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nodes.coffee
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nodes.coffee
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# -*- mode: coffee; tab-width: 2; c-basic-offset: 2; indent-tabs-mode: nil; -*-
# `nodes.coffee` contains all of the node classes for the syntax tree. Most
# nodes are created as the result of actions in the [grammar](grammar.html),
# but some are created by other nodes as a method of code generation. To convert
# the syntax tree into a string of JavaScript code, call `compile()` on the root.
{Scope} = require './scope'
{RESERVED, STRICT_PROSCRIBED} = require './lexer'
tame = require './tame'
# Import the helpers we plan to use.
{compact, flatten, extend, merge, del, starts, ends, last} = require './helpers'
exports.extend = extend # for parser
# Constant functions for nodes that don't need customization.
YES = -> yes
NO = -> no
THIS = -> this
NEGATE = -> @negated = not @negated; this
CALL_CONTINUATION = -> new Call(new Literal tame.const.k, [])
#### Base
# The **Base** is the abstract base class for all nodes in the syntax tree.
# Each subclass implements the `compileNode` method, which performs the
# code generation for that node. To compile a node to JavaScript,
# call `compile` on it, which wraps `compileNode` in some generic extra smarts,
# to know when the generated code needs to be wrapped up in a closure.
# An options hash is passed and cloned throughout, containing information about
# the environment from higher in the tree (such as if a returned value is
# being requested by the surrounding function), information about the current
# scope, and indentation level.
exports.Base = class Base
# Common logic for determining whether to wrap this node in a closure before
# compiling it, or to compile directly. We need to wrap if this node is a
# *statement*, and it's not a *pureStatement*, 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 (because statements know how to
# return results).
compile: (o, lvl) ->
o = extend {}, o
o.level = lvl if lvl
node = @unfoldSoak(o) or this
node.tab = o.indent
if node.hasTaming and not node.gotCpsSplit and node.isStatement(o)
node.compileCps o
else if o.level is LEVEL_TOP or not node.isStatement(o)
node.compileNode o
else
node.compileClosure o
# Statements converted into expressions via closure-wrapping share a scope
# object with their parent closure, to preserve the expected lexical scope.
compileClosure: (o) ->
if @jumps()
throw SyntaxError 'cannot use a pure statement in an expression.'
o.sharedScope = yes
Closure.wrap(this).compileNode o
# Statements that need CPS translation will have to be split into two
# pieces as so
compileCps : (o) ->
@gotCpsSplit = true
node = CpsCascade.wrap(this, @tameContinuationBlock)
ret = node.compile o
ret
# 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,
# by assigning it to a temporary variable. Pass a level to precompile.
cache: (o, level, reused) ->
unless @isComplex()
ref = if level then @compile o, level else this
[ref, ref]
else
ref = new Literal reused or o.scope.freeVariable 'ref'
sub = new Assign ref, this
if level then [sub.compile(o, level), ref.value] else [sub, ref]
# Compile to a source/variable pair suitable for looping.
compileLoopReference: (o, name) ->
src = tmp = @compile o, LEVEL_LIST
unless -Infinity < +src < Infinity or IDENTIFIER.test(src) and o.scope.check(src, yes)
src = "#{ tmp = o.scope.freeVariable name } = #{src}"
[src, tmp]
# Construct a node that returns the current node's result.
# Note that this is overridden for smarter behavior for
# many statement nodes (e.g. If, For)...
makeReturn: (res) ->
me = @unwrapAll()
if res
new Call new Literal("#{res}.push"), [me]
