nodes.coffee | |
|---|---|
if process?
process.mixin require 'scope'
else
this.exports: this | |
| Some helper functions | |
| Tabs are two spaces for pretty printing. | TAB: ' '
TRAILING_WHITESPACE: /\s+$/gm |
| Keep the identifier regex in sync with the Lexer. | IDENTIFIER: /^[a-zA-Z$_](\w|\$)*$/ |
| Merge objects. | merge: (options, overrides) ->
fresh: {}
(fresh[key]: val) for key, val of options
(fresh[key]: val) for key, val of overrides if overrides
fresh |
| Trim out all falsy values from an array. | compact: (array) -> item for item in array when item |
| Return a completely flattened version of an array. | flatten: (array) ->
memo: []
for item in array
if item instanceof Array then memo: memo.concat(item) else memo.push(item)
memo |
| Delete a key from an object, returning the value. | del: (obj, key) ->
val: obj[key]
delete obj[key]
val |
| Quickie helper for a generated LiteralNode. | literal: (name) ->
new LiteralNode(name) |
| Mark a node as a statement, or a statement only. | statement: (klass, only) ->
klass::is_statement: -> true
(klass::is_statement_only: -> true) if only |
| The abstract base class for all CoffeeScript nodes. All nodes are implement a "compile_node" method, which performs the code generation for that node. To compile a node, call the "compile" method, which wraps "compile_node" in some extra smarts, to know when the generated code should be wrapped up in a closure. An options hash is passed and cloned throughout, containing messages from higher in the AST, information about the current scope, and indentation level. | exports.BaseNode: class BaseNode |
| This is extremely important -- we convert JS statements into expressions by wrapping them in a closure, only if it's possible, and we're not at the top level of a block (which would be unnecessary), and we haven't already been asked to return the result. | compile: (o) ->
@options: merge o or {}
@indent: o.indent
del @options, 'operation' unless @operation_sensitive()
top: if @top_sensitive() then @options.top else del @options, 'top'
closure: @is_statement() and not @is_statement_only() and not top and
not @options.returns and not (this instanceof CommentNode) and
not @contains (node) -> node.is_statement_only()
if closure then @compile_closure(@options) else @compile_node(@options) |
| Statements converted into expressions share scope with their parent closure, to preserve JavaScript-style lexical scope. | compile_closure: (o) ->
@indent: o.indent
o.shared_scope: o.scope
ClosureNode.wrap(this).compile(o) |
| If the code generation wishes to use the result of a complex expression in multiple places, ensure that the expression is only ever evaluated once. | compile_reference: (o) ->
reference: literal(o.scope.free_variable())
compiled: new AssignNode(reference, this)
[compiled, reference] |
| Quick short method for the current indentation level, plus tabbing in. | idt: (tabs) ->
idt: (@indent || '')
idt += TAB for i in [0...(tabs or 0)]
idt |
| Does this node, or any of its children, contain a node of a certain kind? | contains: (block) ->
for node in @children
return true if block(node)
return true if node.contains and node.contains block
false |
| Perform an in-order traversal of the AST. | traverse: (block) ->
for node in @children
block node
node.traverse block if node.traverse |
| toString representation of the node, for inspecting the parse tree. | toString: (idt) ->
idt ||= ''
'\n' + idt + @type + (child.toString(idt + TAB) for child in @children).join('') |
| Default implementations of the common node methods. | unwrap: -> this
children: []
is_statement: -> false
is_statement_only: -> false
top_sensitive: -> false
operation_sensitive: -> false |
| A collection of nodes, each one representing an expression. | exports.Expressions: class Expressions extends BaseNode
type: 'Expressions'
constructor: (nodes) ->
@children: @expressions: compact flatten nodes or [] |
| Tack an expression on to the end of this expression list. | push: (node) ->
@expressions.push(node)
this |
