this); super(...arguments); } } This would break in an ES-compliant runtime as there are `this` references before the call to `super`. Before this commit we were dealing with this by injecting an implicit `super` call into derived constructors that do not already have an explicit `super` call. Furthermore, we would disallow explicit `super` calls in derived constructors that used bound methods or `@`-params, meaning the above example would need to be rewritten as: class B extends A constructor: (@param) -> method: => This would result in a call to `super(...arguments)` being generated as the first expression in `B#constructor`. Whilst this approach seems to work pretty well, and is arguably more convenient than having to manually call `super` when you don't particularly care about the arguments, it does introduce some 'magic' and separation from ES, and would likely be a pain point in a project that made use of significant constructor overriding. This commit introduces a mechanism through which `super` in constructors is 'expanded' to include any generated `this` assignments, whilst retaining the same semantics of a super call. The first example above now compiles to something like: class B extends A { constructor (param) { var ref ref = super(...arguments), this.param = param, this.method = bind(this.method, this), ref; } } * Improve `super` handling in constructors Rather than functions expanding their `super` calls, the `SuperCall` node can now be given a list of `thisAssignments` to apply when it is compiled. This allows us to use the normal compiler machinery to determine whether the `super` result needs to be cached, whether it appears inline or not, etc. * Fix anonymous classes at the top level Anonymous classes in ES are only valid within expressions. If an anonymous class is at the top level it will now be wrapped in parenthses to force it into an expression. * Re-add Parens wrapper around executable class bodies This was lost in the refactoring, but it necessary to ensure `new class ...` works as expected when there's an executable body. * Throw compiler errors for badly configured derived constructors Rather than letting them become runtime errors, the following checks are now performed when compiling a derived constructor: - The constructor **must** include a call to `super`. - The constructor **must not** reference `this` in the function body before `super` has been called. * Add some tests exercising new class behaviour - async methods in classes - `this` access after `super` in extended classes - constructor super in arrow functions - constructor functions can't be async - constructor functions can't be generators - derived constructors must call super - derived constructors can't reference `this` before calling super - generator methods in classes - 'new' target * Improve constructor `super` errors Add a check for `super` in non-extended class constructors, and explicitly mention derived constructors in the "can't reference this before super" error. * Fix compilation of multiple `super` paths in derived constructors `super` can only be called once, but it can be called conditionally from multiple locations. The chosen fix is to add the `this` assignments to every super call. * Additional class tests, added as a separate file to simplify testing and merging. Some methods are commented out because they currently throw and I'm not sure how to test for compilation errors like those. There is also one test which I deliberately left without passing, `super` in an external prototype override. This test should 'pass' but is really a variation on the failing `super only allowed in an instance method` tests above it. * Changes to the tests. Found bug in super in prototype method. fixed. * Added failing test back in, dealing with bound functions in external prototype overrides. * Located a bug in the compiler relating to assertions and escaped ES6 classes. * Move tests from classes-additional.coffee into classes.coffee; comment out console.log * Cleaned up tests and made changes based on feedback. Test at the end still has issues, but it's commented out for now. * Make HoistTarget.expand recursive It's possible that a hoisted node may itself contain hoisted nodes (e.g. a class method inside a class method). For this to work the hoisted fragments need to be expanded recursively. * Uncomment final test in classes.coffee The test case now compiles, however another issue is affecting the test due to the error for `this` before `super` triggering based on source order rather than execution order. These have been commented out for now. * Fixed last test TODOs in test/classes.coffee Turns out an expression like `this.foo = super()` won't run in JS as it attempts to lookup `this` before evaluating `super` (i.e. throws "this is not defined"). * Added more tests for compatability checks, statics, prototypes and ES6 expectations. Cleaned test "nested classes with super". * Changes to reflect feedback and to comment out issues that will be addressed seperately. * Clean up test/classes.coffee - Trim trailing whitespace. - Rephrase a condition to be more idiomatic. * Remove check for `super` in derived constructors In order to be usable at runtime, an extended ES class must call `super` OR return an alternative object. This check prevented the latter case, and checking for an alternative return can't be completed statically without control flow analysis. * Disallow 'super' in constructor parameter defaults There are many edge cases when combining 'super' in parameter defaults with @-parameters and bound functions (and potentially property initializers in the future). Rather than attempting to resolve these edge cases, 'super' is now explicitly disallowed in constructor parameter defaults. * Disallow @-params in derived constructors without 'super' @-parameters can't be assigned unless 'super' is called.