else
new Return me
# Does this node, or any of its children, contain a node of a certain kind?
# Recursively traverses down the *children* of the nodes, yielding to a block
# and returning true when the block finds a match. `contains` does not cross
# scope boundaries.
contains: (pred) ->
contains = no
@traverseChildren no, (node) ->
if pred node
contains = yes
return no
contains
# Is this node of a certain type, or does it contain the type?
containsType: (type) ->
this instanceof type or @contains (node) -> node instanceof type
# Pull out the last non-comment node of a node list.
lastNonComment: (list) ->
i = list.length
return list[i] while i-- when list[i] not instanceof Comment
null
# `toString` representation of the node, for inspecting the parse tree.
# This is what `coffee --nodes` prints out.
toString: (idt = '', name = @constructor.name) ->
extras = ""
if @hasTaming
extras += "T"
if @isCpsTranslated
extras += "C"
if extras.length
extras = " (" + extras + ")"
tree = '\n' + idt + name
tree += '?' if @soak
tree += extras
@eachChild (node) -> tree += node.toString idt + TAB
if @tameContinuationBlock
idt += TAB
tree += '\n' + idt + "Continuation"
tree += @tameContinuationBlock.toString idt + TAB
tree
# Passes each child to a function, breaking when the function returns `false`.
eachChild: (func) ->
return this unless @children
for attr in @children when @[attr]
for child in flatten [@[attr]]
return this if func(child) is false
this
traverseChildren: (crossScope, func) ->
@eachChild (child) ->
return false if func(child) is false
child.traverseChildren crossScope, func
invert: ->
new Op '!', this
unwrapAll: ->
node = this
continue until node is node = node.unwrap()
node
# Don't try this at home with actually human kids
flattenChildren : ->
out = []
for attr in @children when @[attr]
for child in flatten [@[attr]]
out.push (child)
out
# Walk the AST looking for taming. Mark a node as 'hasTaming'
# if any of its children are tamed, but don't cross scope boundary
# when considering the children
walkTaming : ->
@hasTaming = false
for child in @flattenChildren()
@hasTaming = true if child.walkTaming()
return @hasTaming
# Mark each node as weather or not it needs CPS translation,
# to be called after walkTaming. All children of a node that
# hasTaming needs to be CPS-translated, of course, stopping on
# function boundaries.
floodCpsTranslation : ->
@isCpsTranslated = true
@traverseChildren false, (x) -> x.floodCpsTranslation()
# Default implementations of the common node properties and methods. Nodes
# will override these with custom logic, if needed.
children: []
# A potential for a nested tame continuation here
tameContinuationBlock : null
# A generic tame AST rotation is just to push down to its children
cpsRotate: ->
for child in @flattenChildren()
child.cpsRotate()
this
tameNestContinuationBlock : (b) ->
@tameContinuationBlock = b
callContinuation : ->
isStatement : NO
jumps : NO
isComplex : YES
isChainable : NO
isAssignable : NO
isControlBreak : NO
isTamedFunc : NO
hasTaming : false
isCpsTranslated : false
gotCpsSplit : false
unwrap : THIS
unfoldSoak : NO
# Is this node used to assign a certain variable?
assigns: NO
#### Block
# The block is the list of expressions that forms the body of an
# indented block of code -- the implementation of a function, a clause in an
# `if`, `switch`, or `try`, and so on...
exports.Block = class Block extends Base
constructor: (nodes) ->
@expressions = compact flatten nodes or []
children: ['expressions']
# Tack an expression on to the end of this expression list.
push: (node) ->
@expressions.push node
this
# Remove and return the last expression of this expression list.
pop: ->
@expressions.pop()