| Tack an expression on to the beginning of this expression list. | unshift: (node) ->
@expressions.unshift(node)
this |
| If this Expressions consists of a single node, pull it back out. | unwrap: ->
if @expressions.length is 1 then @expressions[0] else this |
| Is this an empty block of code? | empty: ->
@expressions.length is 0 |
| Is the node last in this block of expressions? | is_last: (node) ->
l: @expressions.length
last_index: if @expressions[l - 1] instanceof CommentNode then 2 else 1
node is @expressions[l - last_index]
compile: (o) ->
o ||= {}
if o.scope then super(o) else @compile_root(o) |
| Compile each expression in the Expressions body. | compile_node: (o) ->
(@compile_expression(node, merge(o)) for node in @expressions).join("\n") |
| If this is the top-level Expressions, wrap everything in a safety closure. | compile_root: (o) ->
o.indent: @indent: indent: if o.no_wrap then '' else TAB
o.scope: new Scope(null, this, null)
code: if o.globals then @compile_node(o) else @compile_with_declarations(o)
code: code.replace(TRAILING_WHITESPACE, '')
if o.no_wrap then code else "(function(){\n$code\n})();\n" |
| Compile the expressions body, with declarations of all inner variables pushed up to the top. | compile_with_declarations: (o) ->
code: @compile_node(o)
args: @contains (node) -> node instanceof ValueNode and node.is_arguments()
code: "${@idt()}arguments = Array.prototype.slice.call(arguments, 0);\n$code" if args
code: "${@idt()}var ${o.scope.compiled_assignments()};\n$code" if o.scope.has_assignments(this)
code: "${@idt()}var ${o.scope.compiled_declarations()};\n$code" if o.scope.has_declarations(this)
code |
| Compiles a single expression within the expressions body. | compile_expression: (node, o) ->
@indent: o.indent
stmt: node.is_statement() |
| We need to return the result if this is the last node in the expressions body. | returns: del(o, 'returns') and @is_last(node) and not node.is_statement_only() |
| Return the regular compile of the node, unless we need to return the result. | return (if stmt then '' else @idt()) + node.compile(merge(o, {top: true})) + (if stmt then '' else ';') unless returns |
| If it's a statement, the node knows how to return itself. | return node.compile(merge(o, {returns: true})) if node.is_statement() |
| Otherwise, we can just return the value of the expression. | return "${@idt()}return ${node.compile(o)};" |
| Wrap up a node as an Expressions, unless it already is one. | Expressions.wrap: (nodes) ->
return nodes[0] if nodes.length is 1 and nodes[0] instanceof Expressions
new Expressions(nodes)
statement Expressions |
| Literals are static values that can be passed through directly into JavaScript without translation, eg.: strings, numbers, true, false, null... | exports.LiteralNode: class LiteralNode extends BaseNode
type: 'Literal'
constructor: (value) ->
@value: value |
| Break and continue must be treated as statements -- they lose their meaning when wrapped in a closure. | is_statement: ->
@value is 'break' or @value is 'continue'
is_statement_only: LiteralNode::is_statement
compile_node: (o) ->
idt: if @is_statement() then @idt() else ''
end: if @is_statement() then ';' else ''
"$idt$@value$end"
toString: (idt) ->
" \"$@value\"" |
| Return an expression, or wrap it in a closure and return it. | exports.ReturnNode: class ReturnNode extends BaseNode
type: 'Return'
constructor: (expression) ->
@children: [@expression: expression]
compile_node: (o) ->
return @expression.compile(merge(o, {returns: true})) if @expression.is_statement()
"${@idt()}return ${@expression.compile(o)};"
statement ReturnNode, true |
| A value, indexed or dotted into, or vanilla. | exports.ValueNode: class ValueNode extends BaseNode
type: 'Value'
SOAK: " == undefined ? undefined : "
constructor: (base, properties) ->
@children: flatten [@base: base, @properties: (properties or [])]
push: (prop) ->
@properties.push(prop)
@children.push(prop)
this
operation_sensitive: ->
true
has_properties: ->
!!@properties.length
is_array: ->