2017-01-13 00:55:30 -05:00
test "If the constructor of a child class does not call super,it should return an object.", ->
nonce = {}
class A
class B extends A
constructor: ->
return nonce
eq nonce, new B
test "super can only exist in extended classes", ->
throwsA = """
class A
constructor: (@name) ->
super()
"""
throwsCompileError throwsA, bare: yes
[CS2] Compile class constructors to ES2015 classes (#4354) * Compile classes to ES2015 classes Rather than compiling classes to named functions with prototype and class assignments, they are now compiled to ES2015 class declarations. Backwards compatibility has been maintained by compiling ES2015- incompatible properties as prototype or class assignments. `super` continues to be compiled as before. Where possible, classes will be compiled "bare", without an enclosing IIFE. This is possible when the class contains only ES2015 compatible expressions (methods and static methods), and has no parent (this last constraint is a result of the legacy `super` compilation, and could be removed once ES2015 `super` is being used). Classes are still assigned to variables to maintain compatibility for assigned class expressions. There are a few changes to existing functionality that could break backwards compatibility: - Derived constructors that deliberately don't call `super` are no longer possible. ES2015 derived classes can't use `this` unless the parent constructor has been called, so it's now called implicitly when not present. - As a consequence of the above, derived constructors with @ parameters or bound methods and explicit `super` calls are not allowed. The implicit `super` must be used in these cases. * Add tests to verify class interoperability with ES * Refactor class nodes to separate executable body logic Logic has been redistributed amongst the class nodes so that: - `Class` contains the logic necessary to compile an ES class declaration. - `ExecutableClassBody` contains the logic necessary to compile CS' class extensions that require an executable class body. `Class` still necessarily contains logic to determine whether an expression is valid in an ES class initializer or not. If any invalid expressions are found then `Class` will wrap itself in an `ExecutableClassBody` when compiling. * Rename `Code#static` to `Code#isStatic` This naming is more consistent with other `Code` flags. * Output anonymous classes when possible Anonymous classes can be output when: - The class has no parent. The current super compilation needs a class variable to reference. This condition will go away when ES2015 super is in use. - The class contains no bound static methods. Bound static methods have their context set to the class name. * Throw errors at compile time for async or generator constructors * Improve handling of anonymous classes Anonymous classes are now always anonymous. If a name is required (e.g. for bound static methods or derived classes) then the class is compiled in an `ExecutableClassBody` which will give the anonymous class a stable reference. * Add a `replaceInContext` method to `Node` `replaceInContext` will traverse children looking for a node for which `match` returns true. Once found, the matching node will be replaced by the result of calling `replacement`. * Separate `this` assignments from function parameters This change has been made to simplify two future changes: 1. Outputting `@`-param assignments after a `super` call. In this case it is necessary that non-`@` parameters are available before `super` is called, so destructuring has to happen before `this` assignment. 2. Compiling destructured assignment to ES6 In this case also destructuring has to happen before `this`, as destructuring can happen in the arguments list, but `this` assignment can not. A bonus side-effect is that default values for `@` params are now output as ES6 default parameters, e.g. (@a = 1) -> becomes function a (a = 1) { this.a = a; } * Change `super` handling in class constructors Inside an ES derived constructor (a constructor for a class that extends another class), it is impossible to access `this` until `super` has been called. This conflicts with CoffeeScript's `@`-param and bound method features, which compile to `this` references at the top of a function body. For example: class B extends A constructor: (@param) -> super method: => This would compile to something like: class B extends A { constructor (param) { this.param = param; this.method = bind(this.method, this); super(...arguments); } } This would break in an ES-compliant runtime as there are `this` references before the call to `super`. Before this commit we were dealing with this by injecting an implicit `super` call into derived constructors that do not already have an explicit `super` call. Furthermore, we would disallow explicit `super` calls in derived constructors that used bound methods or `@`-params, meaning the above example would need to be rewritten as: class B extends A constructor: (@param) -> method: => This would result in a call to `super(...arguments)` being generated as the first expression in `B#constructor`. Whilst this approach seems to work pretty well, and is arguably more convenient