# Add an expression at the beginning of this expression list.
unshift: (node) ->
@expressions.unshift node
this
# If this Block consists of just a single node, unwrap it by pulling
# it back out.
unwrap: ->
if @expressions.length is 1 then @expressions[0] else this
# Is this an empty block of code?
isEmpty: ->
not @expressions.length
isStatement: (o) ->
for exp in @expressions when exp.isStatement o
return yes
no
jumps: (o) ->
for exp in @expressions
return exp if exp.jumps o
# A Block node does not return its entire body, rather it
# ensures that the final expression is returned.
makeReturn: (res) ->
len = @expressions.length
while len--
expr = @expressions[len]
if expr not instanceof Comment
@expressions[len] = expr.makeReturn res
@expressions.splice(len, 1) if expr instanceof Return and not expr.expression
break
this
# A **Block** is the only node that can serve as the root.
compile: (o = {}, level) ->
if o.scope then super o, level else @compileRoot o
# Compile all expressions within the **Block** body. If we need to
# return the result, and it's an expression, simply return it. If it's a
# statement, ask the statement to do so.
compileNode: (o) ->
@tab = o.indent
top = o.level is LEVEL_TOP
codes = []
for node in @expressions
node = node.unwrapAll()
node = (node.unfoldSoak(o) or node)
if node instanceof Block
# This is a nested block. We don't do anything special here like enclose
# it in a new scope; we just compile the statements in this block along with
# our own
codes.push node.compileNode o
else if top
node.front = true
code = node.compile o
unless node.isStatement o
code = "#{@tab}#{code};"
code = "#{code}\n" if node instanceof Literal
codes.push code
else
codes.push node.compile o, LEVEL_LIST
if top
if @spaced
return "\n#{codes.join '\n\n'}\n"
else
return codes.join '\n'
code = codes.join(', ') or 'void 0'
if codes.length > 1 and o.level >= LEVEL_LIST then "(#{code})" else code
# If we happen to be the top-level **Block**, wrap everything in
# a safety closure, unless requested not to.
# It would be better not to generate them in the first place, but for now,
# clean up obvious double-parentheses.
compileRoot: (o) ->
o.indent = if o.bare then '' else TAB
o.scope = new Scope null, this, null
o.level = LEVEL_TOP
@spaced = yes
prelude = ""
unless o.bare
preludeExps = for exp, i in @expressions
break unless exp.unwrap() instanceof Comment
exp
rest = @expressions[preludeExps.length...]
@expressions = preludeExps
prelude = "#{@compileNode merge(o, indent: '')}\n" if preludeExps.length
@expressions = rest
code = @compileWithDeclarations o
return code if o.bare
"#{prelude}(function() {\n#{code}\n}).call(this);\n"
# Compile the expressions body for the contents of a function, with
# declarations of all inner variables pushed up to the top.
compileWithDeclarations: (o) ->
code = post = ''
for exp, i in @expressions
exp = exp.unwrap()
break unless exp instanceof Comment or exp instanceof Literal
o = merge(o, level: LEVEL_TOP)
if i
rest = @expressions.splice i, 9e9
[spaced, @spaced] = [@spaced, no]
[code , @spaced] = [(@compileNode o), spaced]
@expressions = rest
post = @compileNode o
{scope} = o
if scope.expressions is this
declars = o.scope.hasDeclarations()
assigns = scope.hasAssignments
if declars or assigns
code += '\n' if i
code += "#{@tab}var "
if declars
code += scope.declaredVariables().join ', '
if assigns
code += ",\n#{@tab + TAB}" if declars
code += scope.assignedVariables().join ",\n#{@tab + TAB}"
code += ';\n'
code + post
cpsRotate : ->
pivot = null
# If this Block has taming, then we go ahead and look for a pivot
if @hasTaming
i = 0
for e in @expressions
if e.hasTaming
pivot = e
break
i++
# We find a pivot if this node hasTaming, and it's not an Await
# itself
if pivot
# flood that all children of the pivot need to be CPS-Translated
pivot.floodCpsTranslation()
# include the pivot in this slice!
rest = @expressions.slice(i+1)
@expressions = @expressions.slice(0,i+1)
if rest.length
child = new Block rest
pivot.tameNestContinuationBlock child
pivot.callContinuation()
# After we have pivoted this guy, we still need to walk all of the
# expressions, because maybe the expressions that we left still have
# embedded functions that need the rotation run on them. Thus,
# hasTaming will be false, but children might have blocks that still
# need to be tamed
super()
# return this for chaining
this
addCpsChain : ->
@expressions.push(new Call(new Literal tame.const.k, []))