@base instanceof ArrayNode and not @has_properties()
is_object: ->
@base instanceof ObjectNode and not @has_properties()
is_splice: ->
@has_properties() and @properties[@properties.length - 1] instanceof SliceNode
is_arguments: ->
@base.value is 'arguments'
unwrap: ->
if @properties.length then this else @base |
| Values are statements if their base is a statement. | is_statement: ->
@base.is_statement and @base.is_statement() and not @has_properties()
compile_node: (o) ->
soaked: false
only: del(o, 'only_first')
op: del(o, 'operation')
props: if only then @properties[0...@properties.length - 1] else @properties
baseline: @base.compile o
baseline: "($baseline)" if @base instanceof ObjectNode and @has_properties()
complete: @last: baseline
for prop in props
@source: baseline
if prop.soak_node
soaked: true
if @base instanceof CallNode and prop is props[0]
temp: o.scope.free_variable()
complete: "($temp = $complete)$@SOAK" + (baseline: temp + prop.compile(o))
else
complete: complete + @SOAK + (baseline += prop.compile(o))
else
part: prop.compile(o)
baseline += part
complete += part
@last: part
if op and soaked then "($complete)" else complete |
| Pass through CoffeeScript comments into JavaScript comments at the same position. | exports.CommentNode: class CommentNode extends BaseNode
type: 'Comment'
constructor: (lines) ->
@lines: lines
this
compile_node: (o) ->
"${@idt()}//" + @lines.join("\n${@idt()}//")
statement CommentNode |
| Node for a function invocation. Takes care of converting super() calls into calls against the prototype's function of the same name. | exports.CallNode: class CallNode extends BaseNode
type: 'Call'
constructor: (variable, args) ->
@children: flatten [@variable: variable, @args: (args or [])]
@prefix: ''
new_instance: ->
@prefix: 'new '
this
push: (arg) ->
@args.push(arg)
@children.push(arg)
this |
| Compile a vanilla function call. | compile_node: (o) ->
return @compile_splat(o) if @args[@args.length - 1] instanceof SplatNode
args: (arg.compile(o) for arg in @args).join(', ')
return @compile_super(args, o) if @variable is 'super'
"$@prefix${@variable.compile(o)}($args)" |
| Compile a call against the superclass's implementation of the current function. | compile_super: (args, o) ->
methname: o.scope.method.name
meth: if o.scope.method.proto
"${o.scope.method.proto}.__superClass__.$methname"
else
"$methname.__superClass__.constructor"
"$meth.call(this${ if args.length then ', ' else '' }$args)" |
| Compile a function call being passed variable arguments. | compile_splat: (o) ->
meth: @variable.compile o
obj: @variable.source or 'this'
if obj.match(/\(/)
temp: o.scope.free_variable()
obj: temp
meth: "($temp = ${ @variable.source })${ @variable.last }"
args: for arg, i in @args
code: arg.compile o
code: if arg instanceof SplatNode then code else "[$code]"
if i is 0 then code else ".concat($code)"
"$@prefix$meth.apply($obj, ${ args.join('') })" |
| Node to extend an object's prototype with an ancestor object. After goog.inherits from the Closure Library. | exports.ExtendsNode: class ExtendsNode extends BaseNode
type: 'Extends'
code: '''
function(child, parent) {
var ctor = function(){ };
ctor.prototype = parent.prototype;
child.__superClass__ = parent.prototype;
child.prototype = new ctor();
child.prototype.constructor = child;
}
'''
constructor: (child, parent) ->
@children: [@child: child, @parent: parent] |
| Hooking one constructor into another's prototype chain. | compile_node: (o) ->
o.scope.assign('__extends', @code, true)
ref: new ValueNode literal('__extends')
call: new CallNode ref, [@child, @parent]
call.compile(o) |
| A dotted accessor into a part of a value, or the :: shorthand for an accessor into the object's prototype. | exports.AccessorNode: class AccessorNode extends BaseNode
type: 'Accessor'
constructor: (name, tag) ->
@children: [@name: name]
@prototype: tag is 'prototype'
@soak_node: tag is 'soak'
this
compile_node: (o) ->
'.' + (if @prototype then 'prototype.' else '') + @name.compile(o) |