than having to manually call `super` when you don't particularly care about the arguments, it does introduce some 'magic' and separation from ES, and would likely be a pain point in a project that made use of significant constructor overriding. This commit introduces a mechanism through which `super` in constructors is 'expanded' to include any generated `this` assignments, whilst retaining the same semantics of a super call. The first example above now compiles to something like: class B extends A { constructor (param) { var ref ref = super(...arguments), this.param = param, this.method = bind(this.method, this), ref; } } * Improve `super` handling in constructors Rather than functions expanding their `super` calls, the `SuperCall` node can now be given a list of `thisAssignments` to apply when it is compiled. This allows us to use the normal compiler machinery to determine whether the `super` result needs to be cached, whether it appears inline or not, etc. * Fix anonymous classes at the top level Anonymous classes in ES are only valid within expressions. If an anonymous class is at the top level it will now be wrapped in parenthses to force it into an expression. * Re-add Parens wrapper around executable class bodies This was lost in the refactoring, but it necessary to ensure `new class ...` works as expected when there's an executable body. * Throw compiler errors for badly configured derived constructors Rather than letting them become runtime errors, the following checks are now performed when compiling a derived constructor: - The constructor **must** include a call to `super`. - The constructor **must not** reference `this` in the function body before `super` has been called. * Add some tests exercising new class behaviour - async methods in classes - `this` access after `super` in extended classes - constructor super in arrow functions - constructor functions can't be async - constructor functions can't be generators - derived constructors must call super - derived constructors can't reference `this` before calling super - generator methods in classes - 'new' target * Improve constructor `super` errors Add a check for `super` in non-extended class constructors, and explicitly mention derived constructors in the "can't reference this before super" error. * Fix compilation of multiple `super` paths in derived constructors `super` can only be called once, but it can be called conditionally from multiple locations. The chosen fix is to add the `this` assignments to every super call. * Additional class tests, added as a separate file to simplify testing and merging. Some methods are commented out because they currently throw and I'm not sure how to test for compilation errors like those. There is also one test which I deliberately left without passing, `super` in an external prototype override. This test should 'pass' but is really a variation on the failing `super only allowed in an instance method` tests above it. * Changes to the tests. Found bug in super in prototype method. fixed. * Added failing test back in, dealing with bound functions in external prototype overrides. * Located a bug in the compiler relating to assertions and escaped ES6 classes. * Move tests from classes-additional.coffee into classes.coffee; comment out console.log * Cleaned up tests and made changes based on feedback. Test at the end still has issues, but it's commented out for now. * Make HoistTarget.expand recursive It's possible that a hoisted node may itself contain hoisted nodes (e.g. a class method inside a class method). For this to work the hoisted fragments need to be expanded recursively. * Uncomment final test in classes.coffee The test case now compiles, however another issue is affecting the test due to the error for `this` before `super` triggering based on source order rather than execution order. These have been commented out for now. * Fixed last test TODOs in test/classes.coffee Turns out an expression like `this.foo = super()` won't run in JS as it attempts to lookup `this` before evaluating `super` (i.e. throws "this is not defined"). * Added more tests for compatability checks, statics, prototypes and ES6 expectations. Cleaned test "nested classes with super". * Changes to reflect feedback and to comment out issues that will be addressed seperately. * Clean up test/classes.coffee - Trim trailing whitespace. - Rephrase a condition to be more idiomatic. * Remove check for `super` in derived constructors In order to be usable at runtime, an extended ES class must call `super` OR return an alternative object. This check prevented the latter case, and checking for an alternative return can't be completed statically without control flow analysis. * Disallow 'super' in constructor parameter defaults There are many edge cases when combining 'super' in parameter defaults with @-parameters and bound functions (and potentially property initializers in the future). Rather than attempting to resolve these edge cases, 'super' is now explicitly disallowed in constructor parameter defaults. * Disallow @-params in derived constructors without 'super' @-parameters can't be assigned unless 'super' is called.