# Wrap up the given nodes as a **Block**, unless it already happens
# to be one.
@wrap: (nodes) ->
return nodes[0] if nodes.length is 1 and nodes[0] instanceof Block
new Block nodes
# Perform all steps of the Tame transform
tameTransform : ->
@walkTaming()
@cpsRotate()
#### Literal
# Literals are static values that can be passed through directly into
# JavaScript without translation, such as: strings, numbers,
# `true`, `false`, `null`...
exports.Literal = class Literal extends Base
constructor: (@value) ->
makeReturn: ->
if @isStatement() then this else super
isAssignable: ->
IDENTIFIER.test @value
isStatement: ->
@value in ['break', 'continue', 'debugger']
isComplex: NO
assigns: (name) ->
name is @value
jumps: (o) ->
return this if @value is 'break' and not (o?.loop or o?.block)
return this if @value is 'continue' and not o?.loop
compileNode: (o) ->
code = if @isUndefined
if o.level >= LEVEL_ACCESS then '(void 0)' else 'void 0'
else if @value is 'this'
if o.scope.method?.bound then o.scope.method.context else @value
else if @value.reserved
"\"#{@value}\""
else
@value
if @isStatement() then "#{@tab}#{code};" else code
toString: ->
' "' + @value + '"'
#### Return
# A `return` is a *pureStatement* -- wrapping it in a closure wouldn't
# make sense.
exports.Return = class Return extends Base
constructor: (expr) ->
@expression = expr if expr and not expr.unwrap().isUndefined
children: ['expression']
isStatement: YES
makeReturn: THIS
jumps: THIS
compile: (o, level) ->
expr = @expression?.makeReturn()
if expr and expr not instanceof Return then expr.compile o, level else super o, level
compileNode: (o) ->
@tab + "return#{[" #{@expression.compile o, LEVEL_PAREN}" if @expression]};"
#### Value
# A value, variable or literal or parenthesized, indexed or dotted into,
# or vanilla.
exports.Value = class Value extends Base
constructor: (base, props, tag) ->
return base if not props and base instanceof Value
@base = base
@properties = props or []
@[tag] = true if tag
return this
children: ['base', 'properties']
# Add a property (or *properties* ) `Access` to the list.
add: (props) ->
@properties = @properties.concat props
this
hasProperties: ->
!!@properties.length
# Some boolean checks for the benefit of other nodes.
isArray : -> not @properties.length and @base instanceof Arr
isComplex : -> @hasProperties() or @base.isComplex()
isAssignable : -> @hasProperties() or @base.isAssignable()
isSimpleNumber : -> @base instanceof Literal and SIMPLENUM.test @base.value
isString : -> @base instanceof Literal and IS_STRING.test @base.value
isAtomic : ->
for node in @properties.concat @base
return no if node.soak or node instanceof Call
yes
isStatement : (o) -> not @properties.length and @base.isStatement o
assigns : (name) -> not @properties.length and @base.assigns name
jumps : (o) -> not @properties.length and @base.jumps o
isObject: (onlyGenerated) ->
return no if @properties.length
(@base instanceof Obj) and (not onlyGenerated or @base.generated)
isSplice: ->
last(@properties) instanceof Slice
# The value can be unwrapped as its inner node, if there are no attached
# properties.
unwrap: ->
if @properties.length then this else @base
# A reference has base part (`this` value) and name part.
# We cache them separately for compiling complex expressions.
# `a()[b()] ?= c` -> `(_base = a())[_name = b()] ? _base[_name] = c`
cacheReference: (o) ->
name = last @properties
if @properties.length < 2 and not @base.isComplex() and not name?.isComplex()
return [this, this] # `a` `a.b`
base = new Value @base, @properties[...-1]
if base.isComplex() # `a().b`
bref = new Literal o.scope.freeVariable 'base'
base = new Value new Parens new Assign bref, base
return [base, bref] unless name # `a()`
if name.isComplex() # `a[b()]`
nref = new Literal o.scope.freeVariable 'name'
name = new Index new Assign nref, name.index
nref = new Index nref
[base.add(name), new Value(bref or base.base, [nref or name])]