| An indexed accessor into a part of an array or object. | exports.IndexNode: class IndexNode extends BaseNode
type: 'Index'
constructor: (index, tag) ->
@children: [@index: index]
@soak_node: tag is 'soak'
compile_node: (o) ->
idx: @index.compile o
"[$idx]" |
| A range literal. Ranges can be used to extract portions (slices) of arrays, or to specify a range for list comprehensions. | exports.RangeNode: class RangeNode extends BaseNode
type: 'Range'
constructor: (from, to, exclusive) ->
@children: [@from: from, @to: to]
@exclusive: !!exclusive
compile_variables: (o) ->
@indent: o.indent
[@from_var, @to_var]: [o.scope.free_variable(), o.scope.free_variable()]
[from, to]: [@from.compile(o), @to.compile(o)]
"$@from_var = $from; $@to_var = $to;\n${@idt()}"
compile_node: (o) ->
return @compile_array(o) unless o.index
idx: del o, 'index'
step: del o, 'step'
vars: "$idx = $@from_var"
step: if step then step.compile(o) else '1'
equals: if @exclusive then '' else '='
intro: "($@from_var <= $@to_var ? $idx"
compare: "$intro <$equals $@to_var : $idx >$equals $@to_var)"
incr: "$intro += $step : $idx -= $step)"
"$vars; $compare; $incr" |
| Expand the range into the equivalent array, if it's not being used as part of a comprehension, slice, or splice. TODO: This generates pretty ugly code ... shrink it. | compile_array: (o) ->
name: o.scope.free_variable()
body: Expressions.wrap([literal(name)])
arr: Expressions.wrap([new ForNode(body, {source: (new ValueNode(this))}, literal(name))])
(new ParentheticalNode(new CallNode(new CodeNode([], arr)))).compile(o) |
| An array slice literal. Unlike JavaScript's Array#slice, the second parameter specifies the index of the end of the slice (just like the first parameter) is the index of the beginning. | exports.SliceNode: class SliceNode extends BaseNode
type: 'Slice'
constructor: (range) ->
@children: [@range: range]
this
compile_node: (o) ->
from: @range.from.compile(o)
to: @range.to.compile(o)
plus_part: if @range.exclusive then '' else ' + 1'
".slice($from, $to$plus_part)" |
| An object literal. | exports.ObjectNode: class ObjectNode extends BaseNode
type: 'Object'
constructor: (props) ->
@children: @objects: @properties: props or [] |
| All the mucking about with commas is to make sure that CommentNodes and AssignNodes get interleaved correctly, with no trailing commas or commas affixed to comments. TODO: Extract this and add it to ArrayNode. | compile_node: (o) ->
o.indent: @idt(1)
non_comments: prop for prop in @properties when not (prop instanceof CommentNode)
last_noncom: non_comments[non_comments.length - 1]
props: for prop, i in @properties
join: ",\n"
join: "\n" if (prop is last_noncom) or (prop instanceof CommentNode)
join: '' if i is @properties.length - 1
indent: if prop instanceof CommentNode then '' else @idt(1)
indent + prop.compile(o) + join
props: props.join('')
inner: if props then '\n' + props + '\n' + @idt() else ''
"{$inner}" |
| A class literal, including optional superclass and constructor. | exports.ClassNode: class ClassNode extends BaseNode
type: 'Class'
constructor: (variable, parent, props) ->
@children: compact flatten [@variable: variable, @parent: parent, @properties: props or []]
compile_node: (o) ->
extension: @parent and new ExtendsNode(@variable, @parent)
constructor: null
props: new Expressions()
o.top: true
ret: del o, 'returns'
for prop in @properties
if prop.variable and prop.variable.base.value is 'constructor'
func: prop.value
func.body.push(new ReturnNode(literal('this')))
constructor: new AssignNode(@variable, func)
else
if prop.variable
val: new ValueNode(@variable, [new AccessorNode(prop.variable, 'prototype')])
prop: new AssignNode(val, prop.value)
props.push prop
if not constructor
if @parent
applied: new ValueNode(@parent, [new AccessorNode(literal('apply'))])
constructor: new AssignNode(@variable, new CodeNode([], new Expressions([
new CallNode(applied, [literal('this'), literal('arguments')])
])))
else
constructor: new AssignNode(@variable, new CodeNode())
construct: @idt() + constructor.compile(o) + ';\n'
