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and now with if/else statements, CoffeeScript-in-CoffeeScript is language-complete -- now for the shakedown cruise

This commit is contained in:
Jeremy Ashkenas 2010-02-10 21:40:10 -05:00
parent 13d3b3a3ce
commit 38e1991f82
5 changed files with 194 additions and 5 deletions
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111
lib/coffee_script/nodes.js
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@ -1,5 +1,5 @@
(function(){
var AccessorNode, ArrayNode, AssignNode, CallNode, ClosureNode, CodeNode, CommentNode, ExistenceNode, Expressions, ExtendsNode, ForNode, IDENTIFIER, IndexNode, LiteralNode, Node, ObjectNode, OpNode, ParentheticalNode, PushNode, RangeNode, ReturnNode, SliceNode, SplatNode, TAB, TRAILING_WHITESPACE, ThisNode, ThrowNode, TryNode, ValueNode, WhileNode, any, compact, del, dup, flatten, inherit, merge, statement;
var AccessorNode, ArrayNode, AssignNode, CallNode, ClosureNode, CodeNode, CommentNode, ExistenceNode, Expressions, ExtendsNode, ForNode, IDENTIFIER, IfNode, IndexNode, LiteralNode, Node, ObjectNode, OpNode, ParentheticalNode, PushNode, RangeNode, ReturnNode, SliceNode, SplatNode, TAB, TRAILING_WHITESPACE, ThisNode, ThrowNode, TryNode, ValueNode, WhileNode, any, compact, del, dup, flatten, inherit, merge, statement;
var __hasProp = Object.prototype.hasOwnProperty;
process.mixin(require('./scope'));
// The abstract base class for all CoffeeScript nodes.
@ -1290,4 +1290,113 @@
}
}));
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.
IfNode = (exports.IfNode = inherit(Node, {
constructor: function constructor(condition, body, else_body, tags) {
this.condition = condition;
this.body = body && body.unwrap();
this.else_body = else_body && else_body.unwrap();
this.children = [this.condition, this.body, this.else_body];
this.tags = tags || {
};
if (this.condition instanceof Array) {
this.multiple = true;
}
if (this.tags.invert) {
this.condition = new OpNode('!', new ParentheticalNode(this.condition));
}
return this;
},
push: function push(else_body) {
var eb;
eb = else_body.unwrap();
this.else_body ? this.else_body.push(eb) : (this.else_body = eb);
return this;
},
force_statement: function force_statement() {
this.tags.statement = true;
return this;
},
// Rewrite a chain of IfNodes with their switch condition for equality.
rewrite_condition: function rewrite_condition(expression) {
var __a, __b, __c, cond;
this.condition = (function() {
if (this.multiple) {
__a = []; __b = this.condition;
for (__c = 0; __c < __b.length; __c++) {
cond = __b[__c];
__a.push(new OpNode('is', expression, cond));
}
return __a;
} else {
return new OpNode('is', expression, this.condition);
}
}).call(this);
if (this.is_chain()) {
this.else_body.rewrite_condition(expression);
}
return this;
},
// Rewrite a chain of IfNodes to add a default case as the final else.
add_else: function add_else(exprs) {
this.is_chain() ? this.else_body.add_else(exprs) : (this.else_body = exprs && exprs.unwrap());
return this;
},
// If the else_body is an IfNode itself, then we've got an if-else chain.
is_chain: function is_chain() {
return this.chain = this.chain || this.else_body && this.else_body instanceof IfNode;
},
// The IfNode only compiles into a statement if either of the bodies needs
// to be a statement.
is_statement: function is_statement() {
return this.statement = this.statement || !!(this.comment || this.tags.statement || this.body.is_statement() || (this.else_body && this.else_body.is_statement()));
},
compile_condition: function compile_condition(o) {
var __a, __b, __c, cond;
return ((function() {
__a = []; __b = flatten(this.condition);
for (__c = 0; __c < __b.length; __c++) {
cond = __b[__c];
__a.push(cond.compile(o));
}
return __a;
}).call(this)).join(' || ');
},
compile_node: function compile_node(o) {
return this.is_statement() ? this.compile_statement(o) : this.compile_ternary(o);
},
// Compile the IfNode as a regular if-else statement. Flattened chains
// force sub-else bodies into statement form.
compile_statement: function compile_statement(o) {
var body, child, com_dent, cond_o, else_part, if_dent, if_part, prefix;
child = del(o, 'chain_child');
cond_o = dup(o);
del(cond_o, 'returns');
o.indent = this.idt(1);
o.top = true;
if_dent = child ? '' : this.idt();
com_dent = child ? this.idt() : '';
prefix = this.comment ? this.comment.compile(cond_o) + '\n' + com_dent : '';
body = Expressions.wrap([body]).compile(o);
if_part = prefix + if_dent + 'if (' + compile_condition(cond_o) + ') {\n' + body + '\n' + this.idt() + '}';
if (!(this.else_body)) {
return if_part;
}
else_part = this.is_chain() ? ' else ' + this.else_body.compile(merge(o, {
indent: this.idt(),
chain_child: true
})) : ' else {\n' + Expressions.wrap(this.else_body).compile(o) + '\n' + this.idt() + '}';
return if_part + else_part;
},
// Compile the IfNode into a ternary operator.
compile_ternary: function compile_ternary(o) {
var else_part, if_part;
if_part = this.condition.compile(o) + ' ? ' + this.body.compile(o);
else_part = this.else_body ? this.else_body.compile(o) : 'null';
return if_part + ' : ' + else_part;
}
}));
})();

