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<h1>nodes.coffee</h1>
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<p><code>nodes.coffee</code> contains all of the node classes for the syntax tree. Most
nodes are created as the result of actions in the <a href="grammar.html">grammar</a>,
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 <code>compile()</code> on the root.</p>
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<div class="content"><div class='highlight'><pre>
Error.stackTraceLimit = Infinity
{Scope} = <span class="hljs-built_in">require</span> <span class="hljs-string">'./scope'</span>
{RESERVED, STRICT_PROSCRIBED} = <span class="hljs-built_in">require</span> <span class="hljs-string">'./lexer'</span></pre></div></div>
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<p>Import the helpers we plan to use.</p>
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<div class="content"><div class='highlight'><pre>{compact, flatten, extend, merge, del, starts, ends, some,
addLocationDataFn, locationDataToString, throwSyntaxError} = <span class="hljs-built_in">require</span> <span class="hljs-string">'./helpers'</span></pre></div></div>
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<p>Functions required by parser</p>
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<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.extend = extend
<span class="hljs-built_in">exports</span>.addLocationDataFn = addLocationDataFn</pre></div></div>
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<p>Constant functions for nodes that don’t need customization.</p>
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<div class="content"><div class='highlight'><pre><span class="hljs-function"><span class="hljs-title">YES</span> = -></span> <span class="hljs-literal">yes</span>
<span class="hljs-function"><span class="hljs-title">NO</span> = -></span> <span class="hljs-literal">no</span>
<span class="hljs-function"><span class="hljs-title">THIS</span> = -></span> <span class="hljs-keyword">this</span>
<span class="hljs-function"><span class="hljs-title">NEGATE</span> = -></span> <span class="hljs-property">@negated</span> = <span class="hljs-keyword">not</span> <span class="hljs-property">@negated</span>; <span class="hljs-keyword">this</span></pre></div></div>
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<h3 id="codefragment">CodeFragment</h3>
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<p>The various nodes defined below all compile to a collection of <strong>CodeFragment</strong> objects.
A CodeFragments is a block of generated code, and the location in the source file where the code
came from. CodeFragments can be assembled together into working code just by catting together
all the CodeFragments’ <code>code</code> snippets, in order.</p>
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<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.CodeFragment = <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">CodeFragment</span></span>
<span class="hljs-attribute">constructor</span>: <span class="hljs-function"><span class="hljs-params">(parent, code)</span> -></span>
<span class="hljs-property">@code</span> = <span class="hljs-string">"<span class="hljs-subst">#{code}</span>"</span>
<span class="hljs-property">@locationData</span> = parent?.locationData
<span class="hljs-property">@type</span> = parent?.constructor?.name <span class="hljs-keyword">or</span> <span class="hljs-string">'unknown'</span>
<span class="hljs-attribute">toString</span>:<span class="hljs-function"> -></span>
<span class="hljs-string">"<span class="hljs-subst">#{<span class="hljs-property">@code</span>}</span><span class="hljs-subst">#{<span class="hljs-keyword">if</span> <span class="hljs-property">@locationData</span> <span class="hljs-keyword">then</span> <span class="hljs-string">": "</span> + locationDataToString(<span class="hljs-property">@locationData</span>) <span class="hljs-keyword">else</span> <span class="hljs-string">''</span>}</span>"</span></pre></div></div>
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<p>Convert an array of CodeFragments into a string.</p>
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<div class="content"><div class='highlight'><pre><span class="hljs-function"><span class="hljs-title">fragmentsToText</span> = <span class="hljs-params">(fragments)</span> -></span>
(fragment.code <span class="hljs-keyword">for</span> fragment <span class="hljs-keyword">in</span> fragments).join(<span class="hljs-string">''</span>)</pre></div></div>
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<h3 id="base">Base</h3>
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<p>The <strong>Base</strong> is the abstract base class for all nodes in the syntax tree.
Each subclass implements the <code>compileNode</code> method, which performs the
code generation for that node. To compile a node to JavaScript,
call <code>compile</code> on it, which wraps <code>compileNode</code> 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.</p>
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<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.Base = <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">Base</span></span>
<span class="hljs-attribute">compile</span>: <span class="hljs-function"><span class="hljs-params">(o, lvl)</span> -></span>
fragmentsToText <span class="hljs-property">@compileToFragments</span> o, lvl</pre></div></div>
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<p>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
<em>statement</em>, and it’s not a <em>pureStatement</em>, 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).</p>
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<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">compileToFragments</span>: <span class="hljs-function"><span class="hljs-params">(o, lvl)</span> -></span>
o = extend {}, o
o.level = lvl <span class="hljs-keyword">if</span> lvl
node = <span class="hljs-property">@unfoldSoak</span>(o) <span class="hljs-keyword">or</span> <span class="hljs-keyword">this</span>
node.tab = o.indent
<span class="hljs-keyword">if</span> o.level <span class="hljs-keyword">is</span> LEVEL_TOP <span class="hljs-keyword">or</span> <span class="hljs-keyword">not</span> node.isStatement(o)
node.compileNode o
<span class="hljs-keyword">else</span>
node.compileClosure o</pre></div></div>
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<p>Statements converted into expressions via closure-wrapping share a scope
object with their parent closure, to preserve the expected lexical scope.</p>
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<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">compileClosure</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
<span class="hljs-keyword">if</span> jumpNode = <span class="hljs-property">@jumps</span>()
jumpNode.error <span class="hljs-string">'cannot use a pure statement in an expression'</span>
o.sharedScope = <span class="hljs-literal">yes</span>
func = <span class="hljs-keyword">new</span> Code [], Block.wrap [<span class="hljs-keyword">this</span>]
args = []
<span class="hljs-keyword">if</span> (argumentsNode = <span class="hljs-property">@contains</span> isLiteralArguments) <span class="hljs-keyword">or</span> <span class="hljs-property">@contains</span> isLiteralThis
args = [<span class="hljs-keyword">new</span> Literal <span class="hljs-string">'this'</span>]
<span class="hljs-keyword">if</span> argumentsNode
meth = <span class="hljs-string">'apply'</span>
args.push <span class="hljs-keyword">new</span> Literal <span class="hljs-string">'arguments'</span>
<span class="hljs-keyword">else</span>
meth = <span class="hljs-string">'call'</span>
func = <span class="hljs-keyword">new</span> Value func, [<span class="hljs-keyword">new</span> Access <span class="hljs-keyword">new</span> Literal meth]
parts = (<span class="hljs-keyword">new</span> Call func, args).compileNode o
<span class="hljs-keyword">if</span> func.isGenerator <span class="hljs-keyword">or</span> func.base?.isGenerator
parts.unshift <span class="hljs-property">@makeCode</span> <span class="hljs-string">"(yield* "</span>
parts.push <span class="hljs-property">@makeCode</span> <span class="hljs-string">")"</span>
parts</pre></div></div>
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<p>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.</p>
<p>If <code>level</code> is passed, then returns <code>[val, ref]</code>, where <code>val</code> is the compiled value, and <code>ref</code>
is the compiled reference. If <code>level</code> is not passed, this returns <code>[val, ref]</code> where
the two values are raw nodes which have not been compiled.</p>
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<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">cache</span>: <span class="hljs-function"><span class="hljs-params">(o, level, isComplex)</span> -></span>
complex = <span class="hljs-keyword">if</span> isComplex? <span class="hljs-keyword">then</span> isComplex <span class="hljs-keyword">this</span> <span class="hljs-keyword">else</span> <span class="hljs-property">@isComplex</span>()
<span class="hljs-keyword">if</span> complex
ref = <span class="hljs-keyword">new</span> Literal o.scope.freeVariable <span class="hljs-string">'ref'</span>
sub = <span class="hljs-keyword">new</span> Assign ref, <span class="hljs-keyword">this</span>
<span class="hljs-keyword">if</span> level <span class="hljs-keyword">then</span> [sub.compileToFragments(o, level), [<span class="hljs-property">@makeCode</span>(ref.value)]] <span class="hljs-keyword">else</span> [sub, ref]
<span class="hljs-keyword">else</span>
ref = <span class="hljs-keyword">if</span> level <span class="hljs-keyword">then</span> <span class="hljs-property">@compileToFragments</span> o, level <span class="hljs-keyword">else</span> <span class="hljs-keyword">this</span>
[ref, ref]
<span class="hljs-attribute">cacheToCodeFragments</span>: <span class="hljs-function"><span class="hljs-params">(cacheValues)</span> -></span>
[fragmentsToText(cacheValues[<span class="hljs-number">0</span>]), fragmentsToText(cacheValues[<span class="hljs-number">1</span>])]</pre></div></div>
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<p>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)…</p>
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<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">makeReturn</span>: <span class="hljs-function"><span class="hljs-params">(res)</span> -></span>
me = <span class="hljs-property">@unwrapAll</span>()
<span class="hljs-keyword">if</span> res
<span class="hljs-keyword">new</span> Call <span class="hljs-keyword">new</span> Literal(<span class="hljs-string">"<span class="hljs-subst">#{res}</span>.push"</span>), [me]
<span class="hljs-keyword">else</span>
<span class="hljs-keyword">new</span> Return me</pre></div></div>
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<p>Does this node, or any of its children, contain a node of a certain kind?
Recursively traverses down the <em>children</em> nodes and returns the first one
that verifies <code>pred</code>. Otherwise return undefined. <code>contains</code> does not cross
scope boundaries.</p>
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<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">contains</span>: <span class="hljs-function"><span class="hljs-params">(pred)</span> -></span>
node = <span class="hljs-literal">undefined</span>
<span class="hljs-property">@traverseChildren</span> <span class="hljs-literal">no</span>, <span class="hljs-function"><span class="hljs-params">(n)</span> -></span>
<span class="hljs-keyword">if</span> pred n
node = n
<span class="hljs-keyword">return</span> <span class="hljs-literal">no</span>
node</pre></div></div>
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<p>Pull out the last non-comment node of a node list.</p>
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<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">lastNonComment</span>: <span class="hljs-function"><span class="hljs-params">(list)</span> -></span>
i = list.length
<span class="hljs-keyword">return</span> list[i] <span class="hljs-keyword">while</span> i-- <span class="hljs-keyword">when</span> list[i] <span class="hljs-keyword">not</span> <span class="hljs-keyword">instanceof</span> Comment
<span class="hljs-literal">null</span></pre></div></div>
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<p><code>toString</code> representation of the node, for inspecting the parse tree.
This is what <code>coffee --nodes</code> prints out.</p>
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<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">toString</span>: <span class="hljs-function"><span class="hljs-params">(idt = <span class="hljs-string">''</span>, name = <span class="hljs-property">@constructor</span>.name)</span> -></span>
tree = <span class="hljs-string">'\n'</span> + idt + name
tree += <span class="hljs-string">'?'</span> <span class="hljs-keyword">if</span> <span class="hljs-property">@soak</span>
<span class="hljs-property">@eachChild</span> <span class="hljs-function"><span class="hljs-params">(node)</span> -></span> tree += node.toString idt + TAB
tree</pre></div></div>
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<p>Passes each child to a function, breaking when the function returns <code>false</code>.</p>
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<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">eachChild</span>: <span class="hljs-function"><span class="hljs-params">(func)</span> -></span>
<span class="hljs-keyword">return</span> <span class="hljs-keyword">this</span> <span class="hljs-keyword">unless</span> <span class="hljs-property">@children</span>
<span class="hljs-keyword">for</span> attr <span class="hljs-keyword">in</span> <span class="hljs-property">@children</span> <span class="hljs-keyword">when</span> @[attr]
<span class="hljs-keyword">for</span> child <span class="hljs-keyword">in</span> flatten [@[attr]]
<span class="hljs-keyword">return</span> <span class="hljs-keyword">this</span> <span class="hljs-keyword">if</span> func(child) <span class="hljs-keyword">is</span> <span class="hljs-literal">false</span>
<span class="hljs-keyword">this</span>
<span class="hljs-attribute">traverseChildren</span>: <span class="hljs-function"><span class="hljs-params">(crossScope, func)</span> -></span>
<span class="hljs-property">@eachChild</span> <span class="hljs-function"><span class="hljs-params">(child)</span> -></span>
recur = func(child)
child.traverseChildren(crossScope, func) <span class="hljs-keyword">unless</span> recur <span class="hljs-keyword">is</span> <span class="hljs-literal">no</span>
<span class="hljs-attribute">invert</span>:<span class="hljs-function"> -></span>
<span class="hljs-keyword">new</span> Op <span class="hljs-string">'!'</span>, <span class="hljs-keyword">this</span>
<span class="hljs-attribute">unwrapAll</span>:<span class="hljs-function"> -></span>
node = <span class="hljs-keyword">this</span>
<span class="hljs-keyword">continue</span> <span class="hljs-keyword">until</span> node <span class="hljs-keyword">is</span> node = node.unwrap()
node</pre></div></div>
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<p>Default implementations of the common node properties and methods. Nodes
will override these with custom logic, if needed.</p>
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<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">children</span>: []
isStatement : NO
jumps : NO
isComplex : YES
isChainable : NO
isAssignable : NO
unwrap : THIS
unfoldSoak : NO</pre></div></div>
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<p>Is this node used to assign a certain variable?</p>
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<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">assigns</span>: NO</pre></div></div>
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<p>For this node and all descendents, set the location data to <code>locationData</code>
if the location data is not already set.</p>
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<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">updateLocationDataIfMissing</span>: <span class="hljs-function"><span class="hljs-params">(locationData)</span> -></span>
<span class="hljs-keyword">return</span> <span class="hljs-keyword">this</span> <span class="hljs-keyword">if</span> <span class="hljs-property">@locationData</span>
<span class="hljs-property">@locationData</span> = locationData
<span class="hljs-property">@eachChild</span> <span class="hljs-function"><span class="hljs-params">(child)</span> -></span>
child.updateLocationDataIfMissing locationData</pre></div></div>
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<p>Throw a SyntaxError associated with this node’s location.</p>
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<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">error</span>: <span class="hljs-function"><span class="hljs-params">(message)</span> -></span>
throwSyntaxError message, <span class="hljs-property">@locationData</span>
<span class="hljs-attribute">makeCode</span>: <span class="hljs-function"><span class="hljs-params">(code)</span> -></span>
<span class="hljs-keyword">new</span> CodeFragment <span class="hljs-keyword">this</span>, code
<span class="hljs-attribute">wrapInBraces</span>: <span class="hljs-function"><span class="hljs-params">(fragments)</span> -></span>
[].concat <span class="hljs-property">@makeCode</span>(<span class="hljs-string">'('</span>), fragments, <span class="hljs-property">@makeCode</span>(<span class="hljs-string">')'</span>)</pre></div></div>
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<p><code>fragmentsList</code> is an array of arrays of fragments. Each array in fragmentsList will be
concatonated together, with <code>joinStr</code> added in between each, to produce a final flat array
of fragments.</p>
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<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">joinFragmentArrays</span>: <span class="hljs-function"><span class="hljs-params">(fragmentsList, joinStr)</span> -></span>
answer = []
<span class="hljs-keyword">for</span> fragments,i <span class="hljs-keyword">in</span> fragmentsList
<span class="hljs-keyword">if</span> i <span class="hljs-keyword">then</span> answer.push <span class="hljs-property">@makeCode</span> joinStr
answer = answer.concat fragments
answer</pre></div></div>
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<h3 id="block">Block</h3>
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<p>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
<code>if</code>, <code>switch</code>, or <code>try</code>, and so on…</p>
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<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.Block = <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">Block</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">Base</span></span>
<span class="hljs-attribute">constructor</span>: <span class="hljs-function"><span class="hljs-params">(nodes)</span> -></span>
<span class="hljs-property">@expressions</span> = compact flatten nodes <span class="hljs-keyword">or</span> []
<span class="hljs-attribute">children</span>: [<span class="hljs-string">'expressions'</span>]</pre></div></div>
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<p>Tack an expression on to the end of this expression list.</p>
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<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">push</span>: <span class="hljs-function"><span class="hljs-params">(node)</span> -></span>
<span class="hljs-property">@expressions</span>.push node
<span class="hljs-keyword">this</span></pre></div></div>
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<p>Remove and return the last expression of this expression list.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">pop</span>:<span class="hljs-function"> -></span>
<span class="hljs-property">@expressions</span>.pop()</pre></div></div>
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<p>Add an expression at the beginning of this expression list.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">unshift</span>: <span class="hljs-function"><span class="hljs-params">(node)</span> -></span>
<span class="hljs-property">@expressions</span>.unshift node
<span class="hljs-keyword">this</span></pre></div></div>
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<p>If this Block consists of just a single node, unwrap it by pulling
it back out.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">unwrap</span>:<span class="hljs-function"> -></span>
<span class="hljs-keyword">if</span> <span class="hljs-property">@expressions</span>.length <span class="hljs-keyword">is</span> <span class="hljs-number">1</span> <span class="hljs-keyword">then</span> <span class="hljs-property">@expressions</span>[<span class="hljs-number">0</span>] <span class="hljs-keyword">else</span> <span class="hljs-keyword">this</span></pre></div></div>
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<p>Is this an empty block of code?</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">isEmpty</span>:<span class="hljs-function"> -></span>
<span class="hljs-keyword">not</span> <span class="hljs-property">@expressions</span>.length
<span class="hljs-attribute">isStatement</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
<span class="hljs-keyword">for</span> exp <span class="hljs-keyword">in</span> <span class="hljs-property">@expressions</span> <span class="hljs-keyword">when</span> exp.isStatement o
<span class="hljs-keyword">return</span> <span class="hljs-literal">yes</span>
<span class="hljs-literal">no</span>
<span class="hljs-attribute">jumps</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
<span class="hljs-keyword">for</span> exp <span class="hljs-keyword">in</span> <span class="hljs-property">@expressions</span>
<span class="hljs-keyword">return</span> jumpNode <span class="hljs-keyword">if</span> jumpNode = exp.jumps o</pre></div></div>
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<p>A Block node does not return its entire body, rather it
ensures that the final expression is returned.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">makeReturn</span>: <span class="hljs-function"><span class="hljs-params">(res)</span> -></span>
len = <span class="hljs-property">@expressions</span>.length
<span class="hljs-keyword">while</span> len--
expr = <span class="hljs-property">@expressions</span>[len]
<span class="hljs-keyword">if</span> expr <span class="hljs-keyword">not</span> <span class="hljs-keyword">instanceof</span> Comment
<span class="hljs-property">@expressions</span>[len] = expr.makeReturn res
<span class="hljs-property">@expressions</span>.splice(len, <span class="hljs-number">1</span>) <span class="hljs-keyword">if</span> expr <span class="hljs-keyword">instanceof</span> Return <span class="hljs-keyword">and</span> <span class="hljs-keyword">not</span> expr.expression
<span class="hljs-keyword">break</span>
<span class="hljs-keyword">this</span></pre></div></div>
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<p>A <strong>Block</strong> is the only node that can serve as the root.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">compileToFragments</span>: <span class="hljs-function"><span class="hljs-params">(o = {}, level)</span> -></span>
<span class="hljs-keyword">if</span> o.scope <span class="hljs-keyword">then</span> <span class="hljs-keyword">super</span> o, level <span class="hljs-keyword">else</span> <span class="hljs-property">@compileRoot</span> o</pre></div></div>
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<p>Compile all expressions within the <strong>Block</strong> 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.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">compileNode</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
<span class="hljs-property">@tab</span> = o.indent
top = o.level <span class="hljs-keyword">is</span> LEVEL_TOP
compiledNodes = []
<span class="hljs-keyword">for</span> node, index <span class="hljs-keyword">in</span> <span class="hljs-property">@expressions</span>
node = node.unwrapAll()
node = (node.unfoldSoak(o) <span class="hljs-keyword">or</span> node)
<span class="hljs-keyword">if</span> node <span class="hljs-keyword">instanceof</span> Block</pre></div></div>
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<p>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</p>
</div>
<div class="content"><div class='highlight'><pre> compiledNodes.push node.compileNode o
<span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> top
node.front = <span class="hljs-literal">true</span>
fragments = node.compileToFragments o
<span class="hljs-keyword">unless</span> node.isStatement o
fragments.unshift <span class="hljs-property">@makeCode</span> <span class="hljs-string">"<span class="hljs-subst">#{<span class="hljs-property">@tab</span>}</span>"</span>
fragments.push <span class="hljs-property">@makeCode</span> <span class="hljs-string">";"</span>
compiledNodes.push fragments
<span class="hljs-keyword">else</span>
compiledNodes.push node.compileToFragments o, LEVEL_LIST
<span class="hljs-keyword">if</span> top
<span class="hljs-keyword">if</span> <span class="hljs-property">@spaced</span>
<span class="hljs-keyword">return</span> [].concat <span class="hljs-property">@joinFragmentArrays</span>(compiledNodes, <span class="hljs-string">'\n\n'</span>), <span class="hljs-property">@makeCode</span>(<span class="hljs-string">"\n"</span>)
<span class="hljs-keyword">else</span>
<span class="hljs-keyword">return</span> <span class="hljs-property">@joinFragmentArrays</span>(compiledNodes, <span class="hljs-string">'\n'</span>)
<span class="hljs-keyword">if</span> compiledNodes.length
answer = <span class="hljs-property">@joinFragmentArrays</span>(compiledNodes, <span class="hljs-string">', '</span>)
<span class="hljs-keyword">else</span>
answer = [<span class="hljs-property">@makeCode</span> <span class="hljs-string">"void 0"</span>]
<span class="hljs-keyword">if</span> compiledNodes.length > <span class="hljs-number">1</span> <span class="hljs-keyword">and</span> o.level >= LEVEL_LIST <span class="hljs-keyword">then</span> <span class="hljs-property">@wrapInBraces</span> answer <span class="hljs-keyword">else</span> answer</pre></div></div>
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<p>If we happen to be the top-level <strong>Block</strong>, 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.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">compileRoot</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
o.indent = <span class="hljs-keyword">if</span> o.bare <span class="hljs-keyword">then</span> <span class="hljs-string">''</span> <span class="hljs-keyword">else</span> TAB
o.level = LEVEL_TOP
<span class="hljs-property">@spaced</span> = <span class="hljs-literal">yes</span>
o.scope = <span class="hljs-keyword">new</span> Scope <span class="hljs-literal">null</span>, <span class="hljs-keyword">this</span>, <span class="hljs-literal">null</span>, o.referencedVars ? []</pre></div></div>
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<p>Mark given local variables in the root scope as parameters so they don’t
end up being declared on this block.</p>
</div>
<div class="content"><div class='highlight'><pre> o.scope.parameter name <span class="hljs-keyword">for</span> name <span class="hljs-keyword">in</span> o.locals <span class="hljs-keyword">or</span> []
prelude = []
<span class="hljs-keyword">unless</span> o.bare
preludeExps = <span class="hljs-keyword">for</span> exp, i <span class="hljs-keyword">in</span> <span class="hljs-property">@expressions</span>
<span class="hljs-keyword">break</span> <span class="hljs-keyword">unless</span> exp.unwrap() <span class="hljs-keyword">instanceof</span> Comment
exp
rest = <span class="hljs-property">@expressions</span>[preludeExps.length...]