props: if props.empty() then '' else props.compile(o) + '\n'
extension: if extension then @idt() + extension.compile(o) + ';\n' else ''
returns: if ret then '\n' + @idt() + 'return ' + @variable.compile(o) + ';' else ''
"$construct$extension$props$returns"
statement ClassNode |
| An array literal. | exports.ArrayNode: class ArrayNode extends BaseNode
type: 'Array'
constructor: (objects) ->
@children: @objects: objects or []
compile_node: (o) ->
o.indent: @idt(1)
objects: for obj, i in @objects
code: obj.compile(o)
if obj instanceof CommentNode
"\n$code\n${o.indent}"
else if i is @objects.length - 1
code
else
"$code, "
objects: objects.join('')
ending: if objects.indexOf('\n') >= 0 then "\n${@idt()}]" else ']'
"[$objects$ending" |
| A faux-node that is never created by the grammar, but is used during code generation to generate a quick "array.push(value)" tree of nodes. | PushNode: exports.PushNode: {
wrap: (array, expressions) ->
expr: expressions.unwrap()
return expressions if expr.is_statement_only() or expr.contains (n) -> n.is_statement_only()
Expressions.wrap([new CallNode(
new ValueNode(literal(array), [new AccessorNode(literal('push'))]), [expr]
)])
} |
| A faux-node used to wrap an expressions body in a closure. | ClosureNode: exports.ClosureNode: {
wrap: (expressions, statement) ->
func: new ParentheticalNode(new CodeNode([], Expressions.wrap([expressions])))
call: new CallNode(new ValueNode(func, [new AccessorNode(literal('call'))]), [literal('this')])
if statement then Expressions.wrap([call]) else call
} |
| Setting the value of a local variable, or the value of an object property. | exports.AssignNode: class AssignNode extends BaseNode
type: 'Assign'
PROTO_ASSIGN: /^(\S+)\.prototype/
LEADING_DOT: /^\.(prototype\.)?/
constructor: (variable, value, context) ->
@children: [@variable: variable, @value: value]
@context: context
top_sensitive: ->
true
is_value: ->
@variable instanceof ValueNode
is_statement: ->
@is_value() and (@variable.is_array() or @variable.is_object())
compile_node: (o) ->
top: del o, 'top'
return @compile_pattern_match(o) if @is_statement()
return @compile_splice(o) if @is_value() and @variable.is_splice()
stmt: del o, 'as_statement'
name: @variable.compile(o)
last: if @is_value() then @variable.last.replace(@LEADING_DOT, '') else name
match: name.match(@PROTO_ASSIGN)
proto: match and match[1]
if @value instanceof CodeNode
@value.name: last if last.match(IDENTIFIER)
@value.proto: proto if proto
val: @value.compile o
return "$name: $val" if @context is 'object'
o.scope.find name unless @is_value() and @variable.has_properties()
val: "$name = $val"
return "${@idt()}$val;" if stmt
val: "($val)" if not top or o.returns
val: "${@idt()}return $val" if o.returns
val |
| Implementation of recursive pattern matching, when assigning array or object literals to a value. Peeks at their properties to assign inner names. See: http://wiki.ecmascript.org/doku.php?id=harmony:destructuring | compile_pattern_match: (o) ->
val_var: o.scope.free_variable()
value: if @value.is_statement() then ClosureNode.wrap(@value) else @value
assigns: ["${@idt()}$val_var = ${ value.compile(o) };"]
o.top: true
o.as_statement: true
for obj, i in @variable.base.objects
idx: i
[obj, idx]: [obj.value, obj.variable.base] if @variable.is_object()
access_class: if @variable.is_array() then IndexNode else AccessorNode
if obj instanceof SplatNode
val: literal(obj.compile_value(o, val_var, @variable.base.objects.indexOf(obj)))
else
idx: literal(idx) unless typeof idx is 'object'
val: new ValueNode(literal(val_var), [new access_class(idx)])
assigns.push(new AssignNode(obj, val).compile(o))
code: assigns.join("\n")
code += "\n${@idt()}return ${ @variable.compile(o) };" if o.returns
code
compile_splice: (o) ->
name: @variable.compile(merge(o, {only_first: true}))
l: @variable.properties.length
range: @variable.properties[l - 1].range
plus: if range.exclusive then '' else ' + 1'
from: range.from.compile(o)
to: range.to.compile(o) + ' - ' + from + plus
val: @value.compile(o)