# We compile a value to JavaScript by compiling and joining each property.
# Things get much more interesting if the chain of properties has *soak*
# operators `?.` interspersed. Then we have to take care not to accidentally
# evaluate anything twice when building the soak chain.
compileNode: (o) ->
@base.front = @front
props = @properties
code = @base.compile o, if props.length then LEVEL_ACCESS else null
code = "#{code}." if (@base instanceof Parens or props.length) and SIMPLENUM.test code
code += prop.compile o for prop in props
code
# Unfold a soak into an `If`: `a?.b` -> `a.b if a?`
unfoldSoak: (o) ->
return @unfoldedSoak if @unfoldedSoak?
result = do =>
if ifn = @base.unfoldSoak o
Array::push.apply ifn.body.properties, @properties
return ifn
for prop, i in @properties when prop.soak
prop.soak = off
fst = new Value @base, @properties[...i]
snd = new Value @base, @properties[i..]
if fst.isComplex()
ref = new Literal o.scope.freeVariable 'ref'
fst = new Parens new Assign ref, fst
snd.base = ref
return new If new Existence(fst), snd, soak: on
null
@unfoldedSoak = result or no
#### Comment
# CoffeeScript passes through block comments as JavaScript block comments
# at the same position.
exports.Comment = class Comment extends Base
constructor: (@comment) ->
isStatement: YES
makeReturn: THIS
compileNode: (o, level) ->
code = '/*' + multident(@comment, @tab) + "\n#{@tab}*/\n"
code = o.indent + code if (level or o.level) is LEVEL_TOP
code
#### Call
# Node for a function invocation. Takes care of converting `super()` calls into
# calls against the prototype's function of the same name.
exports.Call = class Call extends Base
constructor: (variable, @args = [], @soak) ->
@isNew = false
@isSuper = variable is 'super'
@variable = if @isSuper then null else variable
children: ['variable', 'args']
# Tag this invocation as creating a new instance.
newInstance: ->
base = @variable?.base or @variable
if base instanceof Call and not base.isNew
base.newInstance()
else
@isNew = true
this
# Grab the reference to the superclass's implementation of the current
# method.
superReference: (o) ->
{method} = o.scope
throw SyntaxError 'cannot call super outside of a function.' unless method
{name} = method
throw SyntaxError 'cannot call super on an anonymous function.' unless name?
if method.klass
accesses = [new Access(new Literal '__super__')]
accesses.push new Access new Literal 'constructor' if method.static
accesses.push new Access new Literal name
(new Value (new Literal method.klass), accesses).compile o
else
"#{name}.__super__.constructor"
# Soaked chained invocations unfold into if/else ternary structures.
unfoldSoak: (o) ->
if @soak
if @variable
return ifn if ifn = unfoldSoak o, this, 'variable'
[left, rite] = new Value(@variable).cacheReference o
else
left = new Literal @superReference o
rite = new Value left
rite = new Call rite, @args
rite.isNew = @isNew
left = new Literal "typeof #{ left.compile o } === \"function\""
return new If left, new Value(rite), soak: yes
call = this
list = []
loop
if call.variable instanceof Call
list.push call
call = call.variable
continue
break unless call.variable instanceof Value
list.push call
break unless (call = call.variable.base) instanceof Call
for call in list.reverse()
if ifn
if call.variable instanceof Call
call.variable = ifn
else
call.variable.base = ifn
ifn = unfoldSoak o, call, 'variable'