<span class="hljs-property">@expressions</span> = preludeExps
<span class="hljs-keyword">if</span> preludeExps.length
prelude = <span class="hljs-property">@compileNode</span> merge(o, <span class="hljs-attribute">indent</span>: <span class="hljs-string">''</span>)
prelude.push <span class="hljs-property">@makeCode</span> <span class="hljs-string">"\n"</span>
<span class="hljs-property">@expressions</span> = rest
fragments = <span class="hljs-property">@compileWithDeclarations</span> o
<span class="hljs-keyword">return</span> fragments <span class="hljs-keyword">if</span> o.bare
[].concat prelude, <span class="hljs-property">@makeCode</span>(<span class="hljs-string">"(function() {\n"</span>), fragments, <span class="hljs-property">@makeCode</span>(<span class="hljs-string">"\n}).call(this);\n"</span>)</pre></div></div>
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<p>Compile the expressions body for the contents of a function, with
declarations of all inner variables pushed up to the top.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">compileWithDeclarations</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
fragments = []
post = []
<span class="hljs-keyword">for</span> exp, i <span class="hljs-keyword">in</span> <span class="hljs-property">@expressions</span>
exp = exp.unwrap()
<span class="hljs-keyword">break</span> <span class="hljs-keyword">unless</span> exp <span class="hljs-keyword">instanceof</span> Comment <span class="hljs-keyword">or</span> exp <span class="hljs-keyword">instanceof</span> Literal
o = merge(o, <span class="hljs-attribute">level</span>: LEVEL_TOP)
<span class="hljs-keyword">if</span> i
rest = <span class="hljs-property">@expressions</span>.splice i, <span class="hljs-number">9e9</span>
[spaced, <span class="hljs-property">@spaced</span>] = [<span class="hljs-property">@spaced</span>, <span class="hljs-literal">no</span>]
[fragments, <span class="hljs-property">@spaced</span>] = [<span class="hljs-property">@compileNode</span>(o), spaced]
<span class="hljs-property">@expressions</span> = rest
post = <span class="hljs-property">@compileNode</span> o
{scope} = o
<span class="hljs-keyword">if</span> scope.expressions <span class="hljs-keyword">is</span> <span class="hljs-keyword">this</span>
declars = o.scope.hasDeclarations()
assigns = scope.hasAssignments
<span class="hljs-keyword">if</span> declars <span class="hljs-keyword">or</span> assigns
fragments.push <span class="hljs-property">@makeCode</span> <span class="hljs-string">'\n'</span> <span class="hljs-keyword">if</span> i
fragments.push <span class="hljs-property">@makeCode</span> <span class="hljs-string">"<span class="hljs-subst">#{<span class="hljs-property">@tab</span>}</span>var "</span>
<span class="hljs-keyword">if</span> declars
fragments.push <span class="hljs-property">@makeCode</span> scope.declaredVariables().join(<span class="hljs-string">', '</span>)
<span class="hljs-keyword">if</span> assigns
fragments.push <span class="hljs-property">@makeCode</span> <span class="hljs-string">",\n<span class="hljs-subst">#{<span class="hljs-property">@tab</span> + TAB}</span>"</span> <span class="hljs-keyword">if</span> declars
fragments.push <span class="hljs-property">@makeCode</span> scope.assignedVariables().join(<span class="hljs-string">",\n<span class="hljs-subst">#{<span class="hljs-property">@tab</span> + TAB}</span>"</span>)
fragments.push <span class="hljs-property">@makeCode</span> <span class="hljs-string">";\n<span class="hljs-subst">#{<span class="hljs-keyword">if</span> <span class="hljs-property">@spaced</span> <span class="hljs-keyword">then</span> <span class="hljs-string">'\n'</span> <span class="hljs-keyword">else</span> <span class="hljs-string">''</span>}</span>"</span>
<span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> fragments.length <span class="hljs-keyword">and</span> post.length
fragments.push <span class="hljs-property">@makeCode</span> <span class="hljs-string">"\n"</span>
fragments.concat post</pre></div></div>
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<p>Wrap up the given nodes as a <strong>Block</strong>, unless it already happens
to be one.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-property">@wrap</span>: <span class="hljs-function"><span class="hljs-params">(nodes)</span> -></span>
<span class="hljs-keyword">return</span> nodes[<span class="hljs-number">0</span>] <span class="hljs-keyword">if</span> nodes.length <span class="hljs-keyword">is</span> <span class="hljs-number">1</span> <span class="hljs-keyword">and</span> nodes[<span class="hljs-number">0</span>] <span class="hljs-keyword">instanceof</span> Block
<span class="hljs-keyword">new</span> Block nodes</pre></div></div>
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<h3 id="literal">Literal</h3>
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<p>Literals are static values that can be passed through directly into
JavaScript without translation, such as: strings, numbers,
<code>true</code>, <code>false</code>, <code>null</code>…</p>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.Literal = <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">Literal</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">Base</span></span>
<span class="hljs-attribute">constructor</span>: <span class="hljs-function"><span class="hljs-params">(<span class="hljs-property">@value</span>)</span> -></span>
<span class="hljs-attribute">makeReturn</span>:<span class="hljs-function"> -></span>
<span class="hljs-keyword">if</span> <span class="hljs-property">@isStatement</span>() <span class="hljs-keyword">then</span> <span class="hljs-keyword">this</span> <span class="hljs-keyword">else</span> <span class="hljs-keyword">super</span>
<span class="hljs-attribute">isAssignable</span>:<span class="hljs-function"> -></span>
IDENTIFIER.test <span class="hljs-property">@value</span>
<span class="hljs-attribute">isStatement</span>:<span class="hljs-function"> -></span>
<span class="hljs-property">@value</span> <span class="hljs-keyword">in</span> [<span class="hljs-string">'break'</span>, <span class="hljs-string">'continue'</span>, <span class="hljs-string">'debugger'</span>]
<span class="hljs-attribute">isComplex</span>: NO
<span class="hljs-attribute">assigns</span>: <span class="hljs-function"><span class="hljs-params">(name)</span> -></span>
name <span class="hljs-keyword">is</span> <span class="hljs-property">@value</span>
<span class="hljs-attribute">jumps</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
<span class="hljs-keyword">return</span> <span class="hljs-keyword">this</span> <span class="hljs-keyword">if</span> <span class="hljs-property">@value</span> <span class="hljs-keyword">is</span> <span class="hljs-string">'break'</span> <span class="hljs-keyword">and</span> <span class="hljs-keyword">not</span> (o?.<span class="hljs-keyword">loop</span> <span class="hljs-keyword">or</span> o?.block)
<span class="hljs-keyword">return</span> <span class="hljs-keyword">this</span> <span class="hljs-keyword">if</span> <span class="hljs-property">@value</span> <span class="hljs-keyword">is</span> <span class="hljs-string">'continue'</span> <span class="hljs-keyword">and</span> <span class="hljs-keyword">not</span> o?.<span class="hljs-keyword">loop</span>
<span class="hljs-attribute">compileNode</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
code = <span class="hljs-keyword">if</span> <span class="hljs-property">@value</span> <span class="hljs-keyword">is</span> <span class="hljs-string">'this'</span>
<span class="hljs-keyword">if</span> o.scope.method?.bound <span class="hljs-keyword">then</span> o.scope.method.context <span class="hljs-keyword">else</span> <span class="hljs-property">@value</span>
<span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> <span class="hljs-property">@value</span>.reserved
<span class="hljs-string">"\"<span class="hljs-subst">#{<span class="hljs-property">@value</span>}</span>\""</span>
<span class="hljs-keyword">else</span>
<span class="hljs-property">@value</span>
answer = <span class="hljs-keyword">if</span> <span class="hljs-property">@isStatement</span>() <span class="hljs-keyword">then</span> <span class="hljs-string">"<span class="hljs-subst">#{<span class="hljs-property">@tab</span>}</span><span class="hljs-subst">#{code}</span>;"</span> <span class="hljs-keyword">else</span> code
[<span class="hljs-property">@makeCode</span> answer]
<span class="hljs-attribute">toString</span>:<span class="hljs-function"> -></span>
<span class="hljs-string">' "'</span> + <span class="hljs-property">@value</span> + <span class="hljs-string">'"'</span>
<span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">exports</span>.<span class="hljs-title">Undefined</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">Base</span></span>
<span class="hljs-attribute">isAssignable</span>: NO
<span class="hljs-attribute">isComplex</span>: NO
<span class="hljs-attribute">compileNode</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
[<span class="hljs-property">@makeCode</span> <span class="hljs-keyword">if</span> o.level >= LEVEL_ACCESS <span class="hljs-keyword">then</span> <span class="hljs-string">'(void 0)'</span> <span class="hljs-keyword">else</span> <span class="hljs-string">'void 0'</span>]
<span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">exports</span>.<span class="hljs-title">Null</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">Base</span></span>
<span class="hljs-attribute">isAssignable</span>: NO
<span class="hljs-attribute">isComplex</span>: NO
<span class="hljs-attribute">compileNode</span>:<span class="hljs-function"> -></span> [<span class="hljs-property">@makeCode</span> <span class="hljs-string">"null"</span>]
<span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">exports</span>.<span class="hljs-title">Bool</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">Base</span></span>
<span class="hljs-attribute">isAssignable</span>: NO
<span class="hljs-attribute">isComplex</span>: NO
<span class="hljs-attribute">compileNode</span>:<span class="hljs-function"> -></span> [<span class="hljs-property">@makeCode</span> <span class="hljs-property">@val</span>]
<span class="hljs-attribute">constructor</span>: <span class="hljs-function"><span class="hljs-params">(<span class="hljs-property">@val</span>)</span> -></span></pre></div></div>
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<h3 id="return">Return</h3>
</div>
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<p>A <code>return</code> is a <em>pureStatement</em> — wrapping it in a closure wouldn’t
make sense.</p>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.Return = <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">Return</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">Base</span></span>
<span class="hljs-attribute">constructor</span>: <span class="hljs-function"><span class="hljs-params">(<span class="hljs-property">@expression</span>)</span> -></span>
<span class="hljs-attribute">children</span>: [<span class="hljs-string">'expression'</span>]
<span class="hljs-attribute">isStatement</span>: YES
<span class="hljs-attribute">makeReturn</span>: THIS
<span class="hljs-attribute">jumps</span>: THIS
<span class="hljs-attribute">compileToFragments</span>: <span class="hljs-function"><span class="hljs-params">(o, level)</span> -></span>
expr = <span class="hljs-property">@expression</span>?.makeReturn()
<span class="hljs-keyword">if</span> expr <span class="hljs-keyword">and</span> expr <span class="hljs-keyword">not</span> <span class="hljs-keyword">instanceof</span> Return <span class="hljs-keyword">then</span> expr.compileToFragments o, level <span class="hljs-keyword">else</span> <span class="hljs-keyword">super</span> o, level
<span class="hljs-attribute">compileNode</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
answer = []
exprIsYieldReturn = <span class="hljs-property">@expression</span>?.isYieldReturn?()</pre></div></div>
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<p>TODO: If we call expression.compile() here twice, we’ll sometimes get back different results!</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-keyword">unless</span> exprIsYieldReturn
answer.push <span class="hljs-property">@makeCode</span> <span class="hljs-property">@tab</span> + <span class="hljs-string">"return<span class="hljs-subst">#{<span class="hljs-keyword">if</span> <span class="hljs-property">@expression</span> <span class="hljs-keyword">then</span> <span class="hljs-string">" "</span> <span class="hljs-keyword">else</span> <span class="hljs-string">""</span>}</span>"</span>
<span class="hljs-keyword">if</span> <span class="hljs-property">@expression</span>
answer = answer.concat <span class="hljs-property">@expression</span>.compileToFragments o, LEVEL_PAREN
answer.push <span class="hljs-property">@makeCode</span> <span class="hljs-string">";"</span> <span class="hljs-keyword">unless</span> exprIsYieldReturn
<span class="hljs-keyword">return</span> answer</pre></div></div>
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<h3 id="value">Value</h3>
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<p>A value, variable or literal or parenthesized, indexed or dotted into,
or vanilla.</p>
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<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.Value = <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">Value</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">Base</span></span>
<span class="hljs-attribute">constructor</span>: <span class="hljs-function"><span class="hljs-params">(base, props, tag)</span> -></span>
<span class="hljs-keyword">return</span> base <span class="hljs-keyword">if</span> <span class="hljs-keyword">not</span> props <span class="hljs-keyword">and</span> base <span class="hljs-keyword">instanceof</span> Value
<span class="hljs-property">@base</span> = base
<span class="hljs-property">@properties</span> = props <span class="hljs-keyword">or</span> []
@[tag] = <span class="hljs-literal">true</span> <span class="hljs-keyword">if</span> tag
<span class="hljs-keyword">return</span> <span class="hljs-keyword">this</span>
<span class="hljs-attribute">children</span>: [<span class="hljs-string">'base'</span>, <span class="hljs-string">'properties'</span>]</pre></div></div>
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<p>Add a property (or <em>properties</em> ) <code>Access</code> to the list.</p>
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<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">add</span>: <span class="hljs-function"><span class="hljs-params">(props)</span> -></span>
<span class="hljs-property">@properties</span> = <span class="hljs-property">@properties</span>.concat props
<span class="hljs-keyword">this</span>
<span class="hljs-attribute">hasProperties</span>:<span class="hljs-function"> -></span>
!!<span class="hljs-property">@properties</span>.length
<span class="hljs-attribute">bareLiteral</span>: <span class="hljs-function"><span class="hljs-params">(type)</span> -></span>
<span class="hljs-keyword">not</span> <span class="hljs-property">@properties</span>.length <span class="hljs-keyword">and</span> <span class="hljs-property">@base</span> <span class="hljs-keyword">instanceof</span> type</pre></div></div>
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<p>Some boolean checks for the benefit of other nodes.</p>
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<div class="content"><div class='highlight'><pre> isArray :<span class="hljs-function"> -></span> <span class="hljs-property">@bareLiteral</span>(Arr)
isRange :<span class="hljs-function"> -></span> <span class="hljs-property">@bareLiteral</span>(Range)
isComplex :<span class="hljs-function"> -></span> <span class="hljs-property">@hasProperties</span>() <span class="hljs-keyword">or</span> <span class="hljs-property">@base</span>.isComplex()
isAssignable :<span class="hljs-function"> -></span> <span class="hljs-property">@hasProperties</span>() <span class="hljs-keyword">or</span> <span class="hljs-property">@base</span>.isAssignable()
isSimpleNumber :<span class="hljs-function"> -></span> <span class="hljs-property">@bareLiteral</span>(Literal) <span class="hljs-keyword">and</span> SIMPLENUM.test <span class="hljs-property">@base</span>.value
isString :<span class="hljs-function"> -></span> <span class="hljs-property">@bareLiteral</span>(Literal) <span class="hljs-keyword">and</span> IS_STRING.test <span class="hljs-property">@base</span>.value
isRegex :<span class="hljs-function"> -></span> <span class="hljs-property">@bareLiteral</span>(Literal) <span class="hljs-keyword">and</span> IS_REGEX.test <span class="hljs-property">@base</span>.value
isAtomic :<span class="hljs-function"> -></span>
<span class="hljs-keyword">for</span> node <span class="hljs-keyword">in</span> <span class="hljs-property">@properties</span>.concat <span class="hljs-property">@base</span>
<span class="hljs-keyword">return</span> <span class="hljs-literal">no</span> <span class="hljs-keyword">if</span> node.soak <span class="hljs-keyword">or</span> node <span class="hljs-keyword">instanceof</span> Call
<span class="hljs-literal">yes</span>
isNotCallable :<span class="hljs-function"> -></span> <span class="hljs-property">@isSimpleNumber</span>() <span class="hljs-keyword">or</span> <span class="hljs-property">@isString</span>() <span class="hljs-keyword">or</span> <span class="hljs-property">@isRegex</span>() <span class="hljs-keyword">or</span>
<span class="hljs-property">@isArray</span>() <span class="hljs-keyword">or</span> <span class="hljs-property">@isRange</span>() <span class="hljs-keyword">or</span> <span class="hljs-property">@isSplice</span>() <span class="hljs-keyword">or</span> <span class="hljs-property">@isObject</span>()
isStatement : <span class="hljs-function"><span class="hljs-params">(o)</span> -></span> <span class="hljs-keyword">not</span> <span class="hljs-property">@properties</span>.length <span class="hljs-keyword">and</span> <span class="hljs-property">@base</span>.isStatement o
assigns : <span class="hljs-function"><span class="hljs-params">(name)</span> -></span> <span class="hljs-keyword">not</span> <span class="hljs-property">@properties</span>.length <span class="hljs-keyword">and</span> <span class="hljs-property">@base</span>.assigns name
jumps : <span class="hljs-function"><span class="hljs-params">(o)</span> -></span> <span class="hljs-keyword">not</span> <span class="hljs-property">@properties</span>.length <span class="hljs-keyword">and</span> <span class="hljs-property">@base</span>.jumps o
<span class="hljs-attribute">isObject</span>: <span class="hljs-function"><span class="hljs-params">(onlyGenerated)</span> -></span>
<span class="hljs-keyword">return</span> <span class="hljs-literal">no</span> <span class="hljs-keyword">if</span> <span class="hljs-property">@properties</span>.length
(<span class="hljs-property">@base</span> <span class="hljs-keyword">instanceof</span> Obj) <span class="hljs-keyword">and</span> (<span class="hljs-keyword">not</span> onlyGenerated <span class="hljs-keyword">or</span> <span class="hljs-property">@base</span>.generated)
<span class="hljs-attribute">isSplice</span>:<span class="hljs-function"> -></span>
[..., lastProp] = <span class="hljs-property">@properties</span>
lastProp <span class="hljs-keyword">instanceof</span> Slice
<span class="hljs-attribute">looksStatic</span>: <span class="hljs-function"><span class="hljs-params">(className)</span> -></span>
<span class="hljs-property">@base</span>.value <span class="hljs-keyword">is</span> className <span class="hljs-keyword">and</span> <span class="hljs-property">@properties</span>.length <span class="hljs-keyword">is</span> <span class="hljs-number">1</span> <span class="hljs-keyword">and</span>
<span class="hljs-property">@properties</span>[<span class="hljs-number">0</span>].name?.value <span class="hljs-keyword">isnt</span> <span class="hljs-string">'prototype'</span></pre></div></div>
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<p>The value can be unwrapped as its inner node, if there are no attached
properties.</p>
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<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">unwrap</span>:<span class="hljs-function"> -></span>
<span class="hljs-keyword">if</span> <span class="hljs-property">@properties</span>.length <span class="hljs-keyword">then</span> <span class="hljs-keyword">this</span> <span class="hljs-keyword">else</span> <span class="hljs-property">@base</span></pre></div></div>
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<p>A reference has base part (<code>this</code> value) and name part.
We cache them separately for compiling complex expressions.
<code>a()[b()] ?= c</code> -> <code>(_base = a())[_name = b()] ? _base[_name] = c</code></p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">cacheReference</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
[..., name] = <span class="hljs-property">@properties</span>
<span class="hljs-keyword">if</span> <span class="hljs-property">@properties</span>.length < <span class="hljs-number">2</span> <span class="hljs-keyword">and</span> <span class="hljs-keyword">not</span> <span class="hljs-property">@base</span>.isComplex() <span class="hljs-keyword">and</span> <span class="hljs-keyword">not</span> name?.isComplex()
<span class="hljs-keyword">return</span> [<span class="hljs-keyword">this</span>, <span class="hljs-keyword">this</span>] <span class="hljs-comment"># `a` `a.b`</span>
base = <span class="hljs-keyword">new</span> Value <span class="hljs-property">@base</span>, <span class="hljs-property">@properties</span>[...-<span class="hljs-number">1</span>]
<span class="hljs-keyword">if</span> base.isComplex() <span class="hljs-comment"># `a().b`</span>
bref = <span class="hljs-keyword">new</span> Literal o.scope.freeVariable <span class="hljs-string">'base'</span>
base = <span class="hljs-keyword">new</span> Value <span class="hljs-keyword">new</span> Parens <span class="hljs-keyword">new</span> Assign bref, base
<span class="hljs-keyword">return</span> [base, bref] <span class="hljs-keyword">unless</span> name <span class="hljs-comment"># `a()`</span>
<span class="hljs-keyword">if</span> name.isComplex() <span class="hljs-comment"># `a[b()]`</span>
nref = <span class="hljs-keyword">new</span> Literal o.scope.freeVariable <span class="hljs-string">'name'</span>
name = <span class="hljs-keyword">new</span> Index <span class="hljs-keyword">new</span> Assign nref, name.index
nref = <span class="hljs-keyword">new</span> Index nref
[base.add(name), <span class="hljs-keyword">new</span> Value(bref <span class="hljs-keyword">or</span> base.base, [nref <span class="hljs-keyword">or</span> name])]</pre></div></div>
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<p>We compile a value to JavaScript by compiling and joining each property.
Things get much more interesting if the chain of properties has <em>soak</em>
operators <code>?.</code> interspersed. Then we have to take care not to accidentally
evaluate anything twice when building the soak chain.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">compileNode</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
<span class="hljs-property">@base</span>.front = <span class="hljs-property">@front</span>
props = <span class="hljs-property">@properties</span>
fragments = <span class="hljs-property">@base</span>.compileToFragments o, (<span class="hljs-keyword">if</span> props.length <span class="hljs-keyword">then</span> LEVEL_ACCESS <span class="hljs-keyword">else</span> <span class="hljs-literal">null</span>)
<span class="hljs-keyword">if</span> (<span class="hljs-property">@base</span> <span class="hljs-keyword">instanceof</span> Parens <span class="hljs-keyword">or</span> props.length) <span class="hljs-keyword">and</span> SIMPLENUM.test fragmentsToText fragments
fragments.push <span class="hljs-property">@makeCode</span> <span class="hljs-string">'.'</span>
<span class="hljs-keyword">for</span> prop <span class="hljs-keyword">in</span> props
fragments.push (prop.compileToFragments o)...
fragments</pre></div></div>
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<p>Unfold a soak into an <code>If</code>: <code>a?.b</code> -> <code>a.b if a?</code></p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">unfoldSoak</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
<span class="hljs-property">@unfoldedSoak</span> ?= <span class="hljs-keyword">do</span><span class="hljs-function"> =></span>
<span class="hljs-keyword">if</span> ifn = <span class="hljs-property">@base</span>.unfoldSoak o
ifn.body.properties.push <span class="hljs-property">@properties</span>...
<span class="hljs-keyword">return</span> ifn
<span class="hljs-keyword">for</span> prop, i <span class="hljs-keyword">in</span> <span class="hljs-property">@properties</span> <span class="hljs-keyword">when</span> prop.soak
prop.soak = <span class="hljs-literal">off</span>
fst = <span class="hljs-keyword">new</span> Value <span class="hljs-property">@base</span>, <span class="hljs-property">@properties</span>[...i]
snd = <span class="hljs-keyword">new</span> Value <span class="hljs-property">@base</span>, <span class="hljs-property">@properties</span>[i..]
<span class="hljs-keyword">if</span> fst.isComplex()
ref = <span class="hljs-keyword">new</span> Literal o.scope.freeVariable <span class="hljs-string">'ref'</span>
fst = <span class="hljs-keyword">new</span> Parens <span class="hljs-keyword">new</span> Assign ref, fst
snd.base = ref
<span class="hljs-keyword">return</span> <span class="hljs-keyword">new</span> If <span class="hljs-keyword">new</span> Existence(fst), snd, <span class="hljs-attribute">soak</span>: <span class="hljs-literal">on</span>
<span class="hljs-literal">no</span></pre></div></div>
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<h3 id="comment">Comment</h3>
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<p>CoffeeScript passes through block comments as JavaScript block comments
at the same position.</p>
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<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.Comment = <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">Comment</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">Base</span></span>
<span class="hljs-attribute">constructor</span>: <span class="hljs-function"><span class="hljs-params">(<span class="hljs-property">@comment</span>)</span> -></span>
<span class="hljs-attribute">isStatement</span>: YES
<span class="hljs-attribute">makeReturn</span>: THIS
<span class="hljs-attribute">compileNode</span>: <span class="hljs-function"><span class="hljs-params">(o, level)</span> -></span>
comment = <span class="hljs-property">@comment</span>.replace <span class="hljs-regexp">/^(\s*)#(?=\s)/gm</span>, <span class="hljs-string">"$1 *"</span>
code = <span class="hljs-string">"/*<span class="hljs-subst">#{multident comment, <span class="hljs-property">@tab</span>}</span><span class="hljs-subst">#{<span class="hljs-keyword">if</span> <span class="hljs-string">'\n'</span> <span class="hljs-keyword">in</span> comment <span class="hljs-keyword">then</span> <span class="hljs-string">"\n<span class="hljs-subst">#{<span class="hljs-property">@tab</span>}</span>"</span> <span class="hljs-keyword">else</span> <span class="hljs-string">''</span>}</span> */"</span>
code = o.indent + code <span class="hljs-keyword">if</span> (level <span class="hljs-keyword">or</span> o.level) <span class="hljs-keyword">is</span> LEVEL_TOP
[<span class="hljs-property">@makeCode</span>(<span class="hljs-string">"\n"</span>), <span class="hljs-property">@makeCode</span>(code)]</pre></div></div>
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<h3 id="call">Call</h3>
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<p>Node for a function invocation. Takes care of converting <code>super()</code> calls into
calls against the prototype’s function of the same name.</p>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.Call = <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">Call</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">Base</span></span>
<span class="hljs-attribute">constructor</span>: <span class="hljs-function"><span class="hljs-params">(variable, <span class="hljs-property">@args</span> = [], <span class="hljs-property">@soak</span>)</span> -></span>
<span class="hljs-property">@isNew</span> = <span class="hljs-literal">false</span>
<span class="hljs-property">@isSuper</span> = variable <span class="hljs-keyword">is</span> <span class="hljs-string">'super'</span>
<span class="hljs-property">@variable</span> = <span class="hljs-keyword">if</span> <span class="hljs-property">@isSuper</span> <span class="hljs-keyword">then</span> <span class="hljs-literal">null</span> <span class="hljs-keyword">else</span> variable
<span class="hljs-keyword">if</span> variable <span class="hljs-keyword">instanceof</span> Value <span class="hljs-keyword">and</span> variable.isNotCallable()
variable.error <span class="hljs-string">"literal is not a function"</span>
<span class="hljs-attribute">children</span>: [<span class="hljs-string">'variable'</span>, <span class="hljs-string">'args'</span>]</pre></div></div>
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<p>Tag this invocation as creating a new instance.</p>
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<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">newInstance</span>:<span class="hljs-function"> -></span>
base = <span class="hljs-property">@variable</span>?.base <span class="hljs-keyword">or</span> <span class="hljs-property">@variable</span>
<span class="hljs-keyword">if</span> base <span class="hljs-keyword">instanceof</span> Call <span class="hljs-keyword">and</span> <span class="hljs-keyword">not</span> base.isNew
base.newInstance()
<span class="hljs-keyword">else</span>
<span class="hljs-property">@isNew</span> = <span class="hljs-literal">true</span>
<span class="hljs-keyword">this</span></pre></div></div>
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<p>Grab the reference to the superclass’s implementation of the current
method.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">superReference</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
method = o.scope.namedMethod()
<span class="hljs-keyword">if</span> method?.klass
{klass, name, variable} = method
<span class="hljs-keyword">if</span> klass.isComplex()
bref = <span class="hljs-keyword">new</span> Literal o.scope.parent.freeVariable <span class="hljs-string">'base'</span>
base = <span class="hljs-keyword">new</span> Value <span class="hljs-keyword">new</span> Parens <span class="hljs-keyword">new</span> Assign bref, klass
variable.base = base
variable.properties.splice <span class="hljs-number">0</span>, klass.properties.length
<span class="hljs-keyword">if</span> name.isComplex() <span class="hljs-keyword">or</span> (name <span class="hljs-keyword">instanceof</span> Index <span class="hljs-keyword">and</span> name.index.isAssignable())
nref = <span class="hljs-keyword">new</span> Literal o.scope.parent.freeVariable <span class="hljs-string">'name'</span>
name = <span class="hljs-keyword">new</span> Index <span class="hljs-keyword">new</span> Assign nref, name.index
variable.properties.pop()
variable.properties.push name
accesses = [<span class="hljs-keyword">new</span> Access <span class="hljs-keyword">new</span> Literal <span class="hljs-string">'__super__'</span>]
accesses.push <span class="hljs-keyword">new</span> Access <span class="hljs-keyword">new</span> Literal <span class="hljs-string">'constructor'</span> <span class="hljs-keyword">if</span> method.static
accesses.push <span class="hljs-keyword">if</span> nref? <span class="hljs-keyword">then</span> <span class="hljs-keyword">new</span> Index nref <span class="hljs-keyword">else</span> name
(<span class="hljs-keyword">new</span> Value bref ? klass, accesses).compile o
<span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> method?.ctor
<span class="hljs-string">"<span class="hljs-subst">#{method.name}</span>.__super__.constructor"</span>
<span class="hljs-keyword">else</span>
<span class="hljs-property">@error</span> <span class="hljs-string">'cannot call super outside of an instance method.'</span></pre></div></div>
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<p>The appropriate <code>this</code> value for a <code>super</code> call.</p>
</div>
<div class="content"><div class='highlight'><pre> superThis : <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
method = o.scope.method
(method <span class="hljs-keyword">and</span> <span class="hljs-keyword">not</span> method.klass <span class="hljs-keyword">and</span> method.context) <span class="hljs-keyword">or</span> <span class="hljs-string">"this"</span></pre></div></div>
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<p>Soaked chained invocations unfold into if/else ternary structures.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">unfoldSoak</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
<span class="hljs-keyword">if</span> <span class="hljs-property">@soak</span>
<span class="hljs-keyword">if</span> <span class="hljs-property">@variable</span>
<span class="hljs-keyword">return</span> ifn <span class="hljs-keyword">if</span> ifn = unfoldSoak o, <span class="hljs-keyword">this</span>, <span class="hljs-string">'variable'</span>
[left, rite] = <span class="hljs-keyword">new</span> Value(<span class="hljs-property">@variable</span>).cacheReference o
<span class="hljs-keyword">else</span>
left = <span class="hljs-keyword">new</span> Literal <span class="hljs-property">@superReference</span> o
rite = <span class="hljs-keyword">new</span> Value left
rite = <span class="hljs-keyword">new</span> Call rite, <span class="hljs-property">@args</span>
rite.isNew = <span class="hljs-property">@isNew</span>
left = <span class="hljs-keyword">new</span> Literal <span class="hljs-string">"typeof <span class="hljs-subst">#{ left.compile o }</span> === \"function\""</span>
<span class="hljs-keyword">return</span> <span class="hljs-keyword">new</span> If left, <span class="hljs-keyword">new</span> Value(rite), <span class="hljs-attribute">soak</span>: <span class="hljs-literal">yes</span>
call = <span class="hljs-keyword">this</span>
list = []
<span class="hljs-keyword">loop</span>
<span class="hljs-keyword">if</span> call.variable <span class="hljs-keyword">instanceof</span> Call
list.push call
call = call.variable
<span class="hljs-keyword">continue</span>
<span class="hljs-keyword">break</span> <span class="hljs-keyword">unless</span> call.variable <span class="hljs-keyword">instanceof</span> Value
list.push call
<span class="hljs-keyword">break</span> <span class="hljs-keyword">unless</span> (call = call.variable.base) <span class="hljs-keyword">instanceof</span> Call
<span class="hljs-keyword">for</span> call <span class="hljs-keyword">in</span> list.reverse()
<span class="hljs-keyword">if</span> ifn
<span class="hljs-keyword">if</span> call.variable <span class="hljs-keyword">instanceof</span> Call
call.variable = ifn
<span class="hljs-keyword">else</span>
call.variable.base = ifn
ifn = unfoldSoak o, call, <span class="hljs-string">'variable'</span>
ifn</pre></div></div>
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<p>Compile a vanilla function call.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">compileNode</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
<span class="hljs-property">@variable</span>?.front = <span class="hljs-property">@front</span>
compiledArray = Splat.compileSplattedArray o, <span class="hljs-property">@args</span>, <span class="hljs-literal">true</span>
<span class="hljs-keyword">if</span> compiledArray.length
<span class="hljs-keyword">return</span> <span class="hljs-property">@compileSplat</span> o, compiledArray
compiledArgs = []
<span class="hljs-keyword">for</span> arg, argIndex <span class="hljs-keyword">in</span> <span class="hljs-property">@args</span>
<span class="hljs-keyword">if</span> argIndex <span class="hljs-keyword">then</span> compiledArgs.push <span class="hljs-property">@makeCode</span> <span class="hljs-string">", "</span>
compiledArgs.push (arg.compileToFragments o, LEVEL_LIST)...