"$name.splice.apply($name, [$from, $to].concat($val))" |
| A function definition. The only node that creates a new Scope. A CodeNode does not have any children -- they're within the new scope. | exports.CodeNode: class CodeNode extends BaseNode
type: 'Code'
constructor: (params, body, tag) ->
@params: params or []
@body: body or new Expressions()
@bound: tag is 'boundfunc'
compile_node: (o) ->
shared_scope: del o, 'shared_scope'
top: del o, 'top'
o.scope: shared_scope or new Scope(o.scope, @body, this)
o.returns: true
o.top: true
o.indent: @idt(if @bound then 2 else 1)
del o, 'no_wrap'
del o, 'globals'
if @params[@params.length - 1] instanceof SplatNode
splat: @params.pop()
splat.index: @params.length
@body.unshift(splat)
params: (param.compile(o) for param in @params)
(o.scope.parameter(param)) for param in params
code: if @body.expressions.length then "\n${ @body.compile_with_declarations(o) }\n" else ''
name_part: if @name then ' ' + @name else ''
func: "function${ if @bound then '' else name_part }(${ params.join(', ') }) {$code${@idt(if @bound then 1 else 0)}}"
func: "($func)" if top and not @bound
return func unless @bound
inner: "(function$name_part() {\n${@idt(2)}return __func.apply(__this, arguments);\n${@idt(1)}});"
"(function(__this) {\n${@idt(1)}var __func = $func;\n${@idt(1)}return $inner\n${@idt()}})(this)"
top_sensitive: ->
true
real_children: ->
flatten [@params, @body.expressions]
traverse: (block) ->
block this
block(child) for child in @real_children()
toString: (idt) ->
idt ||= ''
children: (child.toString(idt + TAB) for child in @real_children()).join('')
"\n$idt$children" |
| A splat, either as a parameter to a function, an argument to a call, or in a destructuring assignment. | exports.SplatNode: class SplatNode extends BaseNode
type: 'Splat'
constructor: (name) ->
name: literal(name) unless name.compile
@children: [@name: name]
compile_node: (o) ->
if @index? then @compile_param(o) else @name.compile(o)
compile_param: (o) ->
name: @name.compile(o)
o.scope.find name
"$name = Array.prototype.slice.call(arguments, $@index)"
compile_value: (o, name, index) ->
"Array.prototype.slice.call($name, $index)" |
| A while loop, the only sort of low-level loop exposed by CoffeeScript. From it, all other loops can be manufactured. | exports.WhileNode: class WhileNode extends BaseNode
type: 'While'
constructor: (condition, opts) ->
@children:[@condition: condition]
@filter: opts and opts.filter
add_body: (body) ->
@children.push @body: body
this
top_sensitive: ->
true
compile_node: (o) ->
returns: del(o, 'returns')
top: del(o, 'top') and not returns
o.indent: @idt(1)
o.top: true
cond: @condition.compile(o)
set: ''
if not top
rvar: o.scope.free_variable()
set: "${@idt()}$rvar = [];\n"
@body: PushNode.wrap(rvar, @body) if @body
post: if returns then "\n${@idt()}return $rvar;" else ''
pre: "$set${@idt()}while ($cond)"
return "$pre null;$post" if not @body
@body: Expressions.wrap([new IfNode(@filter, @body)]) if @filter
"$pre {\n${ @body.compile(o) }\n${@idt()}}$post"
statement WhileNode |
| Simple Arithmetic and logical operations. Performs some conversion from CoffeeScript operations into their JavaScript equivalents. | exports.OpNode: class OpNode extends BaseNode
type: 'Op'
CONVERSIONS: {
'==': '==='
'!=': '!=='
'and': '&&'
'or': '||'
'is': '==='
'isnt': '!=='
'not': '!'
}
CHAINABLE: ['<', '>', '>=', '<=', '===', '!==']
ASSIGNMENT: ['||=', '&&=', '?=']
PREFIX_OPERATORS: ['typeof', 'delete']
constructor: (operator, first, second, flip) ->
@type += ' ' + operator
@children: compact [@first: first, @second: second]
@operator: @CONVERSIONS[operator] or operator
@flip: !!flip
is_unary: ->
not @second
is_chainable: ->
@CHAINABLE.indexOf(@operator) >= 0
compile_node: (o) ->
o.operation: true
return @compile_chain(o) if @is_chainable() and @first.unwrap() instanceof OpNode and @first.unwrap().is_chainable()
return @compile_assignment(o) if @ASSIGNMENT.indexOf(@operator) >= 0
return @compile_unary(o) if @is_unary()
return @compile_existence(o) if @operator is '?'