2017-01-13 00:55:30 -05:00
# --- CS1 classes compatability breaks ---
test "CS6 Class extends a CS1 compiled class", ->
```
// Generated by CoffeeScript 1.11.1
var BaseCS1, ExtendedCS1,
extend = function(child, parent) { for (var key in parent) { if (hasProp.call(parent, key)) child[key] = parent[key]; } function ctor() { this.constructor = child; } ctor.prototype = parent.prototype; child.prototype = new ctor(); child.__super__ = parent.prototype; return child; },
hasProp = {}.hasOwnProperty;
BaseCS1 = (function() {
function BaseCS1(drink) {
this.drink = drink;
}
BaseCS1.prototype.make = function() {
return "making a " + this.drink;
};
BaseCS1.className = function() {
return 'BaseCS1';
};
return BaseCS1;
})();
ExtendedCS1 = (function(superClass) {
extend(ExtendedCS1, superClass);
function ExtendedCS1(flavor) {
this.flavor = flavor;
ExtendedCS1.__super__.constructor.call(this, 'cafe ole');
}
ExtendedCS1.prototype.make = function() {
return "making a " + this.drink + " with " + this.flavor;
};
ExtendedCS1.className = function() {
return 'ExtendedCS1';
};
return ExtendedCS1;
})(BaseCS1);
```
class B extends BaseCS1
eq B.className(), 'BaseCS1'
b = new B('machiato')
eq b.make(), "making a machiato"
test "CS6 Class extends an extended CS1 compiled class", ->
```
// Generated by CoffeeScript 1.11.1
var BaseCS1, ExtendedCS1,
extend = function(child, parent) { for (var key in parent) { if (hasProp.call(parent, key)) child[key] = parent[key]; } function ctor() { this.constructor = child; } ctor.prototype = parent.prototype; child.prototype = new ctor(); child.__super__ = parent.prototype; return child; },
hasProp = {}.hasOwnProperty;
BaseCS1 = (function() {
function BaseCS1(drink) {
this.drink = drink;
}
BaseCS1.prototype.make = function() {
return "making a " + this.drink;
};
BaseCS1.className = function() {
return 'BaseCS1';
};
return BaseCS1;
})();
ExtendedCS1 = (function(superClass) {
extend(ExtendedCS1, superClass);
function ExtendedCS1(flavor) {
this.flavor = flavor;
ExtendedCS1.__super__.constructor.call(this, 'cafe ole');
}
ExtendedCS1.prototype.make = function() {
return "making a " + this.drink + " with " + this.flavor;
};
ExtendedCS1.className = function() {
return 'ExtendedCS1';
};
return ExtendedCS1;
})(BaseCS1);
```
class B extends ExtendedCS1
eq B.className(), 'ExtendedCS1'
b = new B('vanilla')
eq b.make(), "making a cafe ole with vanilla"
test "CS6 Class extends a CS1 compiled class with super()", ->
```
// Generated by CoffeeScript 1.11.1
var BaseCS1, ExtendedCS1,
extend = function(child, parent) { for (var key in parent) { if (hasProp.call(parent, key)) child[key] = parent[key]; } function ctor() { this.constructor = child; } ctor.prototype = parent.prototype; child.prototype = new ctor(); child.__super__ = parent.prototype; return child; },
hasProp = {}.hasOwnProperty;
BaseCS1 = (function() {
function BaseCS1(drink) {
this.drink = drink;
}
BaseCS1.prototype.make = function() {
return "making a " + this.drink;
};
BaseCS1.className = function() {
return 'BaseCS1';
};
return BaseCS1;
})();
ExtendedCS1 = (function(superClass) {
extend(ExtendedCS1, superClass);
function ExtendedCS1(flavor) {
this.flavor = flavor;
ExtendedCS1.__super__.constructor.call(this, 'cafe ole');
}
ExtendedCS1.prototype.make = function() {
return "making a " + this.drink + " with " + this.flavor;
};
ExtendedCS1.className = function() {
return 'ExtendedCS1';
};
return ExtendedCS1;
})(BaseCS1);
```
class B extends ExtendedCS1
constructor: (@shots) ->
super('caramel')
make: () ->