ifn
# Walk through the objects in the arguments, moving over simple values.
# This allows syntax like `call a: b, c` into `call({a: b}, c);`
filterImplicitObjects: (list) ->
nodes = []
for node in list
unless node.isObject?() and node.base.generated
nodes.push node
continue
obj = null
for prop in node.base.properties
if prop instanceof Assign or prop instanceof Comment
nodes.push obj = new Obj properties = [], true if not obj
properties.push prop
else
nodes.push prop
obj = null
nodes
# Compile a vanilla function call.
compileNode: (o) ->
@variable?.front = @front
if code = Splat.compileSplattedArray o, @args, true
return @compileSplat o, code
args = @filterImplicitObjects @args
args = (arg.compile o, LEVEL_LIST for arg in args).join ', '
if @isSuper
@superReference(o) + ".call(this#{ args and ', ' + args })"
else
(if @isNew then 'new ' else '') + @variable.compile(o, LEVEL_ACCESS) + "(#{args})"
# `super()` is converted into a call against the superclass's implementation
# of the current function.
compileSuper: (args, o) ->
"#{@superReference(o)}.call(this#{ if args.length then ', ' else '' }#{args})"
# If you call a function with a splat, it's converted into a JavaScript
# `.apply()` call to allow an array of arguments to be passed.
# If it's a constructor, then things get real tricky. We have to inject an
# inner constructor in order to be able to pass the varargs.
compileSplat: (o, splatArgs) ->
return "#{ @superReference o }.apply(this, #{splatArgs})" if @isSuper
if @isNew
idt = @tab + TAB
return """
(function(func, args, ctor) {
#{idt}ctor.prototype = func.prototype;
#{idt}var child = new ctor, result = func.apply(child, args);
#{idt}return typeof result === "object" ? result : child;
#{@tab}})(#{ @variable.compile o, LEVEL_LIST }, #{splatArgs}, function() {})
"""
base = new Value @variable
if (name = base.properties.pop()) and base.isComplex()
ref = o.scope.freeVariable 'ref'
fun = "(#{ref} = #{ base.compile o, LEVEL_LIST })#{ name.compile o }"
else
fun = base.compile o, LEVEL_ACCESS
fun = "(#{fun})" if SIMPLENUM.test fun
if name
ref = fun
fun += name.compile o
else
ref = 'null'
"#{fun}.apply(#{ref}, #{splatArgs})"
#### Extends
# Node to extend an object's prototype with an ancestor object.
# After `goog.inherits` from the
# [Closure Library](http://closure-library.googlecode.com/svn/docs/closureGoogBase.js.html).
exports.Extends = class Extends extends Base
constructor: (@child, @parent) ->
children: ['child', 'parent']
# Hooks one constructor into another's prototype chain.
compile: (o) ->
new Call(new Value(new Literal utility 'extends'), [@child, @parent]).compile o
#### Access
# A `.` access into a property of a value, or the `::` shorthand for
# an access into the object's prototype.
exports.Access = class Access extends Base
constructor: (@name, tag) ->
@name.asKey = yes
@soak = tag is 'soak'
children: ['name']
compile: (o) ->
name = @name.compile o
if IDENTIFIER.test name then ".#{name}" else "[#{name}]"
isComplex: NO
#### Index
# A `[ ... ]` indexed access into an array or object.
exports.Index = class Index extends Base
constructor: (@index) ->
children: ['index']
compile: (o) ->
"[#{ @index.compile o, LEVEL_PAREN }]"
isComplex: ->
@index.isComplex()
#### Range
# A range literal. Ranges can be used to extract portions (slices) of arrays,
# to specify a range for comprehensions, or as a value, to be expanded into the
# corresponding array of integers at runtime.
exports.Range = class Range extends Base
children: ['from', 'to']
constructor: (@from, @to, tag) ->
@exclusive = tag is 'exclusive'
@equals = if @exclusive then '' else '='