[@first.compile(o), @operator, @second.compile(o)].join ' ' |
| Mimic Python's chained comparisons. See: http://docs.python.org/reference/expressions.html#notin | compile_chain: (o) ->
shared: @first.unwrap().second
[@first.second, shared]: shared.compile_reference(o) if shared instanceof CallNode
[first, second, shared]: [@first.compile(o), @second.compile(o), shared.compile(o)]
"($first) && ($shared $@operator $second)"
compile_assignment: (o) ->
[first, second]: [@first.compile(o), @second.compile(o)]
o.scope.find(first) if first.match(IDENTIFIER)
return "$first = ${ ExistenceNode.compile_test(o, @first) } ? $first : $second" if @operator is '?='
"$first = $first ${ @operator.substr(0, 2) } $second"
compile_existence: (o) ->
[first, second]: [@first.compile(o), @second.compile(o)]
test: ExistenceNode.compile_test(o, @first)
"$test ? $first : $second"
compile_unary: (o) ->
space: if @PREFIX_OPERATORS.indexOf(@operator) >= 0 then ' ' else ''
parts: [@operator, space, @first.compile(o)]
parts: parts.reverse() if @flip
parts.join('') |
| A try/catch/finally block. | exports.TryNode: class TryNode extends BaseNode
type: 'Try'
constructor: (attempt, error, recovery, ensure) ->
@children: compact [@attempt: attempt, @recovery: recovery, @ensure: ensure]
@error: error
this
compile_node: (o) ->
o.indent: @idt(1)
o.top: true
attempt_part: @attempt.compile(o)
error_part: if @error then " (${ @error.compile(o) }) " else ' '
catch_part: "${ (@recovery or '') and ' catch' }$error_part{\n${ @recovery.compile(o) }\n${@idt()}}"
finally_part: (@ensure or '') and ' finally {\n' + @ensure.compile(merge(o, {returns: null})) + "\n${@idt()}}"
"${@idt()}try {\n$attempt_part\n${@idt()}}$catch_part$finally_part"
statement TryNode |
| Throw an exception. | exports.ThrowNode: class ThrowNode extends BaseNode
type: 'Throw'
constructor: (expression) ->
@children: [@expression: expression]
compile_node: (o) ->
"${@idt()}throw ${@expression.compile(o)};"
statement ThrowNode, true |
| Check an expression for existence (meaning not null or undefined). | exports.ExistenceNode: class ExistenceNode extends BaseNode
type: 'Existence'
constructor: (expression) ->
@children: [@expression: expression]
compile_node: (o) ->
ExistenceNode.compile_test(o, @expression)
ExistenceNode.compile_test: (o, variable) ->
[first, second]: [variable, variable]
if variable instanceof CallNode or (variable instanceof ValueNode and variable.has_properties())
[first, second]: variable.compile_reference(o)
[first, second]: [first.compile(o), second.compile(o)]
"(typeof $first !== \"undefined\" && $second !== null)" |
| An extra set of parentheses, specified explicitly in the source. | exports.ParentheticalNode: class ParentheticalNode extends BaseNode
type: 'Paren'
constructor: (expression) ->
@children: [@expression: expression]
is_statement: ->
@expression.is_statement()
compile_node: (o) ->
code: @expression.compile(o)
return code if @is_statement()
l: code.length
code: code.substr(o, l-1) if code.substr(l-1, 1) is ';'
"($code)" |
| The replacement for the for loop is an array comprehension (that compiles) into a for loop. Also acts as an expression, able to return the result of the comprehenion. Unlike Python array comprehensions, it's able to pass the current index of the loop as a second parameter. | exports.ForNode: class ForNode extends BaseNode
type: 'For'
constructor: (body, source, name, index) ->
@body: body
@name: name
@index: index or null
@source: source.source
@filter: source.filter
@step: source.step
@object: !!source.object
[@name, @index]: [@index, @name] if @object
@children: compact [@body, @source, @filter]
top_sensitive: ->
true
compile_node: (o) ->
top_level: del(o, 'top') and not o.returns
range: @source instanceof ValueNode and @source.base instanceof RangeNode and not @source.properties.length
source: if range then @source.base else @source
scope: o.scope
name: @name and @name.compile o
index: @index and @index.compile o
name_found: name and scope.find name
index_found: index and scope.find index
body_dent: @idt(1)
rvar: scope.free_variable() unless top_level
svar: scope.free_variable()
ivar: if range then name else index or scope.free_variable()
var_part: ''
body: Expressions.wrap([@body])
if range
index_var: scope.free_variable()
source_part: source.compile_variables o
for_part: source.compile merge o, {index: ivar, step: @step}
for_part: "$index_var = 0, $for_part, $index_var++"
else
index_var: null