[CS2] Compile all super calls to ES2015 super (#4424) * Compile all super calls to ES2015 super This breaks using `super` in non-methods, meaning several tests are failing. Self-compilation still works. * Use bound functions for IIFEs containing `super` `super` can only be called directly in a method, or in an arrow function. * Fix handling of `class @A extends A` This behaviour worked 'for free' when the parent reference was being cached by the executable class body wrapper. There now needs to be special handling in place to check if the parent name matches the class name, and if so to cache the parent reference. * Fix tests broken by compiling ES2015 `super` * Disallow bare super This removes syntax support for 'bare' super calls, e.g.: class B extends A constructor: -> super `super` must now always be followed with arguments like a regular function call. This also removes the capability of implicitly forwarding arguments. The above can be equivalently be written as: class B extends A constructor: -> super arguments... * Support super with accessors `super` with following accessor(s) is now compiled to ES2015 equivalents. In particular, expressions such as `super.name`, `super[name]`, and also `super.name.prop` are all now valid, and can be used as expected as calls (i.e. `super.name()`) or in expressions (i.e. `if super.name? ...`). `super` without accessors is compiled to a constructor super call in a constructor, and otherwise, as before, to a super call to the method of the same name, i.e. speak: -> super() ...is equivalent to speak: -> super.speak() A neat side-effect of the changes is that existential calls now work properly with super, meaning `super?()` will only call if the super property exists (and is a function). This is not valid for super in constructors. * Prevent calling `super` methods with `new` This fixes a bug in the previous super handling whereby using the `new` operator with a `super` call would silently drop the `new`. This is now an explicit compiler error, as it is invalid JS at runtime. * Clean up some old super handling code This was mostly code for tracking the source classes and variables for methods, which were needed to build the old lookups on `__super__`. * Add TODO to improve bare super parse error * Add some TODOs to improve some of the class tests
2017-02-04 15:03:17 -05:00
super() + " and #{@shots} shots of espresso"
[CS2] Compile class constructors to ES2015 classes (#4354) * Compile classes to ES2015 classes Rather than compiling classes to named functions with prototype and class assignments, they are now compiled to ES2015 class declarations. Backwards compatibility has been maintained by compiling ES2015- incompatible properties as prototype or class assignments. `super` continues to be compiled as before. Where possible, classes will be compiled "bare", without an enclosing IIFE. This is possible when the class contains only ES2015 compatible expressions (methods and static methods), and has no parent (this last constraint is a result of the legacy `super` compilation, and could be removed once ES2015 `super` is being used). Classes are still assigned to variables to maintain compatibility for assigned class expressions. There are a few changes to existing functionality that could break backwards compatibility: - Derived constructors that deliberately don't call `super` are no longer possible. ES2015 derived classes can't use `this` unless the parent constructor has been called, so it's now called implicitly when not present. - As a consequence of the above, derived constructors with @ parameters or bound methods and explicit `super` calls are not allowed. The implicit `super` must be used in these cases. * Add tests to verify class interoperability with ES * Refactor class nodes to separate executable body logic Logic has been redistributed amongst the class nodes so that: - `Class` contains the logic necessary to compile an ES class declaration. - `ExecutableClassBody` contains the logic necessary to compile CS' class extensions that require an executable class body. `Class` still necessarily contains logic to determine whether an expression is valid in an ES class initializer or not. If any invalid expressions are found then `Class` will wrap itself in an `ExecutableClassBody` when compiling. * Rename `Code#static` to `Code#isStatic` This naming is more consistent with other `Code` flags. * Output anonymous classes when possible Anonymous classes can be output when: - The class has no parent. The current super compilation needs a class variable to reference. This condition will go away when ES2015 super is in use. - The class