# Compiles the range's source variables -- where it starts and where it ends.
# But only if they need to be cached to avoid double evaluation.
compileVariables: (o) ->
o = merge o, top: true
[@fromC, @fromVar] = @from.cache o, LEVEL_LIST
[@toC, @toVar] = @to.cache o, LEVEL_LIST
[@step, @stepVar] = step.cache o, LEVEL_LIST if step = del o, 'step'
[@fromNum, @toNum] = [@fromVar.match(SIMPLENUM), @toVar.match(SIMPLENUM)]
@stepNum = @stepVar.match(SIMPLENUM) if @stepVar
# When compiled normally, the range returns the contents of the *for loop*
# needed to iterate over the values in the range. Used by comprehensions.
compileNode: (o) ->
@compileVariables o unless @fromVar
return @compileArray(o) unless o.index
# Set up endpoints.
known = @fromNum and @toNum
idx = del o, 'index'
idxName = del o, 'name'
namedIndex = idxName and idxName isnt idx
varPart = "#{idx} = #{@fromC}"
varPart += ", #{@toC}" if @toC isnt @toVar
varPart += ", #{@step}" if @step isnt @stepVar
[lt, gt] = ["#{idx} <#{@equals}", "#{idx} >#{@equals}"]
# Generate the condition.
condPart = if @stepNum
if +@stepNum > 0 then "#{lt} #{@toVar}" else "#{gt} #{@toVar}"
else if known
[from, to] = [+@fromNum, +@toNum]
if from <= to then "#{lt} #{to}" else "#{gt} #{to}"
else
cond = "#{@fromVar} <= #{@toVar}"
"#{cond} ? #{lt} #{@toVar} : #{gt} #{@toVar}"
# Generate the step.
stepPart = if @stepVar
"#{idx} += #{@stepVar}"
else if known
if namedIndex
if from <= to then "++#{idx}" else "--#{idx}"
else
if from <= to then "#{idx}++" else "#{idx}--"
else
if namedIndex
"#{cond} ? ++#{idx} : --#{idx}"
else
"#{cond} ? #{idx}++ : #{idx}--"
varPart = "#{idxName} = #{varPart}" if namedIndex
stepPart = "#{idxName} = #{stepPart}" if namedIndex
# The final loop body.
"#{varPart}; #{condPart}; #{stepPart}"
# When used as a value, expand the range into the equivalent array.
compileArray: (o) ->
if @fromNum and @toNum and Math.abs(@fromNum - @toNum) <= 20
range = [+@fromNum..+@toNum]
range.pop() if @exclusive
return "[#{ range.join(', ') }]"
idt = @tab + TAB
i = o.scope.freeVariable 'i'
result = o.scope.freeVariable 'results'
pre = "\n#{idt}#{result} = [];"
if @fromNum and @toNum
o.index = i
body = @compileNode o
else
vars = "#{i} = #{@fromC}" + if @toC isnt @toVar then ", #{@toC}" else ''
cond = "#{@fromVar} <= #{@toVar}"
body = "var #{vars}; #{cond} ? #{i} <#{@equals} #{@toVar} : #{i} >#{@equals} #{@toVar}; #{cond} ? #{i}++ : #{i}--"
post = "{ #{result}.push(#{i}); }\n#{idt}return #{result};\n#{o.indent}"
hasArgs = (node) -> node?.contains (n) -> n instanceof Literal and n.value is 'arguments' and not n.asKey
args = ', arguments' if hasArgs(@from) or hasArgs(@to)
"(function() {#{pre}\n#{idt}for (#{body})#{post}}).apply(this#{args ? ''})"
#### Slice
# An array slice literal. Unlike JavaScript's `Array#slice`, the second parameter
# specifies the index of the end of the slice, just as the first parameter
# is the index of the beginning.
exports.Slice = class Slice extends Base
children: ['range']
constructor: (@range) ->
super()