fragments = []
<span class="hljs-keyword">if</span> <span class="hljs-property">@isSuper</span>
preface = <span class="hljs-property">@superReference</span>(o) + <span class="hljs-string">".call(<span class="hljs-subst">#{<span class="hljs-property">@superThis</span>(o)}</span>"</span>
<span class="hljs-keyword">if</span> compiledArgs.length <span class="hljs-keyword">then</span> preface += <span class="hljs-string">", "</span>
fragments.push <span class="hljs-property">@makeCode</span> preface
<span class="hljs-keyword">else</span>
<span class="hljs-keyword">if</span> <span class="hljs-property">@isNew</span> <span class="hljs-keyword">then</span> fragments.push <span class="hljs-property">@makeCode</span> <span class="hljs-string">'new '</span>
fragments.push <span class="hljs-property">@variable</span>.compileToFragments(o, LEVEL_ACCESS)...
fragments.push <span class="hljs-property">@makeCode</span> <span class="hljs-string">"("</span>
fragments.push compiledArgs...
fragments.push <span class="hljs-property">@makeCode</span> <span class="hljs-string">")"</span>
fragments</pre></div></div>
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<p>If you call a function with a splat, it’s converted into a JavaScript
<code>.apply()</code> 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.</p>
<p>splatArgs is an array of CodeFragments to put into the ‘apply’.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">compileSplat</span>: <span class="hljs-function"><span class="hljs-params">(o, splatArgs)</span> -></span>
<span class="hljs-keyword">if</span> <span class="hljs-property">@isSuper</span>
<span class="hljs-keyword">return</span> [].concat <span class="hljs-property">@makeCode</span>(<span class="hljs-string">"<span class="hljs-subst">#{ <span class="hljs-property">@superReference</span> o }</span>.apply(<span class="hljs-subst">#{<span class="hljs-property">@superThis</span>(o)}</span>, "</span>),
splatArgs, <span class="hljs-property">@makeCode</span>(<span class="hljs-string">")"</span>)
<span class="hljs-keyword">if</span> <span class="hljs-property">@isNew</span>
idt = <span class="hljs-property">@tab</span> + TAB
<span class="hljs-keyword">return</span> [].concat <span class="hljs-property">@makeCode</span>(<span class="hljs-string">"""
(function(func, args, ctor) {
<span class="hljs-subst">#{idt}</span>ctor.prototype = func.prototype;
<span class="hljs-subst">#{idt}</span>var child = new ctor, result = func.apply(child, args);
<span class="hljs-subst">#{idt}</span>return Object(result) === result ? result : child;
<span class="hljs-subst">#{<span class="hljs-property">@tab</span>}</span>})("""</span>),
(<span class="hljs-property">@variable</span>.compileToFragments o, LEVEL_LIST),
<span class="hljs-property">@makeCode</span>(<span class="hljs-string">", "</span>), splatArgs, <span class="hljs-property">@makeCode</span>(<span class="hljs-string">", function(){})"</span>)
answer = []
base = <span class="hljs-keyword">new</span> Value <span class="hljs-property">@variable</span>
<span class="hljs-keyword">if</span> (name = base.properties.pop()) <span class="hljs-keyword">and</span> base.isComplex()
ref = o.scope.freeVariable <span class="hljs-string">'ref'</span>
answer = answer.concat <span class="hljs-property">@makeCode</span>(<span class="hljs-string">"(<span class="hljs-subst">#{ref}</span> = "</span>),
(base.compileToFragments o, LEVEL_LIST),
<span class="hljs-property">@makeCode</span>(<span class="hljs-string">")"</span>),
name.compileToFragments(o)
<span class="hljs-keyword">else</span>
fun = base.compileToFragments o, LEVEL_ACCESS
fun = <span class="hljs-property">@wrapInBraces</span> fun <span class="hljs-keyword">if</span> SIMPLENUM.test fragmentsToText fun
<span class="hljs-keyword">if</span> name
ref = fragmentsToText fun
fun.push (name.compileToFragments o)...
<span class="hljs-keyword">else</span>
ref = <span class="hljs-string">'null'</span>
answer = answer.concat fun
answer = answer.concat <span class="hljs-property">@makeCode</span>(<span class="hljs-string">".apply(<span class="hljs-subst">#{ref}</span>, "</span>), splatArgs, <span class="hljs-property">@makeCode</span>(<span class="hljs-string">")"</span>)</pre></div></div>
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<h3 id="extends">Extends</h3>
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<p>Node to extend an object’s prototype with an ancestor object.
After <code>goog.inherits</code> from the
<a href="http://closure-library.googlecode.com/svn/docs/closureGoogBase.js.html">Closure Library</a>.</p>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.Extends = <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">Extends</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">Base</span></span>
<span class="hljs-attribute">constructor</span>: <span class="hljs-function"><span class="hljs-params">(<span class="hljs-property">@child</span>, <span class="hljs-property">@parent</span>)</span> -></span>
<span class="hljs-attribute">children</span>: [<span class="hljs-string">'child'</span>, <span class="hljs-string">'parent'</span>]</pre></div></div>
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<p>Hooks one constructor into another’s prototype chain.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">compileToFragments</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
<span class="hljs-keyword">new</span> Call(<span class="hljs-keyword">new</span> Value(<span class="hljs-keyword">new</span> Literal utility <span class="hljs-string">'extend'</span>, o), [<span class="hljs-property">@child</span>, <span class="hljs-property">@parent</span>]).compileToFragments o</pre></div></div>
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<h3 id="access">Access</h3>
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<p>A <code>.</code> access into a property of a value, or the <code>::</code> shorthand for
an access into the object’s prototype.</p>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.Access = <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">Access</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">Base</span></span>
<span class="hljs-attribute">constructor</span>: <span class="hljs-function"><span class="hljs-params">(<span class="hljs-property">@name</span>, tag)</span> -></span>
<span class="hljs-property">@name</span>.asKey = <span class="hljs-literal">yes</span>
<span class="hljs-property">@soak</span> = tag <span class="hljs-keyword">is</span> <span class="hljs-string">'soak'</span>
<span class="hljs-attribute">children</span>: [<span class="hljs-string">'name'</span>]
<span class="hljs-attribute">compileToFragments</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
name = <span class="hljs-property">@name</span>.compileToFragments o
<span class="hljs-keyword">if</span> IDENTIFIER.test fragmentsToText name
name.unshift <span class="hljs-property">@makeCode</span> <span class="hljs-string">"."</span>
<span class="hljs-keyword">else</span>
name.unshift <span class="hljs-property">@makeCode</span> <span class="hljs-string">"["</span>
name.push <span class="hljs-property">@makeCode</span> <span class="hljs-string">"]"</span>
name
<span class="hljs-attribute">isComplex</span>: NO</pre></div></div>
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<h3 id="index">Index</h3>
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<p>A <code>[ ... ]</code> indexed access into an array or object.</p>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.Index = <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">Index</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">Base</span></span>
<span class="hljs-attribute">constructor</span>: <span class="hljs-function"><span class="hljs-params">(<span class="hljs-property">@index</span>)</span> -></span>
<span class="hljs-attribute">children</span>: [<span class="hljs-string">'index'</span>]
<span class="hljs-attribute">compileToFragments</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
[].concat <span class="hljs-property">@makeCode</span>(<span class="hljs-string">"["</span>), <span class="hljs-property">@index</span>.compileToFragments(o, LEVEL_PAREN), <span class="hljs-property">@makeCode</span>(<span class="hljs-string">"]"</span>)
<span class="hljs-attribute">isComplex</span>:<span class="hljs-function"> -></span>
<span class="hljs-property">@index</span>.isComplex()</pre></div></div>
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<h3 id="range">Range</h3>
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<p>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.</p>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.Range = <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">Range</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">Base</span></span>
<span class="hljs-attribute">children</span>: [<span class="hljs-string">'from'</span>, <span class="hljs-string">'to'</span>]
<span class="hljs-attribute">constructor</span>: <span class="hljs-function"><span class="hljs-params">(<span class="hljs-property">@from</span>, <span class="hljs-property">@to</span>, tag)</span> -></span>
<span class="hljs-property">@exclusive</span> = tag <span class="hljs-keyword">is</span> <span class="hljs-string">'exclusive'</span>
<span class="hljs-property">@equals</span> = <span class="hljs-keyword">if</span> <span class="hljs-property">@exclusive</span> <span class="hljs-keyword">then</span> <span class="hljs-string">''</span> <span class="hljs-keyword">else</span> <span class="hljs-string">'='</span></pre></div></div>
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<p>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.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">compileVariables</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
o = merge o, <span class="hljs-attribute">top</span>: <span class="hljs-literal">true</span>
isComplex = del o, <span class="hljs-string">'isComplex'</span>
[<span class="hljs-property">@fromC</span>, <span class="hljs-property">@fromVar</span>] = <span class="hljs-property">@cacheToCodeFragments</span> <span class="hljs-property">@from</span>.cache o, LEVEL_LIST, isComplex
[<span class="hljs-property">@toC</span>, <span class="hljs-property">@toVar</span>] = <span class="hljs-property">@cacheToCodeFragments</span> <span class="hljs-property">@to</span>.cache o, LEVEL_LIST, isComplex
[<span class="hljs-property">@step</span>, <span class="hljs-property">@stepVar</span>] = <span class="hljs-property">@cacheToCodeFragments</span> step.cache o, LEVEL_LIST, isComplex <span class="hljs-keyword">if</span> step = del o, <span class="hljs-string">'step'</span>
[<span class="hljs-property">@fromNum</span>, <span class="hljs-property">@toNum</span>] = [<span class="hljs-property">@fromVar</span>.match(NUMBER), <span class="hljs-property">@toVar</span>.match(NUMBER)]
<span class="hljs-property">@stepNum</span> = <span class="hljs-property">@stepVar</span>.match(NUMBER) <span class="hljs-keyword">if</span> <span class="hljs-property">@stepVar</span></pre></div></div>
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<p>When compiled normally, the range returns the contents of the <em>for loop</em>
needed to iterate over the values in the range. Used by comprehensions.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">compileNode</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
<span class="hljs-property">@compileVariables</span> o <span class="hljs-keyword">unless</span> <span class="hljs-property">@fromVar</span>
<span class="hljs-keyword">return</span> <span class="hljs-property">@compileArray</span>(o) <span class="hljs-keyword">unless</span> o.index</pre></div></div>
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<p>Set up endpoints.</p>
</div>
<div class="content"><div class='highlight'><pre> known = <span class="hljs-property">@fromNum</span> <span class="hljs-keyword">and</span> <span class="hljs-property">@toNum</span>
idx = del o, <span class="hljs-string">'index'</span>
idxName = del o, <span class="hljs-string">'name'</span>
namedIndex = idxName <span class="hljs-keyword">and</span> idxName <span class="hljs-keyword">isnt</span> idx
varPart = <span class="hljs-string">"<span class="hljs-subst">#{idx}</span> = <span class="hljs-subst">#{<span class="hljs-property">@fromC</span>}</span>"</span>
varPart += <span class="hljs-string">", <span class="hljs-subst">#{<span class="hljs-property">@toC</span>}</span>"</span> <span class="hljs-keyword">if</span> <span class="hljs-property">@toC</span> <span class="hljs-keyword">isnt</span> <span class="hljs-property">@toVar</span>
varPart += <span class="hljs-string">", <span class="hljs-subst">#{<span class="hljs-property">@step</span>}</span>"</span> <span class="hljs-keyword">if</span> <span class="hljs-property">@step</span> <span class="hljs-keyword">isnt</span> <span class="hljs-property">@stepVar</span>
[lt, gt] = [<span class="hljs-string">"<span class="hljs-subst">#{idx}</span> <<span class="hljs-subst">#{<span class="hljs-property">@equals</span>}</span>"</span>, <span class="hljs-string">"<span class="hljs-subst">#{idx}</span> ><span class="hljs-subst">#{<span class="hljs-property">@equals</span>}</span>"</span>]</pre></div></div>
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<p>Generate the condition.</p>
</div>
<div class="content"><div class='highlight'><pre> condPart = <span class="hljs-keyword">if</span> <span class="hljs-property">@stepNum</span>
<span class="hljs-keyword">if</span> parseNum(<span class="hljs-property">@stepNum</span>[<span class="hljs-number">0</span>]) > <span class="hljs-number">0</span> <span class="hljs-keyword">then</span> <span class="hljs-string">"<span class="hljs-subst">#{lt}</span> <span class="hljs-subst">#{<span class="hljs-property">@toVar</span>}</span>"</span> <span class="hljs-keyword">else</span> <span class="hljs-string">"<span class="hljs-subst">#{gt}</span> <span class="hljs-subst">#{<span class="hljs-property">@toVar</span>}</span>"</span>
<span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> known
[from, to] = [parseNum(<span class="hljs-property">@fromNum</span>[<span class="hljs-number">0</span>]), parseNum(<span class="hljs-property">@toNum</span>[<span class="hljs-number">0</span>])]
<span class="hljs-keyword">if</span> from <= to <span class="hljs-keyword">then</span> <span class="hljs-string">"<span class="hljs-subst">#{lt}</span> <span class="hljs-subst">#{to}</span>"</span> <span class="hljs-keyword">else</span> <span class="hljs-string">"<span class="hljs-subst">#{gt}</span> <span class="hljs-subst">#{to}</span>"</span>
<span class="hljs-keyword">else</span>
cond = <span class="hljs-keyword">if</span> <span class="hljs-property">@stepVar</span> <span class="hljs-keyword">then</span> <span class="hljs-string">"<span class="hljs-subst">#{<span class="hljs-property">@stepVar</span>}</span> > 0"</span> <span class="hljs-keyword">else</span> <span class="hljs-string">"<span class="hljs-subst">#{<span class="hljs-property">@fromVar</span>}</span> <= <span class="hljs-subst">#{<span class="hljs-property">@toVar</span>}</span>"</span>
<span class="hljs-string">"<span class="hljs-subst">#{cond}</span> ? <span class="hljs-subst">#{lt}</span> <span class="hljs-subst">#{<span class="hljs-property">@toVar</span>}</span> : <span class="hljs-subst">#{gt}</span> <span class="hljs-subst">#{<span class="hljs-property">@toVar</span>}</span>"</span></pre></div></div>
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<p>Generate the step.</p>
</div>
<div class="content"><div class='highlight'><pre> stepPart = <span class="hljs-keyword">if</span> <span class="hljs-property">@stepVar</span>
<span class="hljs-string">"<span class="hljs-subst">#{idx}</span> += <span class="hljs-subst">#{<span class="hljs-property">@stepVar</span>}</span>"</span>
<span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> known
<span class="hljs-keyword">if</span> namedIndex
<span class="hljs-keyword">if</span> from <= to <span class="hljs-keyword">then</span> <span class="hljs-string">"++<span class="hljs-subst">#{idx}</span>"</span> <span class="hljs-keyword">else</span> <span class="hljs-string">"--<span class="hljs-subst">#{idx}</span>"</span>
<span class="hljs-keyword">else</span>
<span class="hljs-keyword">if</span> from <= to <span class="hljs-keyword">then</span> <span class="hljs-string">"<span class="hljs-subst">#{idx}</span>++"</span> <span class="hljs-keyword">else</span> <span class="hljs-string">"<span class="hljs-subst">#{idx}</span>--"</span>
<span class="hljs-keyword">else</span>
<span class="hljs-keyword">if</span> namedIndex
<span class="hljs-string">"<span class="hljs-subst">#{cond}</span> ? ++<span class="hljs-subst">#{idx}</span> : --<span class="hljs-subst">#{idx}</span>"</span>
<span class="hljs-keyword">else</span>
<span class="hljs-string">"<span class="hljs-subst">#{cond}</span> ? <span class="hljs-subst">#{idx}</span>++ : <span class="hljs-subst">#{idx}</span>--"</span>
varPart = <span class="hljs-string">"<span class="hljs-subst">#{idxName}</span> = <span class="hljs-subst">#{varPart}</span>"</span> <span class="hljs-keyword">if</span> namedIndex
stepPart = <span class="hljs-string">"<span class="hljs-subst">#{idxName}</span> = <span class="hljs-subst">#{stepPart}</span>"</span> <span class="hljs-keyword">if</span> namedIndex</pre></div></div>
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<p>The final loop body.</p>
</div>
<div class="content"><div class='highlight'><pre> [<span class="hljs-property">@makeCode</span> <span class="hljs-string">"<span class="hljs-subst">#{varPart}</span>; <span class="hljs-subst">#{condPart}</span>; <span class="hljs-subst">#{stepPart}</span>"</span>]</pre></div></div>
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<p>When used as a value, expand the range into the equivalent array.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">compileArray</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
<span class="hljs-keyword">if</span> <span class="hljs-property">@fromNum</span> <span class="hljs-keyword">and</span> <span class="hljs-property">@toNum</span> <span class="hljs-keyword">and</span> Math.abs(<span class="hljs-property">@fromNum</span> - <span class="hljs-property">@toNum</span>) <= <span class="hljs-number">20</span>
range = [+<span class="hljs-property">@fromNum</span>..+<span class="hljs-property">@toNum</span>]
range.pop() <span class="hljs-keyword">if</span> <span class="hljs-property">@exclusive</span>
<span class="hljs-keyword">return</span> [<span class="hljs-property">@makeCode</span> <span class="hljs-string">"[<span class="hljs-subst">#{ range.join(<span class="hljs-string">', '</span>) }</span>]"</span>]
idt = <span class="hljs-property">@tab</span> + TAB
i = o.scope.freeVariable <span class="hljs-string">'i'</span>, <span class="hljs-attribute">single</span>: <span class="hljs-literal">true</span>
result = o.scope.freeVariable <span class="hljs-string">'results'</span>
pre = <span class="hljs-string">"\n<span class="hljs-subst">#{idt}</span><span class="hljs-subst">#{result}</span> = [];"</span>
<span class="hljs-keyword">if</span> <span class="hljs-property">@fromNum</span> <span class="hljs-keyword">and</span> <span class="hljs-property">@toNum</span>
o.index = i
body = fragmentsToText <span class="hljs-property">@compileNode</span> o
<span class="hljs-keyword">else</span>
vars = <span class="hljs-string">"<span class="hljs-subst">#{i}</span> = <span class="hljs-subst">#{<span class="hljs-property">@fromC</span>}</span>"</span> + <span class="hljs-keyword">if</span> <span class="hljs-property">@toC</span> <span class="hljs-keyword">isnt</span> <span class="hljs-property">@toVar</span> <span class="hljs-keyword">then</span> <span class="hljs-string">", <span class="hljs-subst">#{<span class="hljs-property">@toC</span>}</span>"</span> <span class="hljs-keyword">else</span> <span class="hljs-string">''</span>
cond = <span class="hljs-string">"<span class="hljs-subst">#{<span class="hljs-property">@fromVar</span>}</span> <= <span class="hljs-subst">#{<span class="hljs-property">@toVar</span>}</span>"</span>
body = <span class="hljs-string">"var <span class="hljs-subst">#{vars}</span>; <span class="hljs-subst">#{cond}</span> ? <span class="hljs-subst">#{i}</span> <<span class="hljs-subst">#{<span class="hljs-property">@equals</span>}</span> <span class="hljs-subst">#{<span class="hljs-property">@toVar</span>}</span> : <span class="hljs-subst">#{i}</span> ><span class="hljs-subst">#{<span class="hljs-property">@equals</span>}</span> <span class="hljs-subst">#{<span class="hljs-property">@toVar</span>}</span>; <span class="hljs-subst">#{cond}</span> ? <span class="hljs-subst">#{i}</span>++ : <span class="hljs-subst">#{i}</span>--"</span>
post = <span class="hljs-string">"{ <span class="hljs-subst">#{result}</span>.push(<span class="hljs-subst">#{i}</span>); }\n<span class="hljs-subst">#{idt}</span>return <span class="hljs-subst">#{result}</span>;\n<span class="hljs-subst">#{o.indent}</span>"</span>
<span class="hljs-function"><span class="hljs-title">hasArgs</span> = <span class="hljs-params">(node)</span> -></span> node?.contains isLiteralArguments
args = <span class="hljs-string">', arguments'</span> <span class="hljs-keyword">if</span> hasArgs(<span class="hljs-property">@from</span>) <span class="hljs-keyword">or</span> hasArgs(<span class="hljs-property">@to</span>)
[<span class="hljs-property">@makeCode</span> <span class="hljs-string">"(function() {<span class="hljs-subst">#{pre}</span>\n<span class="hljs-subst">#{idt}</span>for (<span class="hljs-subst">#{body}</span>)<span class="hljs-subst">#{post}</span>}).apply(this<span class="hljs-subst">#{args ? <span class="hljs-string">''</span>}</span>)"</span>]</pre></div></div>
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<h3 id="slice">Slice</h3>
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<p>An array slice literal. Unlike JavaScript’s <code>Array#slice</code>, the second parameter
specifies the index of the end of the slice, just as the first parameter
is the index of the beginning.</p>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.Slice = <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">Slice</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">Base</span></span>
<span class="hljs-attribute">children</span>: [<span class="hljs-string">'range'</span>]
<span class="hljs-attribute">constructor</span>: <span class="hljs-function"><span class="hljs-params">(<span class="hljs-property">@range</span>)</span> -></span>
<span class="hljs-keyword">super</span>()</pre></div></div>
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<p>We have to be careful when trying to slice through the end of the array,
<code>9e9</code> is used because not all implementations respect <code>undefined</code> or <code>1/0</code>.