contains no bound static methods. Bound static methods have their context set to the class name. * Throw errors at compile time for async or generator constructors * Improve handling of anonymous classes Anonymous classes are now always anonymous. If a name is required (e.g. for bound static methods or derived classes) then the class is compiled in an `ExecutableClassBody` which will give the anonymous class a stable reference. * Add a `replaceInContext` method to `Node` `replaceInContext` will traverse children looking for a node for which `match` returns true. Once found, the matching node will be replaced by the result of calling `replacement`. * Separate `this` assignments from function parameters This change has been made to simplify two future changes: 1. Outputting `@`-param assignments after a `super` call. In this case it is necessary that non-`@` parameters are available before `super` is called, so destructuring has to happen before `this` assignment. 2. Compiling destructured assignment to ES6 In this case also destructuring has to happen before `this`, as destructuring can happen in the arguments list, but `this` assignment can not. A bonus side-effect is that default values for `@` params are now output as ES6 default parameters, e.g. (@a = 1) -> becomes function a (a = 1) { this.a = a; } * Change `super` handling in class constructors Inside an ES derived constructor (a constructor for a class that extends another class), it is impossible to access `this` until `super` has been called. This conflicts with CoffeeScript's `@`-param and bound method features, which compile to `this` references at the top of a function body. For example: class B extends A constructor: (@param) -> super method: => This would compile to something like: class B extends A { constructor (param) { this.param = param; this.method = bind(this.method, this); super(...arguments); } } This would break in an ES-compliant runtime as there are `this` references before the call to `super`. Before this commit we were dealing with this by injecting an implicit `super` call into derived constructors that do not already have an explicit `super` call. Furthermore, we would disallow explicit `super` calls in derived constructors that used bound methods or `@`-params, meaning the above example would need to be rewritten as: class B extends A constructor: (@param) -> method: => This would result in a call to `super(...arguments)` being generated as the first expression in `B#constructor`. Whilst this approach seems to work pretty well, and is arguably more convenient than having to manually call `super` when you don't particularly care about the arguments, it does introduce some 'magic' and separation from ES, and would likely be a pain point in a project that made use of significant constructor overriding. This commit introduces a mechanism through which `super` in constructors is 'expanded' to include any generated `this` assignments, whilst retaining the same semantics of a super call. The first example above now compiles to something like: class B extends A { constructor (param) { var ref ref = super(...arguments), this.param = param, this.method = bind(this.method, this), ref; } } * Improve `super` handling in constructors Rather than functions expanding their `super` calls, the `SuperCall` node can now be given a list of `thisAssignments` to apply when it is compiled. This allows us to use the normal compiler machinery to determine whether the `super` result needs to be cached, whether it appears inline or not, etc. * Fix anonymous classes at the top level Anonymous classes in ES are only valid within expressions. If an anonymous class is at the top level it will now be wrapped in parenthses to force it into an expression. * Re-add Parens wrapper around executable class bodies This was lost in the refactoring, but it necessary to ensure `new class ...