source_part: "$svar = ${ @source.compile(o) };\n${@idt()}"
var_part: "$body_dent$name = $svar[$ivar];\n" if name
if not @object
lvar: scope.free_variable()
step_part: if @step then "$ivar += ${ @step.compile(o) }" else "$ivar++"
for_part: "$ivar = 0, $lvar = $svar.length; $ivar < $lvar; $step_part"
set_result: if rvar then @idt() + rvar + ' = []; ' else @idt()
return_result: rvar or ''
body: ClosureNode.wrap(body, true) if top_level and @contains (n) -> n instanceof CodeNode
body: PushNode.wrap(rvar, body) unless top_level
if o.returns
return_result: 'return ' + return_result
del o, 'returns'
body: new IfNode(@filter, body, null, {statement: true}) if @filter
else if @filter
body: Expressions.wrap([new IfNode(@filter, body)])
if @object
o.scope.assign('__hasProp', 'Object.prototype.hasOwnProperty', true)
for_part: "$ivar in $svar) { if (__hasProp.call($svar, $ivar)"
return_result: "\n${@idt()}$return_result;" unless top_level
body: body.compile(merge(o, {indent: body_dent, top: true}))
vars: if range then name else "$name, $ivar"
close: if @object then '}}\n' else '}\n'
"$set_result${source_part}for ($for_part) {\n$var_part$body\n${@idt()}$close${@idt()}$return_result"
statement ForNode |
| If/else statements. Switch/whens get compiled into these. Acts as an expression by pushing down requested returns to the expression bodies. Single-expression IfNodes are compiled into ternary operators if possible, because ternaries are first-class returnable assignable expressions. | exports.IfNode: class IfNode extends BaseNode
type: 'If'
constructor: (condition, body, else_body, tags) ->
@condition: condition
@body: body and body.unwrap()
@else_body: else_body and else_body.unwrap()
@children: compact [@condition, @body, @else_body]
@tags: tags or {}
@multiple: true if @condition instanceof Array
@condition: new OpNode('!', new ParentheticalNode(@condition)) if @tags.invert
push: (else_body) ->
eb: else_body.unwrap()
if @else_body then @else_body.push(eb) else @else_body: eb
this
force_statement: ->
@tags.statement: true
this |
| Tag a chain of IfNodes with their switch condition for equality. | rewrite_condition: (expression) ->
@switcher: expression
this |
| Rewrite a chain of IfNodes with their switch condition for equality. | rewrite_switch: (o) ->
assigner: @switcher
if not (@switcher.unwrap() instanceof LiteralNode)
variable: literal(o.scope.free_variable())
assigner: new AssignNode(variable, @switcher)
@switcher: variable
@condition: if @multiple
for cond, i in @condition
new OpNode('is', (if i is 0 then assigner else @switcher), cond)
else
new OpNode('is', assigner, @condition)
@else_body.rewrite_condition(@switcher) if @is_chain()
this |
| Rewrite a chain of IfNodes to add a default case as the final else. | add_else: (exprs, statement) ->
if @is_chain()
@else_body.add_else exprs, statement
else
exprs: exprs.unwrap() unless statement
@children.push @else_body: exprs
this |
| If the else_body is an IfNode itself, then we've got an if-else chain. | is_chain: ->
@chain ||= @else_body and @else_body instanceof IfNode |
| The IfNode only compiles into a statement if either of the bodies needs to be a statement. | is_statement: ->
@statement ||= !!(@comment or @tags.statement or @body.is_statement() or (@else_body and @else_body.is_statement()))
compile_condition: (o) ->
(cond.compile(o) for cond in flatten([@condition])).join(' || ')
compile_node: (o) ->
if @is_statement() then @compile_statement(o) else @compile_ternary(o) |
| Compile the IfNode as a regular if-else statement. Flattened chains force sub-else bodies into statement form. | compile_statement: (o) ->
@rewrite_switch(o) if @switcher
child: del o, 'chain_child'
cond_o: merge o
del cond_o, 'returns'
o.indent: @idt(1)
o.top: true
if_dent: if child then '' else @idt()
com_dent: if child then @idt() else ''
prefix: if @comment then "${ @comment.compile(cond_o) }\n$com_dent" else ''
body: Expressions.wrap([@body]).compile(o)
if_part: "$prefix${if_dent}if (${ @compile_condition(cond_o) }) {\n$body\n${@idt()}}"
return if_part unless @else_body
else_part: if @is_chain()
' else ' + @else_body.compile(merge(o, {indent: @idt(), chain_child: true}))
else
" else {\n${ Expressions.wrap([@else_body]).compile(o) }\n${@idt()}}"
"$if_part$else_part" |
| Compile the IfNode into a ternary operator. | compile_ternary: (o) ->
if_part: @condition.compile(o) + ' ? ' + @body.compile(o)
else_part: if @else_body then @else_body.compile(o) else 'null'
"$if_part : $else_part"
|