<code>9e9</code> should be safe because <code>9e9</code> > <code>2**32</code>, the max array length.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">compileNode</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
{to, from} = <span class="hljs-property">@range</span>
fromCompiled = from <span class="hljs-keyword">and</span> from.compileToFragments(o, LEVEL_PAREN) <span class="hljs-keyword">or</span> [<span class="hljs-property">@makeCode</span> <span class="hljs-string">'0'</span>]</pre></div></div>
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<p>TODO: jwalton - move this into the ‘if’?</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-keyword">if</span> to
compiled = to.compileToFragments o, LEVEL_PAREN
compiledText = fragmentsToText compiled
<span class="hljs-keyword">if</span> <span class="hljs-keyword">not</span> (<span class="hljs-keyword">not</span> <span class="hljs-property">@range</span>.exclusive <span class="hljs-keyword">and</span> +compiledText <span class="hljs-keyword">is</span> -<span class="hljs-number">1</span>)
toStr = <span class="hljs-string">', '</span> + <span class="hljs-keyword">if</span> <span class="hljs-property">@range</span>.exclusive
compiledText
<span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> SIMPLENUM.test compiledText
<span class="hljs-string">"<span class="hljs-subst">#{+compiledText + <span class="hljs-number">1</span>}</span>"</span>
<span class="hljs-keyword">else</span>
compiled = to.compileToFragments o, LEVEL_ACCESS
<span class="hljs-string">"+<span class="hljs-subst">#{fragmentsToText compiled}</span> + 1 || 9e9"</span>
[<span class="hljs-property">@makeCode</span> <span class="hljs-string">".slice(<span class="hljs-subst">#{ fragmentsToText fromCompiled }</span><span class="hljs-subst">#{ toStr <span class="hljs-keyword">or</span> <span class="hljs-string">''</span> }</span>)"</span>]</pre></div></div>
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<h3 id="obj">Obj</h3>
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<p>An object literal, nothing fancy.</p>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.Obj = <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">Obj</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">Base</span></span>
<span class="hljs-attribute">constructor</span>: <span class="hljs-function"><span class="hljs-params">(props, <span class="hljs-property">@generated</span> = <span class="hljs-literal">false</span>)</span> -></span>
<span class="hljs-property">@objects</span> = <span class="hljs-property">@properties</span> = props <span class="hljs-keyword">or</span> []
<span class="hljs-attribute">children</span>: [<span class="hljs-string">'properties'</span>]
<span class="hljs-attribute">compileNode</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
props = <span class="hljs-property">@properties</span>
<span class="hljs-keyword">if</span> <span class="hljs-property">@generated</span>
<span class="hljs-keyword">for</span> node <span class="hljs-keyword">in</span> props <span class="hljs-keyword">when</span> node <span class="hljs-keyword">instanceof</span> Value
node.error <span class="hljs-string">'cannot have an implicit value in an implicit object'</span>
<span class="hljs-keyword">break</span> <span class="hljs-keyword">for</span> prop, dynamicIndex <span class="hljs-keyword">in</span> props <span class="hljs-keyword">when</span> (prop.variable <span class="hljs-keyword">or</span> prop).base <span class="hljs-keyword">instanceof</span> Parens
hasDynamic = dynamicIndex < props.length
idt = o.indent += TAB
lastNoncom = <span class="hljs-property">@lastNonComment</span> <span class="hljs-property">@properties</span>
answer = []
<span class="hljs-keyword">if</span> hasDynamic
oref = o.scope.freeVariable <span class="hljs-string">'obj'</span>
answer.push <span class="hljs-property">@makeCode</span> <span class="hljs-string">"(\n<span class="hljs-subst">#{idt}</span><span class="hljs-subst">#{oref}</span> = "</span>
answer.push <span class="hljs-property">@makeCode</span> <span class="hljs-string">"{<span class="hljs-subst">#{<span class="hljs-keyword">if</span> props.length <span class="hljs-keyword">is</span> <span class="hljs-number">0</span> <span class="hljs-keyword">or</span> dynamicIndex <span class="hljs-keyword">is</span> <span class="hljs-number">0</span> <span class="hljs-keyword">then</span> <span class="hljs-string">'}'</span> <span class="hljs-keyword">else</span> <span class="hljs-string">'\n'</span>}</span>"</span>
<span class="hljs-keyword">for</span> prop, i <span class="hljs-keyword">in</span> props
<span class="hljs-keyword">if</span> i <span class="hljs-keyword">is</span> dynamicIndex
answer.push <span class="hljs-property">@makeCode</span> <span class="hljs-string">"\n<span class="hljs-subst">#{idt}</span>}"</span> <span class="hljs-keyword">unless</span> i <span class="hljs-keyword">is</span> <span class="hljs-number">0</span>
answer.push <span class="hljs-property">@makeCode</span> <span class="hljs-string">',\n'</span>
join = <span class="hljs-keyword">if</span> i <span class="hljs-keyword">is</span> props.length - <span class="hljs-number">1</span> <span class="hljs-keyword">or</span> i <span class="hljs-keyword">is</span> dynamicIndex - <span class="hljs-number">1</span>
<span class="hljs-string">''</span>
<span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> prop <span class="hljs-keyword">is</span> lastNoncom <span class="hljs-keyword">or</span> prop <span class="hljs-keyword">instanceof</span> Comment
<span class="hljs-string">'\n'</span>
<span class="hljs-keyword">else</span>
<span class="hljs-string">',\n'</span>
indent = <span class="hljs-keyword">if</span> prop <span class="hljs-keyword">instanceof</span> Comment <span class="hljs-keyword">then</span> <span class="hljs-string">''</span> <span class="hljs-keyword">else</span> idt
indent += TAB <span class="hljs-keyword">if</span> hasDynamic <span class="hljs-keyword">and</span> i < dynamicIndex
<span class="hljs-keyword">if</span> prop <span class="hljs-keyword">instanceof</span> Assign
<span class="hljs-keyword">if</span> prop.context <span class="hljs-keyword">isnt</span> <span class="hljs-string">'object'</span>
prop.operatorToken.error <span class="hljs-string">"unexpected <span class="hljs-subst">#{prop.operatorToken.value}</span>"</span>
<span class="hljs-keyword">if</span> prop.variable <span class="hljs-keyword">instanceof</span> Value <span class="hljs-keyword">and</span> prop.variable.hasProperties()
prop.variable.error <span class="hljs-string">'invalid object key'</span>
<span class="hljs-keyword">if</span> prop <span class="hljs-keyword">instanceof</span> Value <span class="hljs-keyword">and</span> prop.<span class="hljs-keyword">this</span>
prop = <span class="hljs-keyword">new</span> Assign prop.properties[<span class="hljs-number">0</span>].name, prop, <span class="hljs-string">'object'</span>
<span class="hljs-keyword">if</span> prop <span class="hljs-keyword">not</span> <span class="hljs-keyword">instanceof</span> Comment
<span class="hljs-keyword">if</span> i < dynamicIndex
<span class="hljs-keyword">if</span> prop <span class="hljs-keyword">not</span> <span class="hljs-keyword">instanceof</span> Assign
prop = <span class="hljs-keyword">new</span> Assign prop, prop, <span class="hljs-string">'object'</span>
(prop.variable.base <span class="hljs-keyword">or</span> prop.variable).asKey = <span class="hljs-literal">yes</span>
<span class="hljs-keyword">else</span>
<span class="hljs-keyword">if</span> prop <span class="hljs-keyword">instanceof</span> Assign
key = prop.variable
value = prop.value
<span class="hljs-keyword">else</span>
[key, value] = prop.base.cache o
prop = <span class="hljs-keyword">new</span> Assign (<span class="hljs-keyword">new</span> Value (<span class="hljs-keyword">new</span> Literal oref), [<span class="hljs-keyword">new</span> Access key]), value
<span class="hljs-keyword">if</span> indent <span class="hljs-keyword">then</span> answer.push <span class="hljs-property">@makeCode</span> indent
answer.push prop.compileToFragments(o, LEVEL_TOP)...
<span class="hljs-keyword">if</span> join <span class="hljs-keyword">then</span> answer.push <span class="hljs-property">@makeCode</span> join
<span class="hljs-keyword">if</span> hasDynamic
answer.push <span class="hljs-property">@makeCode</span> <span class="hljs-string">",\n<span class="hljs-subst">#{idt}</span><span class="hljs-subst">#{oref}</span>\n<span class="hljs-subst">#{<span class="hljs-property">@tab</span>}</span>)"</span>
<span class="hljs-keyword">else</span>
answer.push <span class="hljs-property">@makeCode</span> <span class="hljs-string">"\n<span class="hljs-subst">#{<span class="hljs-property">@tab</span>}</span>}"</span> <span class="hljs-keyword">unless</span> props.length <span class="hljs-keyword">is</span> <span class="hljs-number">0</span>
<span class="hljs-keyword">if</span> <span class="hljs-property">@front</span> <span class="hljs-keyword">and</span> <span class="hljs-keyword">not</span> hasDynamic <span class="hljs-keyword">then</span> <span class="hljs-property">@wrapInBraces</span> answer <span class="hljs-keyword">else</span> answer
<span class="hljs-attribute">assigns</span>: <span class="hljs-function"><span class="hljs-params">(name)</span> -></span>
<span class="hljs-keyword">for</span> prop <span class="hljs-keyword">in</span> <span class="hljs-property">@properties</span> <span class="hljs-keyword">when</span> prop.assigns name <span class="hljs-keyword">then</span> <span class="hljs-keyword">return</span> <span class="hljs-literal">yes</span>
<span class="hljs-literal">no</span></pre></div></div>
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<h3 id="arr">Arr</h3>
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<p>An array literal.</p>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.Arr = <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">Arr</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">Base</span></span>
<span class="hljs-attribute">constructor</span>: <span class="hljs-function"><span class="hljs-params">(objs)</span> -></span>
<span class="hljs-property">@objects</span> = objs <span class="hljs-keyword">or</span> []
<span class="hljs-attribute">children</span>: [<span class="hljs-string">'objects'</span>]
<span class="hljs-attribute">compileNode</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
<span class="hljs-keyword">return</span> [<span class="hljs-property">@makeCode</span> <span class="hljs-string">'[]'</span>] <span class="hljs-keyword">unless</span> <span class="hljs-property">@objects</span>.length
o.indent += TAB
answer = Splat.compileSplattedArray o, <span class="hljs-property">@objects</span>
<span class="hljs-keyword">return</span> answer <span class="hljs-keyword">if</span> answer.length
answer = []
compiledObjs = (obj.compileToFragments o, LEVEL_LIST <span class="hljs-keyword">for</span> obj <span class="hljs-keyword">in</span> <span class="hljs-property">@objects</span>)
<span class="hljs-keyword">for</span> fragments, index <span class="hljs-keyword">in</span> compiledObjs
<span class="hljs-keyword">if</span> index
answer.push <span class="hljs-property">@makeCode</span> <span class="hljs-string">", "</span>
answer.push fragments...
<span class="hljs-keyword">if</span> fragmentsToText(answer).indexOf(<span class="hljs-string">'\n'</span>) >= <span class="hljs-number">0</span>
answer.unshift <span class="hljs-property">@makeCode</span> <span class="hljs-string">"[\n<span class="hljs-subst">#{o.indent}</span>"</span>
answer.push <span class="hljs-property">@makeCode</span> <span class="hljs-string">"\n<span class="hljs-subst">#{<span class="hljs-property">@tab</span>}</span>]"</span>
<span class="hljs-keyword">else</span>
answer.unshift <span class="hljs-property">@makeCode</span> <span class="hljs-string">"["</span>
answer.push <span class="hljs-property">@makeCode</span> <span class="hljs-string">"]"</span>
answer
<span class="hljs-attribute">assigns</span>: <span class="hljs-function"><span class="hljs-params">(name)</span> -></span>
<span class="hljs-keyword">for</span> obj <span class="hljs-keyword">in</span> <span class="hljs-property">@objects</span> <span class="hljs-keyword">when</span> obj.assigns name <span class="hljs-keyword">then</span> <span class="hljs-keyword">return</span> <span class="hljs-literal">yes</span>
<span class="hljs-literal">no</span></pre></div></div>
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<h3 id="class">Class</h3>
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<p>The CoffeeScript class definition.
Initialize a <strong>Class</strong> with its name, an optional superclass, and a
list of prototype property assignments.</p>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.Class = <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">Class</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">Base</span></span>
<span class="hljs-attribute">constructor</span>: <span class="hljs-function"><span class="hljs-params">(<span class="hljs-property">@variable</span>, <span class="hljs-property">@parent</span>, <span class="hljs-property">@body</span> = <span class="hljs-keyword">new</span> Block)</span> -></span>
<span class="hljs-property">@boundFuncs</span> = []
<span class="hljs-property">@body</span>.classBody = <span class="hljs-literal">yes</span>
<span class="hljs-attribute">children</span>: [<span class="hljs-string">'variable'</span>, <span class="hljs-string">'parent'</span>, <span class="hljs-string">'body'</span>]</pre></div></div>
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<p>Figure out the appropriate name for the constructor function of this class.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">determineName</span>:<span class="hljs-function"> -></span>
<span class="hljs-keyword">return</span> <span class="hljs-literal">null</span> <span class="hljs-keyword">unless</span> <span class="hljs-property">@variable</span>
[..., tail] = <span class="hljs-property">@variable</span>.properties
decl = <span class="hljs-keyword">if</span> tail
tail <span class="hljs-keyword">instanceof</span> Access <span class="hljs-keyword">and</span> tail.name.value
<span class="hljs-keyword">else</span>
<span class="hljs-property">@variable</span>.base.value
<span class="hljs-keyword">if</span> decl <span class="hljs-keyword">in</span> STRICT_PROSCRIBED
<span class="hljs-property">@variable</span>.error <span class="hljs-string">"class variable name may not be <span class="hljs-subst">#{decl}</span>"</span>
decl <span class="hljs-keyword">and</span>= IDENTIFIER.test(decl) <span class="hljs-keyword">and</span> decl</pre></div></div>
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<p>For all <code>this</code>-references and bound functions in the class definition,
<code>this</code> is the Class being constructed.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">setContext</span>: <span class="hljs-function"><span class="hljs-params">(name)</span> -></span>
<span class="hljs-property">@body</span>.traverseChildren <span class="hljs-literal">false</span>, <span class="hljs-function"><span class="hljs-params">(node)</span> -></span>
<span class="hljs-keyword">return</span> <span class="hljs-literal">false</span> <span class="hljs-keyword">if</span> node.classBody
<span class="hljs-keyword">if</span> node <span class="hljs-keyword">instanceof</span> Literal <span class="hljs-keyword">and</span> node.value <span class="hljs-keyword">is</span> <span class="hljs-string">'this'</span>
node.value = name
<span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> node <span class="hljs-keyword">instanceof</span> Code
node.context = name <span class="hljs-keyword">if</span> node.bound</pre></div></div>
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<p>Ensure that all functions bound to the instance are proxied in the
constructor.</p>
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<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">addBoundFunctions</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
<span class="hljs-keyword">for</span> bvar <span class="hljs-keyword">in</span> <span class="hljs-property">@boundFuncs</span>
lhs = (<span class="hljs-keyword">new</span> Value (<span class="hljs-keyword">new</span> Literal <span class="hljs-string">"this"</span>), [<span class="hljs-keyword">new</span> Access bvar]).compile o
<span class="hljs-property">@ctor</span>.body.unshift <span class="hljs-keyword">new</span> Literal <span class="hljs-string">"<span class="hljs-subst">#{lhs}</span> = <span class="hljs-subst">#{utility <span class="hljs-string">'bind'</span>, o}</span>(<span class="hljs-subst">#{lhs}</span>, this)"</span>
<span class="hljs-keyword">return</span></pre></div></div>
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<p>Merge the properties from a top-level object as prototypal properties
on the class.</p>
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<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">addProperties</span>: <span class="hljs-function"><span class="hljs-params">(node, name, o)</span> -></span>
props = node.base.properties[..]
exprs = <span class="hljs-keyword">while</span> assign = props.shift()
<span class="hljs-keyword">if</span> assign <span class="hljs-keyword">instanceof</span> Assign
base = assign.variable.base
<span class="hljs-keyword">delete</span> assign.context
func = assign.value
<span class="hljs-keyword">if</span> base.value <span class="hljs-keyword">is</span> <span class="hljs-string">'constructor'</span>
<span class="hljs-keyword">if</span> <span class="hljs-property">@ctor</span>
assign.error <span class="hljs-string">'cannot define more than one constructor in a class'</span>
<span class="hljs-keyword">if</span> func.bound
assign.error <span class="hljs-string">'cannot define a constructor as a bound function'</span>
<span class="hljs-keyword">if</span> func <span class="hljs-keyword">instanceof</span> Code
assign = <span class="hljs-property">@ctor</span> = func
<span class="hljs-keyword">else</span>
<span class="hljs-property">@externalCtor</span> = o.classScope.freeVariable <span class="hljs-string">'class'</span>
assign = <span class="hljs-keyword">new</span> Assign <span class="hljs-keyword">new</span> Literal(<span class="hljs-property">@externalCtor</span>), func
<span class="hljs-keyword">else</span>
<span class="hljs-keyword">if</span> assign.variable.<span class="hljs-keyword">this</span>
func.static = <span class="hljs-literal">yes</span>
<span class="hljs-keyword">else</span>
acc = <span class="hljs-keyword">if</span> base.isComplex() <span class="hljs-keyword">then</span> <span class="hljs-keyword">new</span> Index base <span class="hljs-keyword">else</span> <span class="hljs-keyword">new</span> Access base
assign.variable = <span class="hljs-keyword">new</span> Value(<span class="hljs-keyword">new</span> Literal(name), [(<span class="hljs-keyword">new</span> Access <span class="hljs-keyword">new</span> Literal <span class="hljs-string">'prototype'</span>), acc])
<span class="hljs-keyword">if</span> func <span class="hljs-keyword">instanceof</span> Code <span class="hljs-keyword">and</span> func.bound
<span class="hljs-property">@boundFuncs</span>.push base
func.bound = <span class="hljs-literal">no</span>
assign
compact exprs</pre></div></div>
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<p>Walk the body of the class, looking for prototype properties to be converted
and tagging static assignments.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">walkBody</span>: <span class="hljs-function"><span class="hljs-params">(name, o)</span> -></span>
<span class="hljs-property">@traverseChildren</span> <span class="hljs-literal">false</span>, <span class="hljs-function"><span class="hljs-params">(child)</span> =></span>
cont = <span class="hljs-literal">true</span>
<span class="hljs-keyword">return</span> <span class="hljs-literal">false</span> <span class="hljs-keyword">if</span> child <span class="hljs-keyword">instanceof</span> Class
<span class="hljs-keyword">if</span> child <span class="hljs-keyword">instanceof</span> Block
<span class="hljs-keyword">for</span> node, i <span class="hljs-keyword">in</span> exps = child.expressions
<span class="hljs-keyword">if</span> node <span class="hljs-keyword">instanceof</span> Assign <span class="hljs-keyword">and</span> node.variable.looksStatic name
node.value.static = <span class="hljs-literal">yes</span>
<span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> node <span class="hljs-keyword">instanceof</span> Value <span class="hljs-keyword">and</span> node.isObject(<span class="hljs-literal">true</span>)
cont = <span class="hljs-literal">false</span>
exps[i] = <span class="hljs-property">@addProperties</span> node, name, o
child.expressions = exps = flatten exps
cont <span class="hljs-keyword">and</span> child <span class="hljs-keyword">not</span> <span class="hljs-keyword">instanceof</span> Class</pre></div></div>
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<p><code>use strict</code> (and other directives) must be the first expression statement(s)
of a function body. This method ensures the prologue is correctly positioned
above the <code>constructor</code>.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">hoistDirectivePrologue</span>:<span class="hljs-function"> -></span>
index = <span class="hljs-number">0</span>
{expressions} = <span class="hljs-property">@body</span>
++index <span class="hljs-keyword">while</span> (node = expressions[index]) <span class="hljs-keyword">and</span> node <span class="hljs-keyword">instanceof</span> Comment <span class="hljs-keyword">or</span>
node <span class="hljs-keyword">instanceof</span> Value <span class="hljs-keyword">and</span> node.isString()
<span class="hljs-property">@directives</span> = expressions.splice <span class="hljs-number">0</span>, index</pre></div></div>
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<p>Make sure that a constructor is defined for the class, and properly
configured.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">ensureConstructor</span>: <span class="hljs-function"><span class="hljs-params">(name)</span> -></span>
<span class="hljs-keyword">if</span> <span class="hljs-keyword">not</span> <span class="hljs-property">@ctor</span>
<span class="hljs-property">@ctor</span> = <span class="hljs-keyword">new</span> Code
<span class="hljs-keyword">if</span> <span class="hljs-property">@externalCtor</span>
<span class="hljs-property">@ctor</span>.body.push <span class="hljs-keyword">new</span> Literal <span class="hljs-string">"<span class="hljs-subst">#{<span class="hljs-property">@externalCtor</span>}</span>.apply(this, arguments)"</span>
<span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> <span class="hljs-property">@parent</span>
<span class="hljs-property">@ctor</span>.body.push <span class="hljs-keyword">new</span> Literal <span class="hljs-string">"<span class="hljs-subst">#{name}</span>.__super__.constructor.apply(this, arguments)"</span>
<span class="hljs-property">@ctor</span>.body.makeReturn()
<span class="hljs-property">@body</span>.expressions.unshift <span class="hljs-property">@ctor</span>
<span class="hljs-property">@ctor</span>.ctor = <span class="hljs-property">@ctor</span>.name = name
<span class="hljs-property">@ctor</span>.klass = <span class="hljs-literal">null</span>
<span class="hljs-property">@ctor</span>.noReturn = <span class="hljs-literal">yes</span></pre></div></div>
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<p>Instead of generating the JavaScript string directly, we build up the
equivalent syntax tree and compile that, in pieces. You can see the
constructor, property assignments, and inheritance getting built out below.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">compileNode</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
<span class="hljs-keyword">if</span> jumpNode = <span class="hljs-property">@body</span>.jumps()
jumpNode.error <span class="hljs-string">'Class bodies cannot contain pure statements'</span>
<span class="hljs-keyword">if</span> argumentsNode = <span class="hljs-property">@body</span>.contains isLiteralArguments
argumentsNode.error <span class="hljs-string">"Class bodies shouldn't reference arguments"</span>
name = <span class="hljs-property">@determineName</span>() <span class="hljs-keyword">or</span> <span class="hljs-string">'_Class'</span>
name = <span class="hljs-string">"_<span class="hljs-subst">#{name}</span>"</span> <span class="hljs-keyword">if</span> name.reserved
lname = <span class="hljs-keyword">new</span> Literal name
func = <span class="hljs-keyword">new</span> Code [], Block.wrap [<span class="hljs-property">@body</span>]
args = []
o.classScope = func.makeScope o.scope
<span class="hljs-property">@hoistDirectivePrologue</span>()
<span class="hljs-property">@setContext</span> name
<span class="hljs-property">@walkBody</span> name, o
<span class="hljs-property">@ensureConstructor</span> name
<span class="hljs-property">@addBoundFunctions</span> o
<span class="hljs-property">@body</span>.spaced = <span class="hljs-literal">yes</span>
<span class="hljs-property">@body</span>.expressions.push lname
<span class="hljs-keyword">if</span> <span class="hljs-property">@parent</span>
superClass = <span class="hljs-keyword">new</span> Literal o.classScope.freeVariable <span class="hljs-string">'superClass'</span>, <span class="hljs-attribute">reserve</span>: <span class="hljs-literal">no</span>
<span class="hljs-property">@body</span>.expressions.unshift <span class="hljs-keyword">new</span> Extends lname, superClass
func.params.push <span class="hljs-keyword">new</span> Param superClass
args.push <span class="hljs-property">@parent</span>
<span class="hljs-property">@body</span>.expressions.unshift <span class="hljs-property">@directives</span>...