` works as expected when there's an executable body. * Throw compiler errors for badly configured derived constructors Rather than letting them become runtime errors, the following checks are now performed when compiling a derived constructor: - The constructor **must** include a call to `super`. - The constructor **must not** reference `this` in the function body before `super` has been called. * Add some tests exercising new class behaviour - async methods in classes - `this` access after `super` in extended classes - constructor super in arrow functions - constructor functions can't be async - constructor functions can't be generators - derived constructors must call super - derived constructors can't reference `this` before calling super - generator methods in classes - 'new' target * Improve constructor `super` errors Add a check for `super` in non-extended class constructors, and explicitly mention derived constructors in the "can't reference this before super" error. * Fix compilation of multiple `super` paths in derived constructors `super` can only be called once, but it can be called conditionally from multiple locations. The chosen fix is to add the `this` assignments to every super call. * Additional class tests, added as a separate file to simplify testing and merging. Some methods are commented out because they currently throw and I'm not sure how to test for compilation errors like those. There is also one test which I deliberately left without passing, `super` in an external prototype override. This test should 'pass' but is really a variation on the failing `super only allowed in an instance method` tests above it. * Changes to the tests. Found bug in super in prototype method. fixed. * Added failing test back in, dealing with bound functions in external prototype overrides. * Located a bug in the compiler relating to assertions and escaped ES6 classes. * Move tests from classes-additional.coffee into classes.coffee; comment out console.log * Cleaned up tests and made changes based on feedback. Test at the end still has issues, but it's commented out for now. * Make HoistTarget.expand recursive It's possible that a hoisted node may itself contain hoisted nodes (e.g. a class method inside a class method). For this to work the hoisted fragments need to be expanded recursively. * Uncomment final test in classes.coffee The test case now compiles, however another issue is affecting the test due to the error for `this` before `super` triggering based on source order rather than execution order. These have been commented out for now. * Fixed last test TODOs in test/classes.coffee Turns out an expression like `this.foo = super()` won't run in JS as it attempts to lookup `this` before evaluating `super` (i.e. throws "this is not defined"). * Added more tests for compatability checks, statics, prototypes and ES6 expectations. Cleaned test "nested classes with super". * Changes to reflect feedback and to comment out issues that will be addressed seperately. * Clean up test/classes.coffee - Trim trailing whitespace. - Rephrase a condition to be more idiomatic. * Remove check for `super` in derived constructors In order to be usable at runtime, an extended ES class must call `super` OR return an alternative object. This check prevented the latter case, and checking for an alternative return can't be completed statically without control flow analysis. * Disallow 'super' in constructor parameter defaults There are many edge cases when combining 'super' in parameter defaults with @-parameters and bound functions (and potentially property initializers in the future). Rather than attempting to resolve these edge cases, 'super' is now explicitly disallowed in constructor parameter defaults. * Disallow @-params in derived constructors without 'super' @-parameters can't be assigned unless 'super' is called.
2017-01-13 00:55:30 -05:00
eq B.className(), 'ExtendedCS1'
b = new B('three')
eq b.make(), "making a cafe ole with caramel and three shots of espresso"
test 'Bound method called normally before binding is ok', ->
class Base
constructor: ->
@setProp()
eq @derivedBound(), 3
class Derived extends Base
setProp: ->
@prop = 3
derivedBound: =>
@prop
d = new Derived
test 'Bound method called as callback after super() is ok', ->