2
lib/coffee_script/nodes.rb
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@ -1029,7 +1029,7 @@ module CoffeeScript
# Compile the IfNode into a ternary operator.
def compile_ternary(o)
if_part = "#{@condition.compile(o)} ? #{@body.compile(o)}"
else_part = @else_body ? "#{@else_body.compile(o)}" : 'null'
else_part = @else_body ? @else_body.compile(o) : 'null'
"#{if_part} : #{else_part}"
end
end

2
lib/coffee_script/parser.js
View File

@ -462,7 +462,7 @@
statement: true
});
}), o("Comment TERMINATOR When", function() {
return $3.add_comment($1);
return $3.comment = $1;
})
],
// The most basic form of "if".

82
src/nodes.coffee
View File

@ -945,7 +945,87 @@ ForNode: exports.ForNode: inherit Node, {
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.
IfNode: exports.IfNode: inherit Node, {
constructor: (condition, body, else_body, tags) ->
@condition: condition
@body: body and body.unwrap()
@else_body: else_body and else_body.unwrap()
@children: [@condition, @body, @else_body]
@tags: tags or {}
@multiple: true if @condition instanceof Array
@condition: new OpNode('!', new ParentheticalNode(@condition)) if @tags.invert
this
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
# Rewrite a chain of IfNodes with their switch condition for equality.
rewrite_condition: (expression) ->
@condition: if @multiple
new OpNode('is', expression, cond) for cond in @condition
else
new OpNode('is', expression, @condition)
@else_body.rewrite_condition(expression) if @is_chain()
this
# Rewrite a chain of IfNodes to add a default case as the final else.
add_else: (exprs) ->
if @is_chain() then @else_body.add_else(exprs) else @else_body: exprs and exprs.unwrap()
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) ->
child: del o, 'chain_child'
cond_o: dup 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
}

2
src/parser.coffee
View File

@ -405,7 +405,7 @@ grammar: {
When: [
o "LEADING_WHEN SimpleArgs Block", -> new IfNode($2, $3, null, {statement: true})
o "LEADING_WHEN SimpleArgs Block TERMINATOR", -> new IfNode($2, $3, null, {statement: true})
o "Comment TERMINATOR When", -> $3.add_comment($1)
o "Comment TERMINATOR When", -> $3.comment: $1
]
# The most basic form of "if".