klass = <span class="hljs-keyword">new</span> Parens <span class="hljs-keyword">new</span> Call func, args
klass = <span class="hljs-keyword">new</span> Assign <span class="hljs-property">@variable</span>, klass <span class="hljs-keyword">if</span> <span class="hljs-property">@variable</span>
klass.compileToFragments o</pre></div></div>
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<h3 id="assign">Assign</h3>
</div>
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<p>The <strong>Assign</strong> is used to assign a local variable to value, or to set the
property of an object — including within object literals.</p>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.Assign = <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">Assign</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">Base</span></span>
<span class="hljs-attribute">constructor</span>: <span class="hljs-function"><span class="hljs-params">(<span class="hljs-property">@variable</span>, <span class="hljs-property">@value</span>, <span class="hljs-property">@context</span>, options = {})</span> -></span>
{<span class="hljs-property">@param</span>, <span class="hljs-property">@subpattern</span>, <span class="hljs-property">@operatorToken</span>} = options
forbidden = (name = <span class="hljs-property">@variable</span>.unwrapAll().value) <span class="hljs-keyword">in</span> STRICT_PROSCRIBED
<span class="hljs-keyword">if</span> forbidden <span class="hljs-keyword">and</span> <span class="hljs-property">@context</span> <span class="hljs-keyword">isnt</span> <span class="hljs-string">'object'</span>
<span class="hljs-property">@variable</span>.error <span class="hljs-string">"variable name may not be \"<span class="hljs-subst">#{name}</span>\""</span>
<span class="hljs-attribute">children</span>: [<span class="hljs-string">'variable'</span>, <span class="hljs-string">'value'</span>]
<span class="hljs-attribute">isStatement</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
o?.level <span class="hljs-keyword">is</span> LEVEL_TOP <span class="hljs-keyword">and</span> <span class="hljs-property">@context</span>? <span class="hljs-keyword">and</span> <span class="hljs-string">"?"</span> <span class="hljs-keyword">in</span> <span class="hljs-property">@context</span>
<span class="hljs-attribute">assigns</span>: <span class="hljs-function"><span class="hljs-params">(name)</span> -></span>
@[<span class="hljs-keyword">if</span> <span class="hljs-property">@context</span> <span class="hljs-keyword">is</span> <span class="hljs-string">'object'</span> <span class="hljs-keyword">then</span> <span class="hljs-string">'value'</span> <span class="hljs-keyword">else</span> <span class="hljs-string">'variable'</span>].assigns name
<span class="hljs-attribute">unfoldSoak</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
unfoldSoak o, <span class="hljs-keyword">this</span>, <span class="hljs-string">'variable'</span></pre></div></div>
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<p>Compile an assignment, delegating to <code>compilePatternMatch</code> or
<code>compileSplice</code> if appropriate. Keep track of the name of the base object
we’ve been assigned to, for correct internal references. If the variable
has not been seen yet within the current scope, declare it.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">compileNode</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
<span class="hljs-keyword">if</span> isValue = <span class="hljs-property">@variable</span> <span class="hljs-keyword">instanceof</span> Value
<span class="hljs-keyword">return</span> <span class="hljs-property">@compilePatternMatch</span> o <span class="hljs-keyword">if</span> <span class="hljs-property">@variable</span>.isArray() <span class="hljs-keyword">or</span> <span class="hljs-property">@variable</span>.isObject()
<span class="hljs-keyword">return</span> <span class="hljs-property">@compileSplice</span> o <span class="hljs-keyword">if</span> <span class="hljs-property">@variable</span>.isSplice()
<span class="hljs-keyword">return</span> <span class="hljs-property">@compileConditional</span> o <span class="hljs-keyword">if</span> <span class="hljs-property">@context</span> <span class="hljs-keyword">in</span> [<span class="hljs-string">'||='</span>, <span class="hljs-string">'&&='</span>, <span class="hljs-string">'?='</span>]
<span class="hljs-keyword">return</span> <span class="hljs-property">@compileSpecialMath</span> o <span class="hljs-keyword">if</span> <span class="hljs-property">@context</span> <span class="hljs-keyword">in</span> [<span class="hljs-string">'**='</span>, <span class="hljs-string">'//='</span>, <span class="hljs-string">'%%='</span>]
<span class="hljs-keyword">if</span> <span class="hljs-property">@value</span> <span class="hljs-keyword">instanceof</span> Code
<span class="hljs-keyword">if</span> <span class="hljs-property">@value</span>.static
<span class="hljs-property">@value</span>.klass = <span class="hljs-property">@variable</span>.base
<span class="hljs-property">@value</span>.name = <span class="hljs-property">@variable</span>.properties[<span class="hljs-number">0</span>]
<span class="hljs-property">@value</span>.variable = <span class="hljs-property">@variable</span>
<span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> <span class="hljs-property">@variable</span>.properties?.length >= <span class="hljs-number">2</span>
[properties..., prototype, name] = <span class="hljs-property">@variable</span>.properties
<span class="hljs-keyword">if</span> prototype.name?.value <span class="hljs-keyword">is</span> <span class="hljs-string">'prototype'</span>
<span class="hljs-property">@value</span>.klass = <span class="hljs-keyword">new</span> Value <span class="hljs-property">@variable</span>.base, properties
<span class="hljs-property">@value</span>.name = name
<span class="hljs-property">@value</span>.variable = <span class="hljs-property">@variable</span>
<span class="hljs-keyword">unless</span> <span class="hljs-property">@context</span>
varBase = <span class="hljs-property">@variable</span>.unwrapAll()
<span class="hljs-keyword">unless</span> varBase.isAssignable()
<span class="hljs-property">@variable</span>.error <span class="hljs-string">"\"<span class="hljs-subst">#{<span class="hljs-property">@variable</span>.compile o}</span>\" cannot be assigned"</span>
<span class="hljs-keyword">unless</span> varBase.hasProperties?()
<span class="hljs-keyword">if</span> <span class="hljs-property">@param</span>
o.scope.add varBase.value, <span class="hljs-string">'var'</span>
<span class="hljs-keyword">else</span>
o.scope.find varBase.value
val = <span class="hljs-property">@value</span>.compileToFragments o, LEVEL_LIST
<span class="hljs-property">@variable</span>.front = <span class="hljs-literal">true</span> <span class="hljs-keyword">if</span> isValue <span class="hljs-keyword">and</span> <span class="hljs-property">@variable</span>.base <span class="hljs-keyword">instanceof</span> Obj
compiledName = <span class="hljs-property">@variable</span>.compileToFragments o, LEVEL_LIST
<span class="hljs-keyword">return</span> (compiledName.concat <span class="hljs-property">@makeCode</span>(<span class="hljs-string">": "</span>), val) <span class="hljs-keyword">if</span> <span class="hljs-property">@context</span> <span class="hljs-keyword">is</span> <span class="hljs-string">'object'</span>
answer = compiledName.concat <span class="hljs-property">@makeCode</span>(<span class="hljs-string">" <span class="hljs-subst">#{ <span class="hljs-property">@context</span> <span class="hljs-keyword">or</span> <span class="hljs-string">'='</span> }</span> "</span>), val
<span class="hljs-keyword">if</span> o.level <= LEVEL_LIST <span class="hljs-keyword">then</span> answer <span class="hljs-keyword">else</span> <span class="hljs-property">@wrapInBraces</span> answer</pre></div></div>
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<p>Brief implementation of recursive pattern matching, when assigning array or
object literals to a value. Peeks at their properties to assign inner names.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">compilePatternMatch</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
top = o.level <span class="hljs-keyword">is</span> LEVEL_TOP
{value} = <span class="hljs-keyword">this</span>
{objects} = <span class="hljs-property">@variable</span>.base
<span class="hljs-keyword">unless</span> olen = objects.length
code = value.compileToFragments o
<span class="hljs-keyword">return</span> <span class="hljs-keyword">if</span> o.level >= LEVEL_OP <span class="hljs-keyword">then</span> <span class="hljs-property">@wrapInBraces</span> code <span class="hljs-keyword">else</span> code
[obj] = objects
<span class="hljs-keyword">if</span> olen <span class="hljs-keyword">is</span> <span class="hljs-number">1</span> <span class="hljs-keyword">and</span> obj <span class="hljs-keyword">instanceof</span> Expansion
obj.error <span class="hljs-string">'Destructuring assignment has no target'</span>
isObject = <span class="hljs-property">@variable</span>.isObject()
<span class="hljs-keyword">if</span> top <span class="hljs-keyword">and</span> olen <span class="hljs-keyword">is</span> <span class="hljs-number">1</span> <span class="hljs-keyword">and</span> obj <span class="hljs-keyword">not</span> <span class="hljs-keyword">instanceof</span> Splat</pre></div></div>
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<p>Pick the property straight off the value when there’s just one to pick
(no need to cache the value into a variable).</p>
</div>
<div class="content"><div class='highlight'><pre> defaultValue = <span class="hljs-literal">null</span>
<span class="hljs-keyword">if</span> obj <span class="hljs-keyword">instanceof</span> Assign <span class="hljs-keyword">and</span> obj.context <span class="hljs-keyword">is</span> <span class="hljs-string">'object'</span></pre></div></div>
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<p>A regular object pattern-match.</p>
</div>
<div class="content"><div class='highlight'><pre> {<span class="hljs-attribute">variable</span>: {<span class="hljs-attribute">base</span>: idx}, <span class="hljs-attribute">value</span>: obj} = obj
<span class="hljs-keyword">if</span> obj <span class="hljs-keyword">instanceof</span> Assign
defaultValue = obj.value
obj = obj.variable
<span class="hljs-keyword">else</span>
<span class="hljs-keyword">if</span> obj <span class="hljs-keyword">instanceof</span> Assign
defaultValue = obj.value
obj = obj.variable
idx = <span class="hljs-keyword">if</span> isObject</pre></div></div>
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<p>A shorthand <code>{a, b, @c} = val</code> pattern-match.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-keyword">if</span> obj.<span class="hljs-keyword">this</span> <span class="hljs-keyword">then</span> obj.properties[<span class="hljs-number">0</span>].name <span class="hljs-keyword">else</span> obj
<span class="hljs-keyword">else</span></pre></div></div>
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<p>A regular array pattern-match.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-keyword">new</span> Literal <span class="hljs-number">0</span>
acc = IDENTIFIER.test idx.unwrap().value
value = <span class="hljs-keyword">new</span> Value value
value.properties.push <span class="hljs-keyword">new</span> (<span class="hljs-keyword">if</span> acc <span class="hljs-keyword">then</span> Access <span class="hljs-keyword">else</span> Index) idx
<span class="hljs-keyword">if</span> obj.unwrap().value <span class="hljs-keyword">in</span> RESERVED
obj.error <span class="hljs-string">"assignment to a reserved word: <span class="hljs-subst">#{obj.compile o}</span>"</span>
value = <span class="hljs-keyword">new</span> Op <span class="hljs-string">'?'</span>, value, defaultValue <span class="hljs-keyword">if</span> defaultValue
<span class="hljs-keyword">return</span> <span class="hljs-keyword">new</span> Assign(obj, value, <span class="hljs-literal">null</span>, <span class="hljs-attribute">param</span>: <span class="hljs-property">@param</span>).compileToFragments o, LEVEL_TOP
vvar = value.compileToFragments o, LEVEL_LIST
vvarText = fragmentsToText vvar
assigns = []
expandedIdx = <span class="hljs-literal">false</span></pre></div></div>
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<p>Make vvar into a simple variable if it isn’t already.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-keyword">if</span> <span class="hljs-keyword">not</span> IDENTIFIER.test(vvarText) <span class="hljs-keyword">or</span> <span class="hljs-property">@variable</span>.assigns(vvarText)
assigns.push [<span class="hljs-property">@makeCode</span>(<span class="hljs-string">"<span class="hljs-subst">#{ ref = o.scope.freeVariable <span class="hljs-string">'ref'</span> }</span> = "</span>), vvar...]
vvar = [<span class="hljs-property">@makeCode</span> ref]
vvarText = ref
<span class="hljs-keyword">for</span> obj, i <span class="hljs-keyword">in</span> objects
idx = i
<span class="hljs-keyword">if</span> <span class="hljs-keyword">not</span> expandedIdx <span class="hljs-keyword">and</span> obj <span class="hljs-keyword">instanceof</span> Splat
name = obj.name.unwrap().value
obj = obj.unwrap()
val = <span class="hljs-string">"<span class="hljs-subst">#{olen}</span> <= <span class="hljs-subst">#{vvarText}</span>.length ? <span class="hljs-subst">#{ utility <span class="hljs-string">'slice'</span>, o }</span>.call(<span class="hljs-subst">#{vvarText}</span>, <span class="hljs-subst">#{i}</span>"</span>
<span class="hljs-keyword">if</span> rest = olen - i - <span class="hljs-number">1</span>
ivar = o.scope.freeVariable <span class="hljs-string">'i'</span>, <span class="hljs-attribute">single</span>: <span class="hljs-literal">true</span>
val += <span class="hljs-string">", <span class="hljs-subst">#{ivar}</span> = <span class="hljs-subst">#{vvarText}</span>.length - <span class="hljs-subst">#{rest}</span>) : (<span class="hljs-subst">#{ivar}</span> = <span class="hljs-subst">#{i}</span>, [])"</span>
<span class="hljs-keyword">else</span>
val += <span class="hljs-string">") : []"</span>
val = <span class="hljs-keyword">new</span> Literal val
expandedIdx = <span class="hljs-string">"<span class="hljs-subst">#{ivar}</span>++"</span>
<span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> <span class="hljs-keyword">not</span> expandedIdx <span class="hljs-keyword">and</span> obj <span class="hljs-keyword">instanceof</span> Expansion
<span class="hljs-keyword">if</span> rest = olen - i - <span class="hljs-number">1</span>
<span class="hljs-keyword">if</span> rest <span class="hljs-keyword">is</span> <span class="hljs-number">1</span>
expandedIdx = <span class="hljs-string">"<span class="hljs-subst">#{vvarText}</span>.length - 1"</span>
<span class="hljs-keyword">else</span>
ivar = o.scope.freeVariable <span class="hljs-string">'i'</span>, <span class="hljs-attribute">single</span>: <span class="hljs-literal">true</span>
val = <span class="hljs-keyword">new</span> Literal <span class="hljs-string">"<span class="hljs-subst">#{ivar}</span> = <span class="hljs-subst">#{vvarText}</span>.length - <span class="hljs-subst">#{rest}</span>"</span>
expandedIdx = <span class="hljs-string">"<span class="hljs-subst">#{ivar}</span>++"</span>
assigns.push val.compileToFragments o, LEVEL_LIST
<span class="hljs-keyword">continue</span>
<span class="hljs-keyword">else</span>
<span class="hljs-keyword">if</span> obj <span class="hljs-keyword">instanceof</span> Splat <span class="hljs-keyword">or</span> obj <span class="hljs-keyword">instanceof</span> Expansion
obj.error <span class="hljs-string">"multiple splats/expansions are disallowed in an assignment"</span>
defaultValue = <span class="hljs-literal">null</span>
<span class="hljs-keyword">if</span> obj <span class="hljs-keyword">instanceof</span> Assign <span class="hljs-keyword">and</span> obj.context <span class="hljs-keyword">is</span> <span class="hljs-string">'object'</span></pre></div></div>
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<p>A regular object pattern-match.</p>
</div>
<div class="content"><div class='highlight'><pre> {<span class="hljs-attribute">variable</span>: {<span class="hljs-attribute">base</span>: idx}, <span class="hljs-attribute">value</span>: obj} = obj
<span class="hljs-keyword">if</span> obj <span class="hljs-keyword">instanceof</span> Assign
defaultValue = obj.value
obj = obj.variable
<span class="hljs-keyword">else</span>
<span class="hljs-keyword">if</span> obj <span class="hljs-keyword">instanceof</span> Assign
defaultValue = obj.value
obj = obj.variable
idx = <span class="hljs-keyword">if</span> isObject</pre></div></div>
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<p>A shorthand <code>{a, b, @c} = val</code> pattern-match.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-keyword">if</span> obj.<span class="hljs-keyword">this</span> <span class="hljs-keyword">then</span> obj.properties[<span class="hljs-number">0</span>].name <span class="hljs-keyword">else</span> obj
<span class="hljs-keyword">else</span></pre></div></div>
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<p>A regular array pattern-match.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-keyword">new</span> Literal expandedIdx <span class="hljs-keyword">or</span> idx
name = obj.unwrap().value
acc = IDENTIFIER.test idx.unwrap().value
val = <span class="hljs-keyword">new</span> Value <span class="hljs-keyword">new</span> Literal(vvarText), [<span class="hljs-keyword">new</span> (<span class="hljs-keyword">if</span> acc <span class="hljs-keyword">then</span> Access <span class="hljs-keyword">else</span> Index) idx]
val = <span class="hljs-keyword">new</span> Op <span class="hljs-string">'?'</span>, val, defaultValue <span class="hljs-keyword">if</span> defaultValue
<span class="hljs-keyword">if</span> name? <span class="hljs-keyword">and</span> name <span class="hljs-keyword">in</span> RESERVED
obj.error <span class="hljs-string">"assignment to a reserved word: <span class="hljs-subst">#{obj.compile o}</span>"</span>
assigns.push <span class="hljs-keyword">new</span> Assign(obj, val, <span class="hljs-literal">null</span>, <span class="hljs-attribute">param</span>: <span class="hljs-property">@param</span>, <span class="hljs-attribute">subpattern</span>: <span class="hljs-literal">yes</span>).compileToFragments o, LEVEL_LIST
assigns.push vvar <span class="hljs-keyword">unless</span> top <span class="hljs-keyword">or</span> <span class="hljs-property">@subpattern</span>
fragments = <span class="hljs-property">@joinFragmentArrays</span> assigns, <span class="hljs-string">', '</span>
<span class="hljs-keyword">if</span> o.level < LEVEL_LIST <span class="hljs-keyword">then</span> fragments <span class="hljs-keyword">else</span> <span class="hljs-property">@wrapInBraces</span> fragments</pre></div></div>
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<p>When compiling a conditional assignment, take care to ensure that the
operands are only evaluated once, even though we have to reference them
more than once.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">compileConditional</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
[left, right] = <span class="hljs-property">@variable</span>.cacheReference o</pre></div></div>
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<p>Disallow conditional assignment of undefined variables.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-keyword">if</span> <span class="hljs-keyword">not</span> left.properties.length <span class="hljs-keyword">and</span> left.base <span class="hljs-keyword">instanceof</span> Literal <span class="hljs-keyword">and</span>
left.base.value != <span class="hljs-string">"this"</span> <span class="hljs-keyword">and</span> <span class="hljs-keyword">not</span> o.scope.check left.base.value
<span class="hljs-property">@variable</span>.error <span class="hljs-string">"the variable \"<span class="hljs-subst">#{left.base.value}</span>\" can't be assigned with <span class="hljs-subst">#{<span class="hljs-property">@context</span>}</span> because it has not been declared before"</span>
<span class="hljs-keyword">if</span> <span class="hljs-string">"?"</span> <span class="hljs-keyword">in</span> <span class="hljs-property">@context</span>
o.isExistentialEquals = <span class="hljs-literal">true</span>
<span class="hljs-keyword">new</span> If(<span class="hljs-keyword">new</span> Existence(left), right, <span class="hljs-attribute">type</span>: <span class="hljs-string">'if'</span>).addElse(<span class="hljs-keyword">new</span> Assign(right, <span class="hljs-property">@value</span>, <span class="hljs-string">'='</span>)).compileToFragments o
<span class="hljs-keyword">else</span>
fragments = <span class="hljs-keyword">new</span> Op(<span class="hljs-property">@context</span>[...-<span class="hljs-number">1</span>], left, <span class="hljs-keyword">new</span> Assign(right, <span class="hljs-property">@value</span>, <span class="hljs-string">'='</span>)).compileToFragments o
<span class="hljs-keyword">if</span> o.level <= LEVEL_LIST <span class="hljs-keyword">then</span> fragments <span class="hljs-keyword">else</span> <span class="hljs-property">@wrapInBraces</span> fragments</pre></div></div>
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<p>Convert special math assignment operators like <code>a **= b</code> to the equivalent
extended form <code>a = a ** b</code> and then compiles that.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">compileSpecialMath</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
[left, right] = <span class="hljs-property">@variable</span>.cacheReference o
<span class="hljs-keyword">new</span> Assign(left, <span class="hljs-keyword">new</span> Op(<span class="hljs-property">@context</span>[...-<span class="hljs-number">1</span>], right, <span class="hljs-property">@value</span>)).compileToFragments o</pre></div></div>
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<p>Compile the assignment from an array splice literal, using JavaScript’s
<code>Array#splice</code> method.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">compileSplice</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
{<span class="hljs-attribute">range</span>: {from, to, exclusive}} = <span class="hljs-property">@variable</span>.properties.pop()
name = <span class="hljs-property">@variable</span>.compile o
<span class="hljs-keyword">if</span> from
[fromDecl, fromRef] = <span class="hljs-property">@cacheToCodeFragments</span> from.cache o, LEVEL_OP
<span class="hljs-keyword">else</span>
fromDecl = fromRef = <span class="hljs-string">'0'</span>
<span class="hljs-keyword">if</span> to
<span class="hljs-keyword">if</span> from <span class="hljs-keyword">instanceof</span> Value <span class="hljs-keyword">and</span> from.isSimpleNumber() <span class="hljs-keyword">and</span>
to <span class="hljs-keyword">instanceof</span> Value <span class="hljs-keyword">and</span> to.isSimpleNumber()
to = to.compile(o) - fromRef
to += <span class="hljs-number">1</span> <span class="hljs-keyword">unless</span> exclusive
<span class="hljs-keyword">else</span>
to = to.compile(o, LEVEL_ACCESS) + <span class="hljs-string">' - '</span> + fromRef
to += <span class="hljs-string">' + 1'</span> <span class="hljs-keyword">unless</span> exclusive
<span class="hljs-keyword">else</span>
to = <span class="hljs-string">"9e9"</span>
[valDef, valRef] = <span class="hljs-property">@value</span>.cache o, LEVEL_LIST
answer = [].concat <span class="hljs-property">@makeCode</span>(<span class="hljs-string">"[].splice.apply(<span class="hljs-subst">#{name}</span>, [<span class="hljs-subst">#{fromDecl}</span>, <span class="hljs-subst">#{to}</span>].concat("</span>), valDef, <span class="hljs-property">@makeCode</span>(<span class="hljs-string">")), "</span>), valRef
<span class="hljs-keyword">if</span> o.level > LEVEL_TOP <span class="hljs-keyword">then</span> <span class="hljs-property">@wrapInBraces</span> answer <span class="hljs-keyword">else</span> answer</pre></div></div>
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<h3 id="code">Code</h3>
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<p>A function definition. This is the only node that creates a new Scope.
When for the purposes of walking the contents of a function body, the Code
has no <em>children</em> — they’re within the inner scope.</p>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.Code = <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">Code</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">Base</span></span>
<span class="hljs-attribute">constructor</span>: <span class="hljs-function"><span class="hljs-params">(params, body, tag)</span> -></span>
<span class="hljs-property">@params</span> = params <span class="hljs-keyword">or</span> []
<span class="hljs-property">@body</span> = body <span class="hljs-keyword">or</span> <span class="hljs-keyword">new</span> Block
<span class="hljs-property">@bound</span> = tag <span class="hljs-keyword">is</span> <span class="hljs-string">'boundfunc'</span>
<span class="hljs-property">@isGenerator</span> = !!<span class="hljs-property">@body</span>.contains <span class="hljs-function"><span class="hljs-params">(node)</span> -></span>
node <span class="hljs-keyword">instanceof</span> Op <span class="hljs-keyword">and</span> node.operator <span class="hljs-keyword">in</span> [<span class="hljs-string">'yield'</span>, <span class="hljs-string">'yield*'</span>]
<span class="hljs-attribute">children</span>: [<span class="hljs-string">'params'</span>, <span class="hljs-string">'body'</span>]
<span class="hljs-attribute">isStatement</span>:<span class="hljs-function"> -></span> !!<span class="hljs-property">@ctor</span>
<span class="hljs-attribute">jumps</span>: NO
<span class="hljs-attribute">makeScope</span>: <span class="hljs-function"><span class="hljs-params">(parentScope)</span> -></span> <span class="hljs-keyword">new</span> Scope parentScope, <span class="hljs-property">@body</span>, <span class="hljs-keyword">this</span></pre></div></div>
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<p>Compilation creates a new scope unless explicitly asked to share with the
outer scope. Handles splat parameters in the parameter list by peeking at
the JavaScript <code>arguments</code> object. If the function is bound with the <code>=></code>
arrow, generates a wrapper that saves the current value of <code>this</code> through
a closure.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">compileNode</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
<span class="hljs-keyword">if</span> <span class="hljs-property">@bound</span> <span class="hljs-keyword">and</span> o.scope.method?.bound
<span class="hljs-property">@context</span> = o.scope.method.context</pre></div></div>
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<p>Handle bound functions early.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-keyword">if</span> <span class="hljs-property">@bound</span> <span class="hljs-keyword">and</span> <span class="hljs-keyword">not</span> <span class="hljs-property">@context</span>
<span class="hljs-property">@context</span> = <span class="hljs-string">'_this'</span>
wrapper = <span class="hljs-keyword">new</span> Code [<span class="hljs-keyword">new</span> Param <span class="hljs-keyword">new</span> Literal <span class="hljs-property">@context</span>], <span class="hljs-keyword">new</span> Block [<span class="hljs-keyword">this</span>]
boundfunc = <span class="hljs-keyword">new</span> Call(wrapper, [<span class="hljs-keyword">new</span> Literal <span class="hljs-string">'this'</span>])
boundfunc.updateLocationDataIfMissing <span class="hljs-property">@locationData</span>
<span class="hljs-keyword">return</span> boundfunc.compileNode(o)
o.scope = del(o, <span class="hljs-string">'classScope'</span>) <span class="hljs-keyword">or</span> <span class="hljs-property">@makeScope</span> o.scope
o.scope.shared = del(o, <span class="hljs-string">'sharedScope'</span>)
o.indent += TAB
<span class="hljs-keyword">delete</span> o.bare
<span class="hljs-keyword">delete</span> o.isExistentialEquals
params = []
exprs = []
<span class="hljs-keyword">for</span> param <span class="hljs-keyword">in</span> <span class="hljs-property">@params</span> <span class="hljs-keyword">when</span> param <span class="hljs-keyword">not</span> <span class="hljs-keyword">instanceof</span> Expansion
o.scope.parameter param.asReference o
<span class="hljs-keyword">for</span> param <span class="hljs-keyword">in</span> <span class="hljs-property">@params</span> <span class="hljs-keyword">when</span> param.splat <span class="hljs-keyword">or</span> param <span class="hljs-keyword">instanceof</span> Expansion
<span class="hljs-keyword">for</span> p <span class="hljs-keyword">in</span> <span class="hljs-property">@params</span> <span class="hljs-keyword">when</span> p <span class="hljs-keyword">not</span> <span class="hljs-keyword">instanceof</span> Expansion <span class="hljs-keyword">and</span> p.name.value
o.scope.add p.name.value, <span class="hljs-string">'var'</span>, <span class="hljs-literal">yes</span>
splats = <span class="hljs-keyword">new</span> Assign <span class="hljs-keyword">new</span> Value(<span class="hljs-keyword">new</span> Arr(p.asReference o <span class="hljs-keyword">for</span> p <span class="hljs-keyword">in</span> <span class="hljs-property">@params</span>)),
<span class="hljs-keyword">new</span> Value <span class="hljs-keyword">new</span> Literal <span class="hljs-string">'arguments'</span>
<span class="hljs-keyword">break</span>
<span class="hljs-keyword">for</span> param <span class="hljs-keyword">in</span> <span class="hljs-property">@params</span>
<span class="hljs-keyword">if</span> param.isComplex()
val = ref = param.asReference o
val = <span class="hljs-keyword">new</span> Op <span class="hljs-string">'?'</span>, ref, param.value <span class="hljs-keyword">if</span> param.value
exprs.push <span class="hljs-keyword">new</span> Assign <span class="hljs-keyword">new</span> Value(param.name), val, <span class="hljs-string">'='</span>, <span class="hljs-attribute">param</span>: <span class="hljs-literal">yes</span>
<span class="hljs-keyword">else</span>
ref = param
<span class="hljs-keyword">if</span> param.value
lit = <span class="hljs-keyword">new</span> Literal ref.name.value + <span class="hljs-string">' == null'</span>
val = <span class="hljs-keyword">new</span> Assign <span class="hljs-keyword">new</span> Value(param.name), param.value, <span class="hljs-string">'='</span>
exprs.push <span class="hljs-keyword">new</span> If lit, val
params.push ref <span class="hljs-keyword">unless</span> splats
wasEmpty = <span class="hljs-property">@body</span>.isEmpty()
exprs.unshift splats <span class="hljs-keyword">if</span> splats
<span class="hljs-property">@body</span>.expressions.unshift exprs... <span class="hljs-keyword">if</span> exprs.length
<span class="hljs-keyword">for</span> p, i <span class="hljs-keyword">in</span> params
params[i] = p.compileToFragments o
o.scope.parameter fragmentsToText params[i]
uniqs = []
<span class="hljs-property">@eachParamName</span> <span class="hljs-function"><span class="hljs-params">(name, node)</span> -></span>
node.error <span class="hljs-string">"multiple parameters named <span class="hljs-subst">#{name}</span>"</span> <span class="hljs-keyword">if</span> name <span class="hljs-keyword">in</span> uniqs
uniqs.push name
<span class="hljs-property">@body</span>.makeReturn() <span class="hljs-keyword">unless</span> wasEmpty <span class="hljs-keyword">or</span> <span class="hljs-property">@noReturn</span>
code = <span class="hljs-string">'function'</span>
code += <span class="hljs-string">'*'</span> <span class="hljs-keyword">if</span> <span class="hljs-property">@isGenerator</span>
code += <span class="hljs-string">' '</span> + <span class="hljs-property">@name</span> <span class="hljs-keyword">if</span> <span class="hljs-property">@ctor</span>
code += <span class="hljs-string">'('</span>
answer = [<span class="hljs-property">@makeCode</span>(code)]
<span class="hljs-keyword">for</span> p, i <span class="hljs-keyword">in</span> params
<span class="hljs-keyword">if</span> i <span class="hljs-keyword">then</span> answer.push <span class="hljs-property">@makeCode</span> <span class="hljs-string">", "</span>
answer.push p...
answer.push <span class="hljs-property">@makeCode</span> <span class="hljs-string">') {'</span>
answer = answer.concat(<span class="hljs-property">@makeCode</span>(<span class="hljs-string">"\n"</span>), <span class="hljs-property">@body</span>.compileWithDeclarations(o), <span class="hljs-property">@makeCode</span>(<span class="hljs-string">"\n<span class="hljs-subst">#{<span class="hljs-property">@tab</span>}</span>"</span>)) <span class="hljs-keyword">unless</span> <span class="hljs-property">@body</span>.isEmpty()
answer.push <span class="hljs-property">@makeCode</span> <span class="hljs-string">'}'</span>
<span class="hljs-keyword">return</span> [<span class="hljs-property">@makeCode</span>(<span class="hljs-property">@tab</span>), answer...] <span class="hljs-keyword">if</span> <span class="hljs-property">@ctor</span>
<span class="hljs-keyword">if</span> <span class="hljs-property">@front</span> <span class="hljs-keyword">or</span> (o.level >= LEVEL_ACCESS) <span class="hljs-keyword">then</span> <span class="hljs-property">@wrapInBraces</span> answer <span class="hljs-keyword">else</span> answer
<span class="hljs-attribute">eachParamName</span>: <span class="hljs-function"><span class="hljs-params">(iterator)</span> -></span>
param.eachName iterator <span class="hljs-keyword">for</span> param <span class="hljs-keyword">in</span> <span class="hljs-property">@params</span></pre></div></div>
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<p>Short-circuit <code>traverseChildren</code> method to prevent it from crossing scope boundaries
unless <code>crossScope</code> is <code>true</code>.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">traverseChildren</span>: <span class="hljs-function"><span class="hljs-params">(crossScope, func)</span> -></span>
<span class="hljs-keyword">super</span>(crossScope, func) <span class="hljs-keyword">if</span> crossScope</pre></div></div>
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<h3 id="param">Param</h3>
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<p>A parameter in a function definition. Beyond a typical Javascript parameter,
these parameters can also attach themselves to the context of the function,
as well as be a splat, gathering up a group of parameters into an array.</p>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.Param = <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">Param</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">Base</span></span>
<span class="hljs-attribute">constructor</span>: <span class="hljs-function"><span class="hljs-params">(<span class="hljs-property">@name</span>, <span class="hljs-property">@value</span>, <span class="hljs-property">@splat</span>)</span> -></span>
<span class="hljs-keyword">if</span> (name = <span class="hljs-property">@name</span>.unwrapAll().value) <span class="hljs-keyword">in</span> STRICT_PROSCRIBED
<span class="hljs-property">@name</span>.error <span class="hljs-string">"parameter name \"<span class="hljs-subst">#{name}</span>\" is not allowed"</span>
<span class="hljs-keyword">if</span> <span class="hljs-property">@name</span> <span class="hljs-keyword">instanceof</span> Obj <span class="hljs-keyword">and</span> <span class="hljs-property">@name</span>.generated
token = <span class="hljs-property">@name</span>.objects[<span class="hljs-number">0</span>].operatorToken
token.error <span class="hljs-string">"unexpected <span class="hljs-subst">#{token.value}</span>"</span>
<span class="hljs-attribute">children</span>: [<span class="hljs-string">'name'</span>, <span class="hljs-string">'value'</span>]
<span class="hljs-attribute">compileToFragments</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
<span class="hljs-property">@name</span>.compileToFragments o, LEVEL_LIST
<span class="hljs-attribute">asReference</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
<span class="hljs-keyword">return</span> <span class="hljs-property">@reference</span> <span class="hljs-keyword">if</span> <span class="hljs-property">@reference</span>
node = <span class="hljs-property">@name</span>
<span class="hljs-keyword">if</span> node.<span class="hljs-keyword">this</span>
name = node.properties[<span class="hljs-number">0</span>].name.value
name = <span class="hljs-string">"_<span class="hljs-subst">#{name}</span>"</span> <span class="hljs-keyword">if</span> name.reserved
node = <span class="hljs-keyword">new</span> Literal o.scope.freeVariable name
<span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> node.isComplex()
node = <span class="hljs-keyword">new</span> Literal o.scope.freeVariable <span class="hljs-string">'arg'</span>
node = <span class="hljs-keyword">new</span> Value node
node = <span class="hljs-keyword">new</span> Splat node <span class="hljs-keyword">if</span> <span class="hljs-property">@splat</span>
node.updateLocationDataIfMissing <span class="hljs-property">@locationData</span>
<span class="hljs-property">@reference</span> = node
<span class="hljs-attribute">isComplex</span>:<span class="hljs-function"> -></span>
<span class="hljs-property">@name</span>.isComplex()</pre></div></div>
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<p>Iterates the name or names of a <code>Param</code>.