class Base
class Derived extends Base
constructor: (@prop = 3) ->
super()
f = @derivedBound
eq f(), 3
derivedBound: =>
@prop
d = new Derived
{derivedBound} = d
eq derivedBound(), 3
test 'Bound method of base class called as callback is ok', ->
class Base
constructor: (@prop = 3) ->
f = @baseBound
eq f(), 3
baseBound: =>
@prop
b = new Base
{baseBound} = b
eq baseBound(), 3
test 'Bound method of prop-named class called as callback is ok', ->
Hive = {}
class Hive.Bee
constructor: (@prop = 3) ->
f = @baseBound
eq f(), 3
baseBound: =>
@prop
b = new Hive.Bee
{baseBound} = b
eq baseBound(), 3
test 'Bound method of class with expression base class called as callback is ok', ->
calledB = no
B = ->
throw new Error if calledB
calledB = yes
class
class A extends B()
constructor: (@prop = 3) ->
super()
f = @derivedBound
eq f(), 3
derivedBound: =>
@prop
b = new A
{derivedBound} = b
eq derivedBound(), 3
test 'Bound method of class with expression class name called as callback is ok', ->
calledF = no
obj = {}
B = class
f = ->
throw new Error if calledF
calledF = yes
obj
class f().A extends B
constructor: (@prop = 3) ->
super()
g = @derivedBound
eq g(), 3
derivedBound: =>
@prop
a = new obj.A
{derivedBound} = a
eq derivedBound(), 3
test 'Bound method of anonymous child class called as callback is ok', ->
f = ->
B = class
class extends B
constructor: (@prop = 3) ->
super()
g = @derivedBound
eq g(), 3
derivedBound: =>
@prop
a = new (f())
{derivedBound} = a
eq derivedBound(), 3
test 'Bound method of immediately instantiated class with expression base class called as callback is ok', ->
calledF = no
obj = {}
B = class
f = ->
throw new Error if calledF
calledF = yes
obj
a = new class f().A extends B
constructor: (@prop = 3) ->
super()
g = @derivedBound
eq g(), 3
derivedBound: =>
@prop
{derivedBound} = a
eq derivedBound(), 3
test "#4591: super.x.y, super['x'].y", ->
class A
x:
y: 1
z: -> 2
class B extends A
constructor: ->
super()
@w = super.x.y
@v = super['x'].y
@u = super.x['y']
@t = super.x.z()
@s = super['x'].z()
@r = super.x['z']()
b = new B
eq 1, b.w
eq 1, b.v
eq 1, b.u
eq 2, b.t
eq 2, b.s
eq 2, b.r
test "#4464: backticked expressions in class body", ->
class A
`get x() { return 42; }`
class B
`get x() { return 42; }`
constructor: ->
@y = 84
a = new A
eq 42, a.x
b = new B
eq 42, b.x
eq 84, b.y
test "#4724: backticked expression in a class body with hoisted member", ->
class A
`get x() { return 42; }`
hoisted: 84
a = new A
eq 42, a.x
eq 84, a.hoisted
test "#4822: nested anonymous classes use non-conflicting variable names", ->
Class = class
@a: class
@b: 1
eq Class.a.b, 1
test "#4827: executable class body wrappers have correct context", ->
test = ->
class @A
class @B extends @A
@property = 1
o = {}
test.call o
ok typeof o.A is typeof o.B is 'function'
test "#4868: Incorrect Cant call super with @params error", ->
class A
constructor: (@func = ->) ->
@x = 1
@func()
class B extends A
constructor: ->
super -> @x = 2
a = new A
b = new B
eq 1, a.x
eq 2, b.x
class C
constructor: (@c = class) -> @c
class D extends C
constructor: ->
super class then constructor: (@a) -> @a = 3
d = new (new D).c
eq 3, d.a
test "#4609: Support new.target", ->
class A
constructor: ->
@calledAs = new.target.name
class B extends A
b = new B
eq b.calledAs, 'B'
newTarget = null
Foo = ->
newTarget = !!new.target
Foo()
eq newTarget, no
newTarget = null
new Foo()
eq newTarget, yes
2020-06-03 00:00:40 -04:00
test "#5323: new.target can be the argument of a function", ->
fn = (arg) -> arg
fn new.target
test "#5085: Bug: @ reference to class not maintained in do block", ->
thisFoo = 'initial foo'
thisBar = 'initial bar'
fn = (o) -> o.bar()
class A
@foo = 'foo assigned in class'
do => thisFoo = @foo
fn bar: => thisBar = @foo
eq thisFoo, 'foo assigned in class'
eq thisBar, 'foo assigned in class'
test "#5204: Computed class property", ->
foo = 'bar'
class A
[foo]: 'baz'
a = new A()
eq a.bar, 'baz'
eq A::bar, 'baz'
test "#5204: Static computed class property", ->
foo = 'bar'
qux = 'quux'
class A
@[foo]: 'baz'
@[qux]: -> 3
eq A.bar, 'baz'
eq A.quux(), 3