# We have to be careful when trying to slice through the end of the array,
# `9e9` is used because not all implementations respect `undefined` or `1/0`.
# `9e9` should be safe because `9e9` > `2**32`, the max array length.
compileNode: (o) ->
{to, from} = @range
fromStr = from and from.compile(o, LEVEL_PAREN) or '0'
compiled = to and to.compile o, LEVEL_PAREN
if to and not (not @range.exclusive and +compiled is -1)
toStr = ', ' + if @range.exclusive
compiled
else if SIMPLENUM.test compiled
"#{+compiled + 1}"
else
compiled = to.compile o, LEVEL_ACCESS
"#{compiled} + 1 || 9e9"
".slice(#{ fromStr }#{ toStr or '' })"
#### Obj
# An object literal, nothing fancy.
exports.Obj = class Obj extends Base
constructor: (props, @generated = false) ->
@objects = @properties = props or []
children: ['properties']
compileNode: (o) ->
props = @properties
propNames = []
for prop in @properties
prop = prop.variable if prop.isComplex()
if prop?
propName = prop.unwrapAll().value.toString()
if propName in propNames
throw SyntaxError "multiple object literal properties named \"#{propName}\""
propNames.push propName
return (if @front then '({})' else '{}') unless props.length
if @generated
for node in props when node instanceof Value
throw new Error 'cannot have an implicit value in an implicit object'
idt = o.indent += TAB
lastNoncom = @lastNonComment @properties
props = for prop, i in props
join = if i is props.length - 1
''
else if prop is lastNoncom or prop instanceof Comment
'\n'
else
',\n'
indent = if prop instanceof Comment then '' else idt
if prop instanceof Value and prop.this
prop = new Assign prop.properties[0].name, prop, 'object'
if prop not instanceof Comment
if prop not instanceof Assign
prop = new Assign prop, prop, 'object'
(prop.variable.base or prop.variable).asKey = yes
indent + prop.compile(o, LEVEL_TOP) + join
props = props.join ''
obj = "{#{ props and '\n' + props + '\n' + @tab }}"
if @front then "(#{obj})" else obj
assigns: (name) ->
for prop in @properties when prop.assigns name then return yes
no
#### Arr
# An array literal.
exports.Arr = class Arr extends Base
constructor: (objs) ->
@objects = objs or []
children: ['objects']
filterImplicitObjects: Call::filterImplicitObjects
compileNode: (o) ->
return '[]' unless @objects.length
o.indent += TAB
objs = @filterImplicitObjects @objects
return code if code = Splat.compileSplattedArray o, objs
code = (obj.compile o, LEVEL_LIST for obj in objs).join ', '
if code.indexOf('\n') >= 0
"[\n#{o.indent}#{code}\n#{@tab}]"
else
"[#{code}]"
assigns: (name) ->
for obj in @objects when obj.assigns name then return yes
no
#### Class
# The CoffeeScript class definition.
# Initialize a **Class** with its name, an optional superclass, and a
# list of prototype property assignments.
exports.Class = class Class extends Base
constructor: (@variable, @parent, @body = new Block) ->
@boundFuncs = []
@body.classBody = yes
children: ['variable', 'parent', 'body']
# Figure out the appropriate name for the constructor function of this class.
determineName: ->
return null unless @variable
decl = if tail = last @variable.properties
tail instanceof Access and tail.name.value
else
@variable.base.value
if decl in STRICT_PROSCRIBED
throw SyntaxError "variable name may not be #{decl}"
decl and= IDENTIFIER.test(decl) and decl
# For all `this`-references and bound functions in the class definition,
# `this` is the Class being constructed.
setContext: (name) ->
@body.traverseChildren false, (node) ->
return false if node.classBody
if node instanceof Literal and node.value is 'this'
node.value = name
else if node instanceof Code
node.klass = name
node.context = name if node.bound
# Ensure that all functions bound to the instance are proxied in the
# constructor.
addBoundFunctions: (o) ->
if @boundFuncs.length
for bvar in @boundFuncs
lhs = (new Value (new Literal "this"), [new Access bvar]).compile o
@ctor.body.unshift new Literal "#{lhs} = #{utility 'bind'}(#{lhs}, this)"