In a sense, a destructured parameter represents multiple JS parameters. This
method allows to iterate them all.
The <code>iterator</code> function will be called as <code>iterator(name, node)</code> where
<code>name</code> is the name of the parameter and <code>node</code> is the AST node corresponding
to that name.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">eachName</span>: <span class="hljs-function"><span class="hljs-params">(iterator, name = <span class="hljs-property">@name</span>)</span>-></span>
<span class="hljs-function"><span class="hljs-title">atParam</span> = <span class="hljs-params">(obj)</span> -></span> iterator <span class="hljs-string">"@<span class="hljs-subst">#{obj.properties[<span class="hljs-number">0</span>].name.value}</span>"</span>, obj</pre></div></div>
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<ul>
<li>simple literals <code>foo</code></li>
</ul>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-keyword">return</span> iterator name.value, name <span class="hljs-keyword">if</span> name <span class="hljs-keyword">instanceof</span> Literal</pre></div></div>
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<ul>
<li>at-params <code>@foo</code></li>
</ul>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-keyword">return</span> atParam name <span class="hljs-keyword">if</span> name <span class="hljs-keyword">instanceof</span> Value
<span class="hljs-keyword">for</span> obj <span class="hljs-keyword">in</span> name.objects</pre></div></div>
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<ul>
<li>destructured parameter with default value</li>
</ul>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-keyword">if</span> obj <span class="hljs-keyword">instanceof</span> Assign <span class="hljs-keyword">and</span> <span class="hljs-keyword">not</span> obj.context?
obj = obj.variable</pre></div></div>
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<ul>
<li>assignments within destructured parameters <code>{foo:bar}</code></li>
</ul>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-keyword">if</span> obj <span class="hljs-keyword">instanceof</span> Assign
<span class="hljs-property">@eachName</span> iterator, obj.value.unwrap()</pre></div></div>
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<ul>
<li>splats within destructured parameters <code>[xs...]</code></li>
</ul>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> obj <span class="hljs-keyword">instanceof</span> Splat
node = obj.name.unwrap()
iterator node.value, node
<span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> obj <span class="hljs-keyword">instanceof</span> Value</pre></div></div>
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<ul>
<li>destructured parameters within destructured parameters <code>[{a}]</code></li>
</ul>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-keyword">if</span> obj.isArray() <span class="hljs-keyword">or</span> obj.isObject()
<span class="hljs-property">@eachName</span> iterator, obj.base</pre></div></div>
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<ul>
<li>at-params within destructured parameters <code>{@foo}</code></li>
</ul>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> obj.<span class="hljs-keyword">this</span>
atParam obj</pre></div></div>
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<ul>
<li>simple destructured parameters {foo}</li>
</ul>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-keyword">else</span> iterator obj.base.value, obj.base
<span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> obj <span class="hljs-keyword">not</span> <span class="hljs-keyword">instanceof</span> Expansion
obj.error <span class="hljs-string">"illegal parameter <span class="hljs-subst">#{obj.compile()}</span>"</span>
<span class="hljs-keyword">return</span></pre></div></div>
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<h3 id="splat">Splat</h3>
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<p>A splat, either as a parameter to a function, an argument to a call,
or as part of a destructuring assignment.</p>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.Splat = <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">Splat</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">Base</span></span>
<span class="hljs-attribute">children</span>: [<span class="hljs-string">'name'</span>]
<span class="hljs-attribute">isAssignable</span>: YES
<span class="hljs-attribute">constructor</span>: <span class="hljs-function"><span class="hljs-params">(name)</span> -></span>
<span class="hljs-property">@name</span> = <span class="hljs-keyword">if</span> name.compile <span class="hljs-keyword">then</span> name <span class="hljs-keyword">else</span> <span class="hljs-keyword">new</span> Literal name
<span class="hljs-attribute">assigns</span>: <span class="hljs-function"><span class="hljs-params">(name)</span> -></span>
<span class="hljs-property">@name</span>.assigns name
<span class="hljs-attribute">compileToFragments</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
<span class="hljs-property">@name</span>.compileToFragments o
<span class="hljs-attribute">unwrap</span>:<span class="hljs-function"> -></span> <span class="hljs-property">@name</span></pre></div></div>
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<p>Utility function that converts an arbitrary number of elements, mixed with
splats, to a proper array.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-property">@compileSplattedArray</span>: <span class="hljs-function"><span class="hljs-params">(o, list, apply)</span> -></span>
index = -<span class="hljs-number">1</span>
<span class="hljs-keyword">continue</span> <span class="hljs-keyword">while</span> (node = list[++index]) <span class="hljs-keyword">and</span> node <span class="hljs-keyword">not</span> <span class="hljs-keyword">instanceof</span> Splat
<span class="hljs-keyword">return</span> [] <span class="hljs-keyword">if</span> index >= list.length
<span class="hljs-keyword">if</span> list.length <span class="hljs-keyword">is</span> <span class="hljs-number">1</span>
node = list[<span class="hljs-number">0</span>]
fragments = node.compileToFragments o, LEVEL_LIST
<span class="hljs-keyword">return</span> fragments <span class="hljs-keyword">if</span> apply
<span class="hljs-keyword">return</span> [].concat node.makeCode(<span class="hljs-string">"<span class="hljs-subst">#{ utility <span class="hljs-string">'slice'</span>, o }</span>.call("</span>), fragments, node.makeCode(<span class="hljs-string">")"</span>)
args = list[index..]
<span class="hljs-keyword">for</span> node, i <span class="hljs-keyword">in</span> args
compiledNode = node.compileToFragments o, LEVEL_LIST
args[i] = <span class="hljs-keyword">if</span> node <span class="hljs-keyword">instanceof</span> Splat
<span class="hljs-keyword">then</span> [].concat node.makeCode(<span class="hljs-string">"<span class="hljs-subst">#{ utility <span class="hljs-string">'slice'</span>, o }</span>.call("</span>), compiledNode, node.makeCode(<span class="hljs-string">")"</span>)
<span class="hljs-keyword">else</span> [].concat node.makeCode(<span class="hljs-string">"["</span>), compiledNode, node.makeCode(<span class="hljs-string">"]"</span>)
<span class="hljs-keyword">if</span> index <span class="hljs-keyword">is</span> <span class="hljs-number">0</span>
node = list[<span class="hljs-number">0</span>]
concatPart = (node.joinFragmentArrays args[<span class="hljs-number">1.</span>.], <span class="hljs-string">', '</span>)
<span class="hljs-keyword">return</span> args[<span class="hljs-number">0</span>].concat node.makeCode(<span class="hljs-string">".concat("</span>), concatPart, node.makeCode(<span class="hljs-string">")"</span>)
base = (node.compileToFragments o, LEVEL_LIST <span class="hljs-keyword">for</span> node <span class="hljs-keyword">in</span> list[...index])
base = list[<span class="hljs-number">0</span>].joinFragmentArrays base, <span class="hljs-string">', '</span>
concatPart = list[index].joinFragmentArrays args, <span class="hljs-string">', '</span>
[..., last] = list
[].concat list[<span class="hljs-number">0</span>].makeCode(<span class="hljs-string">"["</span>), base, list[index].makeCode(<span class="hljs-string">"].concat("</span>), concatPart, last.makeCode(<span class="hljs-string">")"</span>)</pre></div></div>
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<h3 id="expansion">Expansion</h3>
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<p>Used to skip values inside an array destructuring (pattern matching) or
parameter list.</p>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.Expansion = <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">Expansion</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">Base</span></span>
<span class="hljs-attribute">isComplex</span>: NO
<span class="hljs-attribute">compileNode</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
<span class="hljs-property">@error</span> <span class="hljs-string">'Expansion must be used inside a destructuring assignment or parameter list'</span>
<span class="hljs-attribute">asReference</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
<span class="hljs-keyword">this</span>
<span class="hljs-attribute">eachName</span>: <span class="hljs-function"><span class="hljs-params">(iterator)</span> -></span></pre></div></div>
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<h3 id="while">While</h3>
</div>
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<p>A while loop, the only sort of low-level loop exposed by CoffeeScript. From
it, all other loops can be manufactured. Useful in cases where you need more
flexibility or more speed than a comprehension can provide.</p>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.While = <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">While</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">Base</span></span>
<span class="hljs-attribute">constructor</span>: <span class="hljs-function"><span class="hljs-params">(condition, options)</span> -></span>
<span class="hljs-property">@condition</span> = <span class="hljs-keyword">if</span> options?.invert <span class="hljs-keyword">then</span> condition.invert() <span class="hljs-keyword">else</span> condition
<span class="hljs-property">@guard</span> = options?.guard
<span class="hljs-attribute">children</span>: [<span class="hljs-string">'condition'</span>, <span class="hljs-string">'guard'</span>, <span class="hljs-string">'body'</span>]
<span class="hljs-attribute">isStatement</span>: YES
<span class="hljs-attribute">makeReturn</span>: <span class="hljs-function"><span class="hljs-params">(res)</span> -></span>
<span class="hljs-keyword">if</span> res
<span class="hljs-keyword">super</span>
<span class="hljs-keyword">else</span>
<span class="hljs-property">@returns</span> = <span class="hljs-keyword">not</span> <span class="hljs-property">@jumps</span> <span class="hljs-attribute">loop</span>: <span class="hljs-literal">yes</span>
<span class="hljs-keyword">this</span>
<span class="hljs-attribute">addBody</span>: <span class="hljs-function"><span class="hljs-params">(<span class="hljs-property">@body</span>)</span> -></span>
<span class="hljs-keyword">this</span>
<span class="hljs-attribute">jumps</span>:<span class="hljs-function"> -></span>
{expressions} = <span class="hljs-property">@body</span>
<span class="hljs-keyword">return</span> <span class="hljs-literal">no</span> <span class="hljs-keyword">unless</span> expressions.length
<span class="hljs-keyword">for</span> node <span class="hljs-keyword">in</span> expressions
<span class="hljs-keyword">return</span> jumpNode <span class="hljs-keyword">if</span> jumpNode = node.jumps <span class="hljs-attribute">loop</span>: <span class="hljs-literal">yes</span>
<span class="hljs-literal">no</span></pre></div></div>
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<p>The main difference from a JavaScript <em>while</em> is that the CoffeeScript
<em>while</em> can be used as a part of a larger expression — while loops may
return an array containing the computed result of each iteration.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">compileNode</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
o.indent += TAB
set = <span class="hljs-string">''</span>
{body} = <span class="hljs-keyword">this</span>
<span class="hljs-keyword">if</span> body.isEmpty()
body = <span class="hljs-property">@makeCode</span> <span class="hljs-string">''</span>
<span class="hljs-keyword">else</span>
<span class="hljs-keyword">if</span> <span class="hljs-property">@returns</span>
body.makeReturn rvar = o.scope.freeVariable <span class="hljs-string">'results'</span>
set = <span class="hljs-string">"<span class="hljs-subst">#{<span class="hljs-property">@tab</span>}</span><span class="hljs-subst">#{rvar}</span> = [];\n"</span>
<span class="hljs-keyword">if</span> <span class="hljs-property">@guard</span>
<span class="hljs-keyword">if</span> body.expressions.length > <span class="hljs-number">1</span>
body.expressions.unshift <span class="hljs-keyword">new</span> If (<span class="hljs-keyword">new</span> Parens <span class="hljs-property">@guard</span>).invert(), <span class="hljs-keyword">new</span> Literal <span class="hljs-string">"continue"</span>
<span class="hljs-keyword">else</span>
body = Block.wrap [<span class="hljs-keyword">new</span> If <span class="hljs-property">@guard</span>, body] <span class="hljs-keyword">if</span> <span class="hljs-property">@guard</span>
body = [].concat <span class="hljs-property">@makeCode</span>(<span class="hljs-string">"\n"</span>), (body.compileToFragments o, LEVEL_TOP), <span class="hljs-property">@makeCode</span>(<span class="hljs-string">"\n<span class="hljs-subst">#{<span class="hljs-property">@tab</span>}</span>"</span>)
answer = [].concat <span class="hljs-property">@makeCode</span>(set + <span class="hljs-property">@tab</span> + <span class="hljs-string">"while ("</span>), <span class="hljs-property">@condition</span>.compileToFragments(o, LEVEL_PAREN),
<span class="hljs-property">@makeCode</span>(<span class="hljs-string">") {"</span>), body, <span class="hljs-property">@makeCode</span>(<span class="hljs-string">"}"</span>)
<span class="hljs-keyword">if</span> <span class="hljs-property">@returns</span>
answer.push <span class="hljs-property">@makeCode</span> <span class="hljs-string">"\n<span class="hljs-subst">#{<span class="hljs-property">@tab</span>}</span>return <span class="hljs-subst">#{rvar}</span>;"</span>
answer</pre></div></div>
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<h3 id="op">Op</h3>
</div>
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<p>Simple Arithmetic and logical operations. Performs some conversion from
CoffeeScript operations into their JavaScript equivalents.</p>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.Op = <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">Op</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">Base</span></span>
<span class="hljs-attribute">constructor</span>: <span class="hljs-function"><span class="hljs-params">(op, first, second, flip )</span> -></span>
<span class="hljs-keyword">return</span> <span class="hljs-keyword">new</span> In first, second <span class="hljs-keyword">if</span> op <span class="hljs-keyword">is</span> <span class="hljs-string">'in'</span>
<span class="hljs-keyword">if</span> op <span class="hljs-keyword">is</span> <span class="hljs-string">'do'</span>
<span class="hljs-keyword">return</span> <span class="hljs-property">@generateDo</span> first
<span class="hljs-keyword">if</span> op <span class="hljs-keyword">is</span> <span class="hljs-string">'new'</span>
<span class="hljs-keyword">return</span> first.newInstance() <span class="hljs-keyword">if</span> first <span class="hljs-keyword">instanceof</span> Call <span class="hljs-keyword">and</span> <span class="hljs-keyword">not</span> first.<span class="hljs-keyword">do</span> <span class="hljs-keyword">and</span> <span class="hljs-keyword">not</span> first.isNew
first = <span class="hljs-keyword">new</span> Parens first <span class="hljs-keyword">if</span> first <span class="hljs-keyword">instanceof</span> Code <span class="hljs-keyword">and</span> first.bound <span class="hljs-keyword">or</span> first.<span class="hljs-keyword">do</span>
<span class="hljs-property">@operator</span> = CONVERSIONS[op] <span class="hljs-keyword">or</span> op
<span class="hljs-property">@first</span> = first
<span class="hljs-property">@second</span> = second
<span class="hljs-property">@flip</span> = !!flip
<span class="hljs-keyword">return</span> <span class="hljs-keyword">this</span></pre></div></div>
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<p>The map of conversions from CoffeeScript to JavaScript symbols.</p>
</div>
<div class="content"><div class='highlight'><pre> CONVERSIONS =
<span class="hljs-string">'=='</span>: <span class="hljs-string">'==='</span>
<span class="hljs-string">'!='</span>: <span class="hljs-string">'!=='</span>
<span class="hljs-string">'of'</span>: <span class="hljs-string">'in'</span>
<span class="hljs-string">'yieldfrom'</span>: <span class="hljs-string">'yield*'</span></pre></div></div>
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<p>The map of invertible operators.</p>
</div>
<div class="content"><div class='highlight'><pre> INVERSIONS =
<span class="hljs-string">'!=='</span>: <span class="hljs-string">'==='</span>
<span class="hljs-string">'==='</span>: <span class="hljs-string">'!=='</span>
<span class="hljs-attribute">children</span>: [<span class="hljs-string">'first'</span>, <span class="hljs-string">'second'</span>]
<span class="hljs-attribute">isSimpleNumber</span>: NO
<span class="hljs-attribute">isYield</span>:<span class="hljs-function"> -></span>
<span class="hljs-property">@operator</span> <span class="hljs-keyword">in</span> [<span class="hljs-string">'yield'</span>, <span class="hljs-string">'yield*'</span>]
<span class="hljs-attribute">isYieldReturn</span>:<span class="hljs-function"> -></span>
<span class="hljs-property">@isYield</span>() <span class="hljs-keyword">and</span> <span class="hljs-property">@first</span> <span class="hljs-keyword">instanceof</span> Return
<span class="hljs-attribute">isUnary</span>:<span class="hljs-function"> -></span>
<span class="hljs-keyword">not</span> <span class="hljs-property">@second</span>
<span class="hljs-attribute">isComplex</span>:<span class="hljs-function"> -></span>
<span class="hljs-keyword">not</span> (<span class="hljs-property">@isUnary</span>() <span class="hljs-keyword">and</span> <span class="hljs-property">@operator</span> <span class="hljs-keyword">in</span> [<span class="hljs-string">'+'</span>, <span class="hljs-string">'-'</span>] <span class="hljs-keyword">and</span>
<span class="hljs-property">@first</span> <span class="hljs-keyword">instanceof</span> Value <span class="hljs-keyword">and</span> <span class="hljs-property">@first</span>.isSimpleNumber())</pre></div></div>
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<p>Am I capable of
<a href="http://docs.python.org/reference/expressions.html#notin">Python-style comparison chaining</a>?</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">isChainable</span>:<span class="hljs-function"> -></span>
<span class="hljs-property">@operator</span> <span class="hljs-keyword">in</span> [<span class="hljs-string">'<'</span>, <span class="hljs-string">'>'</span>, <span class="hljs-string">'>='</span>, <span class="hljs-string">'<='</span>, <span class="hljs-string">'==='</span>, <span class="hljs-string">'!=='</span>]
<span class="hljs-attribute">invert</span>:<span class="hljs-function"> -></span>
<span class="hljs-keyword">if</span> <span class="hljs-property">@isChainable</span>() <span class="hljs-keyword">and</span> <span class="hljs-property">@first</span>.isChainable()
allInvertable = <span class="hljs-literal">yes</span>
curr = <span class="hljs-keyword">this</span>
<span class="hljs-keyword">while</span> curr <span class="hljs-keyword">and</span> curr.operator
allInvertable <span class="hljs-keyword">and</span>= (curr.operator <span class="hljs-keyword">of</span> INVERSIONS)
curr = curr.first
<span class="hljs-keyword">return</span> <span class="hljs-keyword">new</span> Parens(<span class="hljs-keyword">this</span>).invert() <span class="hljs-keyword">unless</span> allInvertable
curr = <span class="hljs-keyword">this</span>
<span class="hljs-keyword">while</span> curr <span class="hljs-keyword">and</span> curr.operator
curr.invert = !curr.invert
curr.operator = INVERSIONS[curr.operator]
curr = curr.first
<span class="hljs-keyword">this</span>
<span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> op = INVERSIONS[<span class="hljs-property">@operator</span>]
<span class="hljs-property">@operator</span> = op
<span class="hljs-keyword">if</span> <span class="hljs-property">@first</span>.unwrap() <span class="hljs-keyword">instanceof</span> Op
<span class="hljs-property">@first</span>.invert()
<span class="hljs-keyword">this</span>
<span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> <span class="hljs-property">@second</span>
<span class="hljs-keyword">new</span> Parens(<span class="hljs-keyword">this</span>).invert()
<span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> <span class="hljs-property">@operator</span> <span class="hljs-keyword">is</span> <span class="hljs-string">'!'</span> <span class="hljs-keyword">and</span> (fst = <span class="hljs-property">@first</span>.unwrap()) <span class="hljs-keyword">instanceof</span> Op <span class="hljs-keyword">and</span>
fst.operator <span class="hljs-keyword">in</span> [<span class="hljs-string">'!'</span>, <span class="hljs-string">'in'</span>, <span class="hljs-string">'instanceof'</span>]
fst
<span class="hljs-keyword">else</span>
<span class="hljs-keyword">new</span> Op <span class="hljs-string">'!'</span>, <span class="hljs-keyword">this</span>
<span class="hljs-attribute">unfoldSoak</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
<span class="hljs-property">@operator</span> <span class="hljs-keyword">in</span> [<span class="hljs-string">'++'</span>, <span class="hljs-string">'--'</span>, <span class="hljs-string">'delete'</span>] <span class="hljs-keyword">and</span> unfoldSoak o, <span class="hljs-keyword">this</span>, <span class="hljs-string">'first'</span>
<span class="hljs-attribute">generateDo</span>: <span class="hljs-function"><span class="hljs-params">(exp)</span> -></span>
passedParams = []
func = <span class="hljs-keyword">if</span> exp <span class="hljs-keyword">instanceof</span> Assign <span class="hljs-keyword">and</span> (ref = exp.value.unwrap()) <span class="hljs-keyword">instanceof</span> Code
ref
<span class="hljs-keyword">else</span>
exp
<span class="hljs-keyword">for</span> param <span class="hljs-keyword">in</span> func.params <span class="hljs-keyword">or</span> []
<span class="hljs-keyword">if</span> param.value
passedParams.push param.value
<span class="hljs-keyword">delete</span> param.value
<span class="hljs-keyword">else</span>
passedParams.push param
call = <span class="hljs-keyword">new</span> Call exp, passedParams
call.<span class="hljs-keyword">do</span> = <span class="hljs-literal">yes</span>
call
<span class="hljs-attribute">compileNode</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
isChain = <span class="hljs-property">@isChainable</span>() <span class="hljs-keyword">and</span> <span class="hljs-property">@first</span>.isChainable()</pre></div></div>
</li>
<li id="section-140">
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<p>In chains, there’s no need to wrap bare obj literals in parens,
as the chained expression is wrapped.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-property">@first</span>.front = <span class="hljs-property">@front</span> <span class="hljs-keyword">unless</span> isChain
<span class="hljs-keyword">if</span> <span class="hljs-property">@operator</span> <span class="hljs-keyword">is</span> <span class="hljs-string">'delete'</span> <span class="hljs-keyword">and</span> o.scope.check(<span class="hljs-property">@first</span>.unwrapAll().value)
<span class="hljs-property">@error</span> <span class="hljs-string">'delete operand may not be argument or var'</span>
<span class="hljs-keyword">if</span> <span class="hljs-property">@operator</span> <span class="hljs-keyword">in</span> [<span class="hljs-string">'--'</span>, <span class="hljs-string">'++'</span>] <span class="hljs-keyword">and</span> <span class="hljs-property">@first</span>.unwrapAll().value <span class="hljs-keyword">in</span> STRICT_PROSCRIBED
<span class="hljs-property">@error</span> <span class="hljs-string">"cannot increment/decrement \"<span class="hljs-subst">#{<span class="hljs-property">@first</span>.unwrapAll().value}</span>\""</span>
<span class="hljs-keyword">return</span> <span class="hljs-property">@compileYield</span> o <span class="hljs-keyword">if</span> <span class="hljs-property">@isYield</span>()
<span class="hljs-keyword">return</span> <span class="hljs-property">@compileUnary</span> o <span class="hljs-keyword">if</span> <span class="hljs-property">@isUnary</span>()
<span class="hljs-keyword">return</span> <span class="hljs-property">@compileChain</span> o <span class="hljs-keyword">if</span> isChain
<span class="hljs-keyword">switch</span> <span class="hljs-property">@operator</span>
<span class="hljs-keyword">when</span> <span class="hljs-string">'?'</span> <span class="hljs-keyword">then</span> <span class="hljs-property">@compileExistence</span> o
<span class="hljs-keyword">when</span> <span class="hljs-string">'**'</span> <span class="hljs-keyword">then</span> <span class="hljs-property">@compilePower</span> o
<span class="hljs-keyword">when</span> <span class="hljs-string">'//'</span> <span class="hljs-keyword">then</span> <span class="hljs-property">@compileFloorDivision</span> o
<span class="hljs-keyword">when</span> <span class="hljs-string">'%%'</span> <span class="hljs-keyword">then</span> <span class="hljs-property">@compileModulo</span> o
<span class="hljs-keyword">else</span>
lhs = <span class="hljs-property">@first</span>.compileToFragments o, LEVEL_OP
rhs = <span class="hljs-property">@second</span>.compileToFragments o, LEVEL_OP
answer = [].concat lhs, <span class="hljs-property">@makeCode</span>(<span class="hljs-string">" <span class="hljs-subst">#{<span class="hljs-property">@operator</span>}</span> "</span>), rhs
<span class="hljs-keyword">if</span> o.level <= LEVEL_OP <span class="hljs-keyword">then</span> answer <span class="hljs-keyword">else</span> <span class="hljs-property">@wrapInBraces</span> answer</pre></div></div>
</li>
<li id="section-141">
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<p>Mimic Python’s chained comparisons when multiple comparison operators are
used sequentially. For example:</p>
<pre><code>bin/coffee -e <span class="hljs-string">'console.log 50 < 65 > 10'</span>
<span class="hljs-literal">true</span>
</code></pre>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">compileChain</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
[<span class="hljs-property">@first</span>.second, shared] = <span class="hljs-property">@first</span>.second.cache o
fst = <span class="hljs-property">@first</span>.compileToFragments o, LEVEL_OP
fragments = fst.concat <span class="hljs-property">@makeCode</span>(<span class="hljs-string">" <span class="hljs-subst">#{<span class="hljs-keyword">if</span> <span class="hljs-property">@invert</span> <span class="hljs-keyword">then</span> <span class="hljs-string">'&&'</span> <span class="hljs-keyword">else</span> <span class="hljs-string">'||'</span>}</span> "</span>),
(shared.compileToFragments o), <span class="hljs-property">@makeCode</span>(<span class="hljs-string">" <span class="hljs-subst">#{<span class="hljs-property">@operator</span>}</span> "</span>), (<span class="hljs-property">@second</span>.compileToFragments o, LEVEL_OP)
<span class="hljs-property">@wrapInBraces</span> fragments</pre></div></div>
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<p>Keep reference to the left expression, unless this an existential assignment</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">compileExistence</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
<span class="hljs-keyword">if</span> <span class="hljs-property">@first</span>.isComplex()
ref = <span class="hljs-keyword">new</span> Literal o.scope.freeVariable <span class="hljs-string">'ref'</span>
fst = <span class="hljs-keyword">new</span> Parens <span class="hljs-keyword">new</span> Assign ref, <span class="hljs-property">@first</span>
<span class="hljs-keyword">else</span>
fst = <span class="hljs-property">@first</span>
ref = fst
<span class="hljs-keyword">new</span> If(<span class="hljs-keyword">new</span> Existence(fst), ref, <span class="hljs-attribute">type</span>: <span class="hljs-string">'if'</span>).addElse(<span class="hljs-property">@second</span>).compileToFragments o</pre></div></div>
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<p>Compile a unary <strong>Op</strong>.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">compileUnary</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
parts = []
op = <span class="hljs-property">@operator</span>
parts.push [<span class="hljs-property">@makeCode</span> op]
<span class="hljs-keyword">if</span> op <span class="hljs-keyword">is</span> <span class="hljs-string">'!'</span> <span class="hljs-keyword">and</span> <span class="hljs-property">@first</span> <span class="hljs-keyword">instanceof</span> Existence
<span class="hljs-property">@first</span>.negated = <span class="hljs-keyword">not</span> <span class="hljs-property">@first</span>.negated
<span class="hljs-keyword">return</span> <span class="hljs-property">@first</span>.compileToFragments o
<span class="hljs-keyword">if</span> o.level >= LEVEL_ACCESS
<span class="hljs-keyword">return</span> (<span class="hljs-keyword">new</span> Parens <span class="hljs-keyword">this</span>).compileToFragments o
plusMinus = op <span class="hljs-keyword">in</span> [<span class="hljs-string">'+'</span>, <span class="hljs-string">'-'</span>]
parts.push [<span class="hljs-property">@makeCode</span>(<span class="hljs-string">' '</span>)] <span class="hljs-keyword">if</span> op <span class="hljs-keyword">in</span> [<span class="hljs-string">'new'</span>, <span class="hljs-string">'typeof'</span>, <span class="hljs-string">'delete'</span>] <span class="hljs-keyword">or</span>
plusMinus <span class="hljs-keyword">and</span> <span class="hljs-property">@first</span> <span class="hljs-keyword">instanceof</span> Op <span class="hljs-keyword">and</span> <span class="hljs-property">@first</span>.operator <span class="hljs-keyword">is</span> op
<span class="hljs-keyword">if</span> (plusMinus <span class="hljs-keyword">and</span> <span class="hljs-property">@first</span> <span class="hljs-keyword">instanceof</span> Op) <span class="hljs-keyword">or</span> (op <span class="hljs-keyword">is</span> <span class="hljs-string">'new'</span> <span class="hljs-keyword">and</span> <span class="hljs-property">@first</span>.isStatement o)
<span class="hljs-property">@first</span> = <span class="hljs-keyword">new</span> Parens <span class="hljs-property">@first</span>
parts.push <span class="hljs-property">@first</span>.compileToFragments o, LEVEL_OP
parts.reverse() <span class="hljs-keyword">if</span> <span class="hljs-property">@flip</span>
<span class="hljs-property">@joinFragmentArrays</span> parts, <span class="hljs-string">''</span>
<span class="hljs-attribute">compileYield</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
parts = []
op = <span class="hljs-property">@operator</span>
<span class="hljs-keyword">if</span> <span class="hljs-keyword">not</span> o.scope.parent?
<span class="hljs-property">@error</span> <span class="hljs-string">'yield statements must occur within a function generator.'</span>
<span class="hljs-keyword">if</span> <span class="hljs-string">'expression'</span> <span class="hljs-keyword">in</span> Object.keys(<span class="hljs-property">@first</span>) <span class="hljs-keyword">and</span> <span class="hljs-keyword">not</span> (<span class="hljs-property">@first</span> <span class="hljs-keyword">instanceof</span> Throw)
<span class="hljs-keyword">if</span> <span class="hljs-property">@isYieldReturn</span>()
parts.push <span class="hljs-property">@first</span>.compileToFragments o, LEVEL_TOP
<span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> <span class="hljs-property">@first</span>.expression?
parts.push <span class="hljs-property">@first</span>.expression.compileToFragments o, LEVEL_OP
<span class="hljs-keyword">else</span>
parts.push [<span class="hljs-property">@makeCode</span> <span class="hljs-string">"(<span class="hljs-subst">#{op}</span> "</span>]
parts.push <span class="hljs-property">@first</span>.compileToFragments o, LEVEL_OP
parts.push [<span class="hljs-property">@makeCode</span> <span class="hljs-string">")"</span>]
<span class="hljs-property">@joinFragmentArrays</span> parts, <span class="hljs-string">''</span>
<span class="hljs-attribute">compilePower</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span></pre></div></div>
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<p>Make a Math.pow call</p>
</div>
<div class="content"><div class='highlight'><pre> pow = <span class="hljs-keyword">new</span> Value <span class="hljs-keyword">new</span> Literal(<span class="hljs-string">'Math'</span>), [<span class="hljs-keyword">new</span> Access <span class="hljs-keyword">new</span> Literal <span class="hljs-string">'pow'</span>]
<span class="hljs-keyword">new</span> Call(pow, [<span class="hljs-property">@first</span>, <span class="hljs-property">@second</span>]).compileToFragments o
<span class="hljs-attribute">compileFloorDivision</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
floor = <span class="hljs-keyword">new</span> Value <span class="hljs-keyword">new</span> Literal(<span class="hljs-string">'Math'</span>), [<span class="hljs-keyword">new</span> Access <span class="hljs-keyword">new</span> Literal <span class="hljs-string">'floor'</span>]
div = <span class="hljs-keyword">new</span> Op <span class="hljs-string">'/'</span>, <span class="hljs-property">@first</span>, <span class="hljs-property">@second</span>
<span class="hljs-keyword">new</span> Call(floor, [div]).compileToFragments o
<span class="hljs-attribute">compileModulo</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
mod = <span class="hljs-keyword">new</span> Value <span class="hljs-keyword">new</span> Literal utility <span class="hljs-string">'modulo'</span>, o
<span class="hljs-keyword">new</span> Call(mod, [<span class="hljs-property">@first</span>, <span class="hljs-property">@second</span>]).compileToFragments o
<span class="hljs-attribute">toString</span>: <span class="hljs-function"><span class="hljs-params">(idt)</span> -></span>
<span class="hljs-keyword">super</span> idt, <span class="hljs-property">@constructor</span>.name + <span class="hljs-string">' '</span> + <span class="hljs-property">@operator</span></pre></div></div>
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<h3 id="in">In</h3>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.In = <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">In</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">Base</span></span>
<span class="hljs-attribute">constructor</span>: <span class="hljs-function"><span class="hljs-params">(<span class="hljs-property">@object</span>, <span class="hljs-property">@array</span>)</span> -></span>
<span class="hljs-attribute">children</span>: [<span class="hljs-string">'object'</span>, <span class="hljs-string">'array'</span>]
<span class="hljs-attribute">invert</span>: NEGATE
<span class="hljs-attribute">compileNode</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
<span class="hljs-keyword">if</span> <span class="hljs-property">@array</span> <span class="hljs-keyword">instanceof</span> Value <span class="hljs-keyword">and</span> <span class="hljs-property">@array</span>.isArray() <span class="hljs-keyword">and</span> <span class="hljs-property">@array</span>.base.objects.length
<span class="hljs-keyword">for</span> obj <span class="hljs-keyword">in</span> <span class="hljs-property">@array</span>.base.objects <span class="hljs-keyword">when</span> obj <span class="hljs-keyword">instanceof</span> Splat
hasSplat = <span class="hljs-literal">yes</span>
<span class="hljs-keyword">break</span></pre></div></div>
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<p><code>compileOrTest</code> only if we have an array literal with no splats</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-keyword">return</span> <span class="hljs-property">@compileOrTest</span> o <span class="hljs-keyword">unless</span> hasSplat
<span class="hljs-property">@compileLoopTest</span> o
<span class="hljs-attribute">compileOrTest</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
[sub, ref] = <span class="hljs-property">@object</span>.cache o, LEVEL_OP
[cmp, cnj] = <span class="hljs-keyword">if</span> <span class="hljs-property">@negated</span> <span class="hljs-keyword">then</span> [<span class="hljs-string">' !== '</span>, <span class="hljs-string">' && '</span>] <span class="hljs-keyword">else</span> [<span class="hljs-string">' === '</span>, <span class="hljs-string">' || '</span>]
tests = []
<span class="hljs-keyword">for</span> item, i <span class="hljs-keyword">in</span> <span class="hljs-property">@array</span>.base.objects
<span class="hljs-keyword">if</span> i <span class="hljs-keyword">then</span> tests.push <span class="hljs-property">@makeCode</span> cnj
tests = tests.concat (<span class="hljs-keyword">if</span> i <span class="hljs-keyword">then</span> ref <span class="hljs-keyword">else</span> sub), <span class="hljs-property">@makeCode</span>(cmp), item.compileToFragments(o, LEVEL_ACCESS)
<span class="hljs-keyword">if</span> o.level < LEVEL_OP <span class="hljs-keyword">then</span> tests <span class="hljs-keyword">else</span> <span class="hljs-property">@wrapInBraces</span> tests
<span class="hljs-attribute">compileLoopTest</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
[sub, ref] = <span class="hljs-property">@object</span>.cache o, LEVEL_LIST
fragments = [].concat <span class="hljs-property">@makeCode</span>(utility(<span class="hljs-string">'indexOf'</span>, o) + <span class="hljs-string">".call("</span>), <span class="hljs-property">@array</span>.compileToFragments(o, LEVEL_LIST),
<span class="hljs-property">@makeCode</span>(<span class="hljs-string">", "</span>), ref, <span class="hljs-property">@makeCode</span>(<span class="hljs-string">") "</span> + <span class="hljs-keyword">if</span> <span class="hljs-property">@negated</span> <span class="hljs-keyword">then</span> <span class="hljs-string">'< 0'</span> <span class="hljs-keyword">else</span> <span class="hljs-string">'>= 0'</span>)
<span class="hljs-keyword">return</span> fragments <span class="hljs-keyword">if</span> fragmentsToText(sub) <span class="hljs-keyword">is</span> fragmentsToText(ref)
fragments = sub.concat <span class="hljs-property">@makeCode</span>(<span class="hljs-string">', '</span>), fragments
<span class="hljs-keyword">if</span> o.level < LEVEL_LIST <span class="hljs-keyword">then</span> fragments <span class="hljs-keyword">else</span> <span class="hljs-property">@wrapInBraces</span> fragments
<span class="hljs-attribute">toString</span>: <span class="hljs-function"><span class="hljs-params">(idt)</span> -></span>
<span class="hljs-keyword">super</span> idt, <span class="hljs-property">@constructor</span>.name + <span class="hljs-keyword">if</span> <span class="hljs-property">@negated</span> <span class="hljs-keyword">then</span> <span class="hljs-string">'!'</span> <span class="hljs-keyword">else</span> <span class="hljs-string">''</span></pre></div></div>
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<h3 id="try">Try</h3>
</div>
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<p>A classic <em>try/catch/finally</em> block.</p>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.Try = <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">Try</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">Base</span></span>
<span class="hljs-attribute">constructor</span>: <span class="hljs-function"><span class="hljs-params">(<span class="hljs-property">@attempt</span>, <span class="hljs-property">@errorVariable</span>, <span class="hljs-property">@recovery</span>, <span class="hljs-property">@ensure</span>)</span> -></span>
<span class="hljs-attribute">children</span>: [<span class="hljs-string">'attempt'</span>, <span class="hljs-string">'recovery'</span>, <span class="hljs-string">'ensure'</span>]
<span class="hljs-attribute">isStatement</span>: YES
<span class="hljs-attribute">jumps</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span> <span class="hljs-property">@attempt</span>.jumps(o) <span class="hljs-keyword">or</span> <span class="hljs-property">@recovery</span>?.jumps(o)
<span class="hljs-attribute">makeReturn</span>: <span class="hljs-function"><span class="hljs-params">(res)</span> -></span>
<span class="hljs-property">@attempt</span> = <span class="hljs-property">@attempt</span> .makeReturn res <span class="hljs-keyword">if</span> <span class="hljs-property">@attempt</span>
<span class="hljs-property">@recovery</span> = <span class="hljs-property">@recovery</span>.makeReturn res <span class="hljs-keyword">if</span> <span class="hljs-property">@recovery</span>
<span class="hljs-keyword">this</span></pre></div></div>
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<p>Compilation is more or less as you would expect — the <em>finally</em> clause
is optional, the <em>catch</em> is not.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">compileNode</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
o.indent += TAB
tryPart = <span class="hljs-property">@attempt</span>.compileToFragments o, LEVEL_TOP
catchPart = <span class="hljs-keyword">if</span> <span class="hljs-property">@recovery</span>
generatedErrorVariableName = o.scope.freeVariable <span class="hljs-string">'error'</span>
placeholder = <span class="hljs-keyword">new</span> Literal generatedErrorVariableName
<span class="hljs-property">@recovery</span>.unshift <span class="hljs-keyword">new</span> Assign <span class="hljs-property">@errorVariable</span>, placeholder <span class="hljs-keyword">if</span> <span class="hljs-property">@errorVariable</span>
[].concat <span class="hljs-property">@makeCode</span>(<span class="hljs-string">" catch ("</span>), placeholder.compileToFragments(o), <span class="hljs-property">@makeCode</span>(<span class="hljs-string">") {\n"</span>),
<span class="hljs-property">@recovery</span>.compileToFragments(o, LEVEL_TOP), <span class="hljs-property">@makeCode</span>(<span class="hljs-string">"\n<span class="hljs-subst">#{<span class="hljs-property">@tab</span>}</span>}"</span>)
<span class="hljs-keyword">else</span> <span class="hljs-keyword">unless</span> <span class="hljs-property">@ensure</span> <span class="hljs-keyword">or</span> <span class="hljs-property">@recovery</span>
[<span class="hljs-property">@makeCode</span>(<span class="hljs-string">" catch (<span class="hljs-subst">#{generatedErrorVariableName}</span>) {}"</span>)]
<span class="hljs-keyword">else</span>
[]
ensurePart = <span class="hljs-keyword">if</span> <span class="hljs-property">@ensure</span> <span class="hljs-keyword">then</span> ([].concat <span class="hljs-property">@makeCode</span>(<span class="hljs-string">" finally {\n"</span>), <span class="hljs-property">@ensure</span>.compileToFragments(o, LEVEL_TOP),
<span class="hljs-property">@makeCode</span>(<span class="hljs-string">"\n<span class="hljs-subst">#{<span class="hljs-property">@tab</span>}</span>}"</span>)) <span class="hljs-keyword">else</span> []
[].concat <span class="hljs-property">@makeCode</span>(<span class="hljs-string">"<span class="hljs-subst">#{<span class="hljs-property">@tab</span>}</span>try {\n"</span>),
tryPart,
<span class="hljs-property">@makeCode</span>(<span class="hljs-string">"\n<span class="hljs-subst">#{<span class="hljs-property">@tab</span>}</span>}"</span>), catchPart, ensurePart</pre></div></div>
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<h3 id="throw">Throw</h3>
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<p>Simple node to throw an exception.</p>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.Throw = <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">Throw</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">Base</span></span>
<span class="hljs-attribute">constructor</span>: <span class="hljs-function"><span class="hljs-params">(<span class="hljs-property">@expression</span>)</span> -></span>
<span class="hljs-attribute">children</span>: [<span class="hljs-string">'expression'</span>]
<span class="hljs-attribute">isStatement</span>: YES
<span class="hljs-attribute">jumps</span>: NO</pre></div></div>
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<p>A <strong>Throw</strong> is already a return, of sorts…</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">makeReturn</span>: THIS
<span class="hljs-attribute">compileNode</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
[].concat <span class="hljs-property">@makeCode</span>(<span class="hljs-property">@tab</span> + <span class="hljs-string">"throw "</span>), <span class="hljs-property">@expression</span>.compileToFragments(o), <span class="hljs-property">@makeCode</span>(<span class="hljs-string">";"</span>)</pre></div></div>
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<h3 id="existence">Existence</h3>
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<p>Checks a variable for existence — not <em>null</em> and not <em>undefined</em>. This is
similar to <code>.nil?</code> in Ruby, and avoids having to consult a JavaScript truth
table.</p>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.Existence = <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">Existence</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">Base</span></span>
<span class="hljs-attribute">constructor</span>: <span class="hljs-function"><span class="hljs-params">(<span class="hljs-property">@expression</span>)</span> -></span>
<span class="hljs-attribute">children</span>: [<span class="hljs-string">'expression'</span>]
<span class="hljs-attribute">invert</span>: NEGATE
<span class="hljs-attribute">compileNode</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
<span class="hljs-property">@expression</span>.front = <span class="hljs-property">@front</span>
code = <span class="hljs-property">@expression</span>.compile o, LEVEL_OP
<span class="hljs-keyword">if</span> IDENTIFIER.test(code) <span class="hljs-keyword">and</span> <span class="hljs-keyword">not</span> o.scope.check code
[cmp, cnj] = <span class="hljs-keyword">if</span> <span class="hljs-property">@negated</span> <span class="hljs-keyword">then</span> [<span class="hljs-string">'==='</span>, <span class="hljs-string">'||'</span>] <span class="hljs-keyword">else</span> [<span class="hljs-string">'!=='</span>, <span class="hljs-string">'&&'</span>]
code = <span class="hljs-string">"typeof <span class="hljs-subst">#{code}</span> <span class="hljs-subst">#{cmp}</span> \"undefined\" <span class="hljs-subst">#{cnj}</span> <span class="hljs-subst">#{code}</span> <span class="hljs-subst">#{cmp}</span> null"</span>
<span class="hljs-keyword">else</span></pre></div></div>
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<p>do not use strict equality here; it will break existing code</p>
</div>
<div class="content"><div class='highlight'><pre> code = <span class="hljs-string">"<span class="hljs-subst">#{code}</span> <span class="hljs-subst">#{<span class="hljs-keyword">if</span> <span class="hljs-property">@negated</span> <span class="hljs-keyword">then</span> <span class="hljs-string">'=='</span> <span class="hljs-keyword">else</span> <span class="hljs-string">'!='</span>}</span> null"</span>
[<span class="hljs-property">@makeCode</span>(<span class="hljs-keyword">if</span> o.level <= LEVEL_COND <span class="hljs-keyword">then</span> code <span class="hljs-keyword">else</span> <span class="hljs-string">"(<span class="hljs-subst">#{code}</span>)"</span>)]</pre></div></div>
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<h3 id="parens">Parens</h3>
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<p>An extra set of parentheses, specified explicitly in the source. At one time
we tried to clean up the results by detecting and removing redundant
parentheses, but no longer — you can put in as many as you please.</p>
<p>Parentheses are a good way to force any statement to become an expression.</p>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.Parens = <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">Parens</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">Base</span></span>
<span class="hljs-attribute">constructor</span>: <span class="hljs-function"><span class="hljs-params">(<span class="hljs-property">@body</span>)</span> -></span>
<span class="hljs-attribute">children</span>: [<span class="hljs-string">'body'</span>]
unwrap :<span class="hljs-function"> -></span> <span class="hljs-property">@body</span>
isComplex :<span class="hljs-function"> -></span> <span class="hljs-property">@body</span>.isComplex()
<span class="hljs-attribute">compileNode</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
expr = <span class="hljs-property">@body</span>.unwrap()
<span class="hljs-keyword">if</span> expr <span class="hljs-keyword">instanceof</span> Value <span class="hljs-keyword">and</span> expr.isAtomic()
expr.front = <span class="hljs-property">@front</span>
<span class="hljs-keyword">return</span> expr.compileToFragments o
fragments = expr.compileToFragments o, LEVEL_PAREN
bare = o.level < LEVEL_OP <span class="hljs-keyword">and</span> (expr <span class="hljs-keyword">instanceof</span> Op <span class="hljs-keyword">or</span> expr <span class="hljs-keyword">instanceof</span> Call <span class="hljs-keyword">or</span>
(expr <span class="hljs-keyword">instanceof</span> For <span class="hljs-keyword">and</span> expr.returns))
<span class="hljs-keyword">if</span> bare <span class="hljs-keyword">then</span> fragments <span class="hljs-keyword">else</span> <span class="hljs-property">@wrapInBraces</span> fragments</pre></div></div>
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<h3 id="for">For</h3>
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<p>CoffeeScript’s replacement for the <em>for</em> loop is our array and object
comprehensions, that compile into <em>for</em> loops here. They also act as an
expression, able to return the result of each filtered iteration.</p>
<p>Unlike Python array comprehensions, they can be multi-line, and you can pass
the current index of the loop as a second parameter. Unlike Ruby blocks,
you can map and filter in a single pass.</p>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.For = <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">For</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">While</span></span>
<span class="hljs-attribute">constructor</span>: <span class="hljs-function"><span class="hljs-params">(body, source)</span> -></span>
{<span class="hljs-property">@source</span>, <span class="hljs-property">@guard</span>, <span class="hljs-property">@step</span>, <span class="hljs-property">@name</span>, <span class="hljs-property">@index</span>} = source
<span class="hljs-property">@body</span> = Block.wrap [body]
<span class="hljs-property">@own</span> = !!source.own
<span class="hljs-property">@object</span> = !!source.object
[<span class="hljs-property">@name</span>, <span class="hljs-property">@index</span>] = [<span class="hljs-property">@index</span>, <span class="hljs-property">@name</span>] <span class="hljs-keyword">if</span> <span class="hljs-property">@object</span>
<span class="hljs-property">@index</span>.error <span class="hljs-string">'index cannot be a pattern matching expression'</span> <span class="hljs-keyword">if</span> <span class="hljs-property">@index</span> <span class="hljs-keyword">instanceof</span> Value
<span class="hljs-property">@range</span> = <span class="hljs-property">@source</span> <span class="hljs-keyword">instanceof</span> Value <span class="hljs-keyword">and</span> <span class="hljs-property">@source</span>.base <span class="hljs-keyword">instanceof</span> Range <span class="hljs-keyword">and</span> <span class="hljs-keyword">not</span> <span class="hljs-property">@source</span>.properties.length
<span class="hljs-property">@pattern</span> = <span class="hljs-property">@name</span> <span class="hljs-keyword">instanceof</span> Value
<span class="hljs-property">@index</span>.error <span class="hljs-string">'indexes do not apply to range loops'</span> <span class="hljs-keyword">if</span> <span class="hljs-property">@range</span> <span class="hljs-keyword">and</span> <span class="hljs-property">@index</span>
<span class="hljs-property">@name</span>.error <span class="hljs-string">'cannot pattern match over range loops'</span> <span class="hljs-keyword">if</span> <span class="hljs-property">@range</span> <span class="hljs-keyword">and</span> <span class="hljs-property">@pattern</span>
<span class="hljs-property">@name</span>.error <span class="hljs-string">'cannot use own with for-in'</span> <span class="hljs-keyword">if</span> <span class="hljs-property">@own</span> <span class="hljs-keyword">and</span> <span class="hljs-keyword">not</span> <span class="hljs-property">@object</span>
<span class="hljs-property">@returns</span> = <span class="hljs-literal">false</span>
<span class="hljs-attribute">children</span>: [<span class="hljs-string">'body'</span>, <span class="hljs-string">'source'</span>, <span class="hljs-string">'guard'</span>, <span class="hljs-string">'step'</span>]</pre></div></div>
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<p>Welcome to the hairiest method in all of CoffeeScript. Handles the inner
loop, filtering, stepping, and result saving for array, object, and range
comprehensions. Some of the generated code can be shared in common, and
some cannot.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">compileNode</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
body = Block.wrap [<span class="hljs-property">@body</span>]
[..., last] = body.expressions
<span class="hljs-property">@returns</span> = <span class="hljs-literal">no</span> <span class="hljs-keyword">if</span> last?.jumps() <span class="hljs-keyword">instanceof</span> Return
source = <span class="hljs-keyword">if</span> <span class="hljs-property">@range</span> <span class="hljs-keyword">then</span> <span class="hljs-property">@source</span>.base <span class="hljs-keyword">else</span> <span class="hljs-property">@source</span>
scope = o.scope
name = <span class="hljs-property">@name</span> <span class="hljs-keyword">and</span> (<span class="hljs-property">@name</span>.compile o, LEVEL_LIST) <span class="hljs-keyword">if</span> <span class="hljs-keyword">not</span> <span class="hljs-property">@pattern</span>
index = <span class="hljs-property">@index</span> <span class="hljs-keyword">and</span> (<span class="hljs-property">@index</span>.compile o, LEVEL_LIST)
scope.find(name) <span class="hljs-keyword">if</span> name <span class="hljs-keyword">and</span> <span class="hljs-keyword">not</span> <span class="hljs-property">@pattern</span>
scope.find(index) <span class="hljs-keyword">if</span> index
rvar = scope.freeVariable <span class="hljs-string">'results'</span> <span class="hljs-keyword">if</span> <span class="hljs-property">@returns</span>
ivar = (<span class="hljs-property">@object</span> <span class="hljs-keyword">and</span> index) <span class="hljs-keyword">or</span> scope.freeVariable <span class="hljs-string">'i'</span>, <span class="hljs-attribute">single</span>: <span class="hljs-literal">true</span>
kvar = (<span class="hljs-property">@range</span> <span class="hljs-keyword">and</span> name) <span class="hljs-keyword">or</span> index <span class="hljs-keyword">or</span> ivar
kvarAssign = <span class="hljs-keyword">if</span> kvar <span class="hljs-keyword">isnt</span> ivar <span class="hljs-keyword">then</span> <span class="hljs-string">"<span class="hljs-subst">#{kvar}</span> = "</span> <span class="hljs-keyword">else</span> <span class="hljs-string">""</span>
<span class="hljs-keyword">if</span> <span class="hljs-property">@step</span> <span class="hljs-keyword">and</span> <span class="hljs-keyword">not</span> <span class="hljs-property">@range</span>
[step, stepVar] = <span class="hljs-property">@cacheToCodeFragments</span> <span class="hljs-property">@step</span>.cache o, LEVEL_LIST, isComplexOrAssignable
stepNum = stepVar.match NUMBER
name = ivar <span class="hljs-keyword">if</span> <span class="hljs-property">@pattern</span>
varPart = <span class="hljs-string">''</span>
guardPart = <span class="hljs-string">''</span>
defPart = <span class="hljs-string">''</span>
idt1 = <span class="hljs-property">@tab</span> + TAB
<span class="hljs-keyword">if</span> <span class="hljs-property">@range</span>
forPartFragments = source.compileToFragments merge o,
{<span class="hljs-attribute">index</span>: ivar, name, <span class="hljs-property">@step</span>, <span class="hljs-attribute">isComplex</span>: isComplexOrAssignable}
<span class="hljs-keyword">else</span>
svar = <span class="hljs-property">@source</span>.compile o, LEVEL_LIST
<span class="hljs-keyword">if</span> (name <span class="hljs-keyword">or</span> <span class="hljs-property">@own</span>) <span class="hljs-keyword">and</span> <span class="hljs-keyword">not</span> IDENTIFIER.test svar
defPart += <span class="hljs-string">"<span class="hljs-subst">#{<span class="hljs-property">@tab</span>}</span><span class="hljs-subst">#{ref = scope.freeVariable <span class="hljs-string">'ref'</span>}</span> = <span class="hljs-subst">#{svar}</span>;\n"</span>
svar = ref
<span class="hljs-keyword">if</span> name <span class="hljs-keyword">and</span> <span class="hljs-keyword">not</span> <span class="hljs-property">@pattern</span>
namePart = <span class="hljs-string">"<span class="hljs-subst">#{name}</span> = <span class="hljs-subst">#{svar}</span>[<span class="hljs-subst">#{kvar}</span>]"</span>
<span class="hljs-keyword">if</span> <span class="hljs-keyword">not</span> <span class="hljs-property">@object</span>
defPart += <span class="hljs-string">"<span class="hljs-subst">#{<span class="hljs-property">@tab</span>}</span><span class="hljs-subst">#{step}</span>;\n"</span> <span class="hljs-keyword">if</span> step <span class="hljs-keyword">isnt</span> stepVar
lvar = scope.freeVariable <span class="hljs-string">'len'</span> <span class="hljs-keyword">unless</span> <span class="hljs-property">@step</span> <span class="hljs-keyword">and</span> stepNum <span class="hljs-keyword">and</span> down = (parseNum(stepNum[<span class="hljs-number">0</span>]) < <span class="hljs-number">0</span>)
declare = <span class="hljs-string">"<span class="hljs-subst">#{kvarAssign}</span><span class="hljs-subst">#{ivar}</span> = 0, <span class="hljs-subst">#{lvar}</span> = <span class="hljs-subst">#{svar}</span>.length"</span>
declareDown = <span class="hljs-string">"<span class="hljs-subst">#{kvarAssign}</span><span class="hljs-subst">#{ivar}</span> = <span class="hljs-subst">#{svar}</span>.length - 1"</span>
compare = <span class="hljs-string">"<span class="hljs-subst">#{ivar}</span> < <span class="hljs-subst">#{lvar}</span>"</span>
compareDown = <span class="hljs-string">"<span class="hljs-subst">#{ivar}</span> >= 0"</span>
<span class="hljs-keyword">if</span> <span class="hljs-property">@step</span>
<span class="hljs-keyword">if</span> stepNum
<span class="hljs-keyword">if</span> down
compare = compareDown
declare = declareDown
<span class="hljs-keyword">else</span>
compare = <span class="hljs-string">"<span class="hljs-subst">#{stepVar}</span> > 0 ? <span class="hljs-subst">#{compare}</span> : <span class="hljs-subst">#{compareDown}</span>"</span>
declare = <span class="hljs-string">"(<span class="hljs-subst">#{stepVar}</span> > 0 ? (<span class="hljs-subst">#{declare}</span>) : <span class="hljs-subst">#{declareDown}</span>)"</span>
increment = <span class="hljs-string">"<span class="hljs-subst">#{ivar}</span> += <span class="hljs-subst">#{stepVar}</span>"</span>
<span class="hljs-keyword">else</span>
increment = <span class="hljs-string">"<span class="hljs-subst">#{<span class="hljs-keyword">if</span> kvar <span class="hljs-keyword">isnt</span> ivar <span class="hljs-keyword">then</span> <span class="hljs-string">"++<span class="hljs-subst">#{ivar}</span>"</span> <span class="hljs-keyword">else</span> <span class="hljs-string">"<span class="hljs-subst">#{ivar}</span>++"</span>}</span>"</span>
forPartFragments = [<span class="hljs-property">@makeCode</span>(<span class="hljs-string">"<span class="hljs-subst">#{declare}</span>; <span class="hljs-subst">#{compare}</span>; <span class="hljs-subst">#{kvarAssign}</span><span class="hljs-subst">#{increment}</span>"</span>)]
<span class="hljs-keyword">if</span> <span class="hljs-property">@returns</span>
resultPart = <span class="hljs-string">"<span class="hljs-subst">#{<span class="hljs-property">@tab</span>}</span><span class="hljs-subst">#{rvar}</span> = [];\n"</span>
returnResult = <span class="hljs-string">"\n<span class="hljs-subst">#{<span class="hljs-property">@tab</span>}</span>return <span class="hljs-subst">#{rvar}</span>;"</span>
body.makeReturn rvar
<span class="hljs-keyword">if</span> <span class="hljs-property">@guard</span>
<span class="hljs-keyword">if</span> body.expressions.length > <span class="hljs-number">1</span>
body.expressions.unshift <span class="hljs-keyword">new</span> If (<span class="hljs-keyword">new</span> Parens <span class="hljs-property">@guard</span>).invert(), <span class="hljs-keyword">new</span> Literal <span class="hljs-string">"continue"</span>
<span class="hljs-keyword">else</span>
body = Block.wrap [<span class="hljs-keyword">new</span> If <span class="hljs-property">@guard</span>, body] <span class="hljs-keyword">if</span> <span class="hljs-property">@guard</span>
<span class="hljs-keyword">if</span> <span class="hljs-property">@pattern</span>
body.expressions.unshift <span class="hljs-keyword">new</span> Assign <span class="hljs-property">@name</span>, <span class="hljs-keyword">new</span> Literal <span class="hljs-string">"<span class="hljs-subst">#{svar}</span>[<span class="hljs-subst">#{kvar}</span>]"</span>
defPartFragments = [].concat <span class="hljs-property">@makeCode</span>(defPart), <span class="hljs-property">@pluckDirectCall</span>(o, body)
varPart = <span class="hljs-string">"\n<span class="hljs-subst">#{idt1}</span><span class="hljs-subst">#{namePart}</span>;"</span> <span class="hljs-keyword">if</span> namePart
<span class="hljs-keyword">if</span> <span class="hljs-property">@object</span>
forPartFragments = [<span class="hljs-property">@makeCode</span>(<span class="hljs-string">"<span class="hljs-subst">#{kvar}</span> in <span class="hljs-subst">#{svar}</span>"</span>)]
guardPart = <span class="hljs-string">"\n<span class="hljs-subst">#{idt1}</span>if (!<span class="hljs-subst">#{utility <span class="hljs-string">'hasProp'</span>, o}</span>.call(<span class="hljs-subst">#{svar}</span>, <span class="hljs-subst">#{kvar}</span>)) continue;"</span> <span class="hljs-keyword">if</span> <span class="hljs-property">@own</span>
bodyFragments = body.compileToFragments merge(o, <span class="hljs-attribute">indent</span>: idt1), LEVEL_TOP
<span class="hljs-keyword">if</span> bodyFragments <span class="hljs-keyword">and</span> (bodyFragments.length > <span class="hljs-number">0</span>)
bodyFragments = [].concat <span class="hljs-property">@makeCode</span>(<span class="hljs-string">"\n"</span>), bodyFragments, <span class="hljs-property">@makeCode</span>(<span class="hljs-string">"\n"</span>)
[].concat defPartFragments, <span class="hljs-property">@makeCode</span>(<span class="hljs-string">"<span class="hljs-subst">#{resultPart <span class="hljs-keyword">or</span> <span class="hljs-string">''</span>}</span><span class="hljs-subst">#{<span class="hljs-property">@tab</span>}</span>for ("</span>),
forPartFragments, <span class="hljs-property">@makeCode</span>(<span class="hljs-string">") {<span class="hljs-subst">#{guardPart}</span><span class="hljs-subst">#{varPart}</span>"</span>), bodyFragments,
<span class="hljs-property">@makeCode</span>(<span class="hljs-string">"<span class="hljs-subst">#{<span class="hljs-property">@tab</span>}</span>}<span class="hljs-subst">#{returnResult <span class="hljs-keyword">or</span> <span class="hljs-string">''</span>}</span>"</span>)
<span class="hljs-attribute">pluckDirectCall</span>: <span class="hljs-function"><span class="hljs-params">(o, body)</span> -></span>
defs = []
<span class="hljs-keyword">for</span> expr, idx <span class="hljs-keyword">in</span> body.expressions
expr = expr.unwrapAll()
<span class="hljs-keyword">continue</span> <span class="hljs-keyword">unless</span> expr <span class="hljs-keyword">instanceof</span> Call
val = expr.variable?.unwrapAll()
<span class="hljs-keyword">continue</span> <span class="hljs-keyword">unless</span> (val <span class="hljs-keyword">instanceof</span> Code) <span class="hljs-keyword">or</span>
(val <span class="hljs-keyword">instanceof</span> Value <span class="hljs-keyword">and</span>
val.base?.unwrapAll() <span class="hljs-keyword">instanceof</span> Code <span class="hljs-keyword">and</span>
val.properties.length <span class="hljs-keyword">is</span> <span class="hljs-number">1</span> <span class="hljs-keyword">and</span>
val.properties[<span class="hljs-number">0</span>].name?.value <span class="hljs-keyword">in</span> [<span class="hljs-string">'call'</span>, <span class="hljs-string">'apply'</span>])
fn = val.base?.unwrapAll() <span class="hljs-keyword">or</span> val
ref = <span class="hljs-keyword">new</span> Literal o.scope.freeVariable <span class="hljs-string">'fn'</span>
base = <span class="hljs-keyword">new</span> Value ref
<span class="hljs-keyword">if</span> val.base
[val.base, base] = [base, val]
body.expressions[idx] = <span class="hljs-keyword">new</span> Call base, expr.args
defs = defs.concat <span class="hljs-property">@makeCode</span>(<span class="hljs-property">@tab</span>), (<span class="hljs-keyword">new</span> Assign(ref, fn).compileToFragments(o, LEVEL_TOP)), <span class="hljs-property">@makeCode</span>(<span class="hljs-string">';\n'</span>)
defs</pre></div></div>
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<h3 id="switch">Switch</h3>
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<p>A JavaScript <em>switch</em> statement. Converts into a returnable expression on-demand.</p>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.Switch = <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">Switch</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">Base</span></span>
<span class="hljs-attribute">constructor</span>: <span class="hljs-function"><span class="hljs-params">(<span class="hljs-property">@subject</span>, <span class="hljs-property">@cases</span>, <span class="hljs-property">@otherwise</span>)</span> -></span>
<span class="hljs-attribute">children</span>: [<span class="hljs-string">'subject'</span>, <span class="hljs-string">'cases'</span>, <span class="hljs-string">'otherwise'</span>]
<span class="hljs-attribute">isStatement</span>: YES
<span class="hljs-attribute">jumps</span>: <span class="hljs-function"><span class="hljs-params">(o = {block: <span class="hljs-literal">yes</span>})</span> -></span>
<span class="hljs-keyword">for</span> [conds, block] <span class="hljs-keyword">in</span> <span class="hljs-property">@cases</span>
<span class="hljs-keyword">return</span> jumpNode <span class="hljs-keyword">if</span> jumpNode = block.jumps o
<span class="hljs-property">@otherwise</span>?.jumps o
<span class="hljs-attribute">makeReturn</span>: <span class="hljs-function"><span class="hljs-params">(res)</span> -></span>
pair[<span class="hljs-number">1</span>].makeReturn res <span class="hljs-keyword">for</span> pair <span class="hljs-keyword">in</span> <span class="hljs-property">@cases</span>
<span class="hljs-property">@otherwise</span> <span class="hljs-keyword">or</span>= <span class="hljs-keyword">new</span> Block [<span class="hljs-keyword">new</span> Literal <span class="hljs-string">'void 0'</span>] <span class="hljs-keyword">if</span> res
<span class="hljs-property">@otherwise</span>?.makeReturn res
<span class="hljs-keyword">this</span>
<span class="hljs-attribute">compileNode</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
idt1 = o.indent + TAB
idt2 = o.indent = idt1 + TAB
fragments = [].concat <span class="hljs-property">@makeCode</span>(<span class="hljs-property">@tab</span> + <span class="hljs-string">"switch ("</span>),
(<span class="hljs-keyword">if</span> <span class="hljs-property">@subject</span> <span class="hljs-keyword">then</span> <span class="hljs-property">@subject</span>.compileToFragments(o, LEVEL_PAREN) <span class="hljs-keyword">else</span> <span class="hljs-property">@makeCode</span> <span class="hljs-string">"false"</span>),
<span class="hljs-property">@makeCode</span>(<span class="hljs-string">") {\n"</span>)
<span class="hljs-keyword">for</span> [conditions, block], i <span class="hljs-keyword">in</span> <span class="hljs-property">@cases</span>
<span class="hljs-keyword">for</span> cond <span class="hljs-keyword">in</span> flatten [conditions]
cond = cond.invert() <span class="hljs-keyword">unless</span> <span class="hljs-property">@subject</span>
fragments = fragments.concat <span class="hljs-property">@makeCode</span>(idt1 + <span class="hljs-string">"case "</span>), cond.compileToFragments(o, LEVEL_PAREN), <span class="hljs-property">@makeCode</span>(<span class="hljs-string">":\n"</span>)
fragments = fragments.concat body, <span class="hljs-property">@makeCode</span>(<span class="hljs-string">'\n'</span>) <span class="hljs-keyword">if</span> (body = block.compileToFragments o, LEVEL_TOP).length > <span class="hljs-number">0</span>
<span class="hljs-keyword">break</span> <span class="hljs-keyword">if</span> i <span class="hljs-keyword">is</span> <span class="hljs-property">@cases</span>.length - <span class="hljs-number">1</span> <span class="hljs-keyword">and</span> <span class="hljs-keyword">not</span> <span class="hljs-property">@otherwise</span>
expr = <span class="hljs-property">@lastNonComment</span> block.expressions
<span class="hljs-keyword">continue</span> <span class="hljs-keyword">if</span> expr <span class="hljs-keyword">instanceof</span> Return <span class="hljs-keyword">or</span> (expr <span class="hljs-keyword">instanceof</span> Literal <span class="hljs-keyword">and</span> expr.jumps() <span class="hljs-keyword">and</span> expr.value <span class="hljs-keyword">isnt</span> <span class="hljs-string">'debugger'</span>)
fragments.push cond.makeCode(idt2 + <span class="hljs-string">'break;\n'</span>)
<span class="hljs-keyword">if</span> <span class="hljs-property">@otherwise</span> <span class="hljs-keyword">and</span> <span class="hljs-property">@otherwise</span>.expressions.length
fragments.push <span class="hljs-property">@makeCode</span>(idt1 + <span class="hljs-string">"default:\n"</span>), (<span class="hljs-property">@otherwise</span>.compileToFragments o, LEVEL_TOP)..., <span class="hljs-property">@makeCode</span>(<span class="hljs-string">"\n"</span>)
fragments.push <span class="hljs-property">@makeCode</span> <span class="hljs-property">@tab</span> + <span class="hljs-string">'}'</span>
fragments</pre></div></div>
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<h3 id="if">If</h3>
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<p><em>If/else</em> statements. Acts as an expression by pushing down requested returns
to the last line of each clause.</p>
<p>Single-expression <strong>Ifs</strong> are compiled into conditional operators if possible,
because ternaries are already proper expressions, and don’t need conversion.</p>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.If = <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">If</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">Base</span></span>
<span class="hljs-attribute">constructor</span>: <span class="hljs-function"><span class="hljs-params">(condition, <span class="hljs-property">@body</span>, options = {})</span> -></span>
<span class="hljs-property">@condition</span> = <span class="hljs-keyword">if</span> options.type <span class="hljs-keyword">is</span> <span class="hljs-string">'unless'</span> <span class="hljs-keyword">then</span> condition.invert() <span class="hljs-keyword">else</span> condition
<span class="hljs-property">@elseBody</span> = <span class="hljs-literal">null</span>
<span class="hljs-property">@isChain</span> = <span class="hljs-literal">false</span>
{<span class="hljs-property">@soak</span>} = options
<span class="hljs-attribute">children</span>: [<span class="hljs-string">'condition'</span>, <span class="hljs-string">'body'</span>, <span class="hljs-string">'elseBody'</span>]
<span class="hljs-attribute">bodyNode</span>:<span class="hljs-function"> -></span> <span class="hljs-property">@body</span>?.unwrap()
<span class="hljs-attribute">elseBodyNode</span>:<span class="hljs-function"> -></span> <span class="hljs-property">@elseBody</span>?.unwrap()</pre></div></div>
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<p>Rewrite a chain of <strong>Ifs</strong> to add a default case as the final <em>else</em>.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">addElse</span>: <span class="hljs-function"><span class="hljs-params">(elseBody)</span> -></span>
<span class="hljs-keyword">if</span> <span class="hljs-property">@isChain</span>
<span class="hljs-property">@elseBodyNode</span>().addElse elseBody
<span class="hljs-keyword">else</span>
<span class="hljs-property">@isChain</span> = elseBody <span class="hljs-keyword">instanceof</span> If
<span class="hljs-property">@elseBody</span> = <span class="hljs-property">@ensureBlock</span> elseBody
<span class="hljs-property">@elseBody</span>.updateLocationDataIfMissing elseBody.locationData
<span class="hljs-keyword">this</span></pre></div></div>
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<p>The <strong>If</strong> only compiles into a statement if either of its bodies needs
to be a statement. Otherwise a conditional operator is safe.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">isStatement</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
o?.level <span class="hljs-keyword">is</span> LEVEL_TOP <span class="hljs-keyword">or</span>
<span class="hljs-property">@bodyNode</span>().isStatement(o) <span class="hljs-keyword">or</span> <span class="hljs-property">@elseBodyNode</span>()?.isStatement(o)
<span class="hljs-attribute">jumps</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span> <span class="hljs-property">@body</span>.jumps(o) <span class="hljs-keyword">or</span> <span class="hljs-property">@elseBody</span>?.jumps(o)
<span class="hljs-attribute">compileNode</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
<span class="hljs-keyword">if</span> <span class="hljs-property">@isStatement</span> o <span class="hljs-keyword">then</span> <span class="hljs-property">@compileStatement</span> o <span class="hljs-keyword">else</span> <span class="hljs-property">@compileExpression</span> o
<span class="hljs-attribute">makeReturn</span>: <span class="hljs-function"><span class="hljs-params">(res)</span> -></span>
<span class="hljs-property">@elseBody</span> <span class="hljs-keyword">or</span>= <span class="hljs-keyword">new</span> Block [<span class="hljs-keyword">new</span> Literal <span class="hljs-string">'void 0'</span>] <span class="hljs-keyword">if</span> res
<span class="hljs-property">@body</span> <span class="hljs-keyword">and</span>= <span class="hljs-keyword">new</span> Block [<span class="hljs-property">@body</span>.makeReturn res]
<span class="hljs-property">@elseBody</span> <span class="hljs-keyword">and</span>= <span class="hljs-keyword">new</span> Block [<span class="hljs-property">@elseBody</span>.makeReturn res]
<span class="hljs-keyword">this</span>
<span class="hljs-attribute">ensureBlock</span>: <span class="hljs-function"><span class="hljs-params">(node)</span> -></span>
<span class="hljs-keyword">if</span> node <span class="hljs-keyword">instanceof</span> Block <span class="hljs-keyword">then</span> node <span class="hljs-keyword">else</span> <span class="hljs-keyword">new</span> Block [node]</pre></div></div>
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<p>Compile the <code>If</code> as a regular <em>if-else</em> statement. Flattened chains
force inner <em>else</em> bodies into statement form.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">compileStatement</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
child = del o, <span class="hljs-string">'chainChild'</span>
exeq = del o, <span class="hljs-string">'isExistentialEquals'</span>
<span class="hljs-keyword">if</span> exeq
<span class="hljs-keyword">return</span> <span class="hljs-keyword">new</span> If(<span class="hljs-property">@condition</span>.invert(), <span class="hljs-property">@elseBodyNode</span>(), <span class="hljs-attribute">type</span>: <span class="hljs-string">'if'</span>).compileToFragments o
indent = o.indent + TAB
cond = <span class="hljs-property">@condition</span>.compileToFragments o, LEVEL_PAREN
body = <span class="hljs-property">@ensureBlock</span>(<span class="hljs-property">@body</span>).compileToFragments merge o, {indent}
ifPart = [].concat <span class="hljs-property">@makeCode</span>(<span class="hljs-string">"if ("</span>), cond, <span class="hljs-property">@makeCode</span>(<span class="hljs-string">") {\n"</span>), body, <span class="hljs-property">@makeCode</span>(<span class="hljs-string">"\n<span class="hljs-subst">#{<span class="hljs-property">@tab</span>}</span>}"</span>)
ifPart.unshift <span class="hljs-property">@makeCode</span> <span class="hljs-property">@tab</span> <span class="hljs-keyword">unless</span> child
<span class="hljs-keyword">return</span> ifPart <span class="hljs-keyword">unless</span> <span class="hljs-property">@elseBody</span>
answer = ifPart.concat <span class="hljs-property">@makeCode</span>(<span class="hljs-string">' else '</span>)
<span class="hljs-keyword">if</span> <span class="hljs-property">@isChain</span>
o.chainChild = <span class="hljs-literal">yes</span>
answer = answer.concat <span class="hljs-property">@elseBody</span>.unwrap().compileToFragments o, LEVEL_TOP
<span class="hljs-keyword">else</span>
answer = answer.concat <span class="hljs-property">@makeCode</span>(<span class="hljs-string">"{\n"</span>), <span class="hljs-property">@elseBody</span>.compileToFragments(merge(o, {indent}), LEVEL_TOP), <span class="hljs-property">@makeCode</span>(<span class="hljs-string">"\n<span class="hljs-subst">#{<span class="hljs-property">@tab</span>}</span>}"</span>)
answer</pre></div></div>
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<p>Compile the <code>If</code> as a conditional operator.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">compileExpression</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span>
cond = <span class="hljs-property">@condition</span>.compileToFragments o, LEVEL_COND
body = <span class="hljs-property">@bodyNode</span>().compileToFragments o, LEVEL_LIST
alt = <span class="hljs-keyword">if</span> <span class="hljs-property">@elseBodyNode</span>() <span class="hljs-keyword">then</span> <span class="hljs-property">@elseBodyNode</span>().compileToFragments(o, LEVEL_LIST) <span class="hljs-keyword">else</span> [<span class="hljs-property">@makeCode</span>(<span class="hljs-string">'void 0'</span>)]
fragments = cond.concat <span class="hljs-property">@makeCode</span>(<span class="hljs-string">" ? "</span>), body, <span class="hljs-property">@makeCode</span>(<span class="hljs-string">" : "</span>), alt
<span class="hljs-keyword">if</span> o.level >= LEVEL_COND <span class="hljs-keyword">then</span> <span class="hljs-property">@wrapInBraces</span> fragments <span class="hljs-keyword">else</span> fragments
<span class="hljs-attribute">unfoldSoak</span>:<span class="hljs-function"> -></span>
<span class="hljs-property">@soak</span> <span class="hljs-keyword">and</span> <span class="hljs-keyword">this</span></pre></div></div>
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<h2 id="constants">Constants</h2>
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<div class="content"><div class='highlight'><pre>
UTILITIES =</pre></div></div>
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<p>Correctly set up a prototype chain for inheritance, including a reference
to the superclass for <code>super()</code> calls, and copies of any static properties.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">extend</span>: <span class="hljs-function"><span class="hljs-params">(o)</span> -></span> <span class="hljs-string">"
function(child, parent) {
for (var key in parent) {
if (<span class="hljs-subst">#{utility <span class="hljs-string">'hasProp'</span>, o}</span>.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;
}
"</span></pre></div></div>
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<p>Create a function bound to the current value of “this”.</p>
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<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">bind</span>:<span class="hljs-function"> -></span> <span class="hljs-string">'
function(fn, me){
return function(){
return fn.apply(me, arguments);
};
}
'</span></pre></div></div>
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<p>Discover if an item is in an array.</p>
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<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">indexOf</span>:<span class="hljs-function"> -></span> <span class="hljs-string">"
[].indexOf || function(item) {
for (var i = 0, l = this.length; i < l; i++) {
if (i in this && this[i] === item) return i;
}
return -1;
}
"</span>
<span class="hljs-attribute">modulo</span>:<span class="hljs-function"> -></span> <span class="hljs-string">"""
function(a, b) { return (+a % (b = +b) + b) % b; }
"""</span></pre></div></div>
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<p>Shortcuts to speed up the lookup time for native functions.</p>
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<div class="content"><div class='highlight'><pre> <span class="hljs-attribute">hasProp</span>:<span class="hljs-function"> -></span> <span class="hljs-string">'{}.hasOwnProperty'</span>
slice :<span class="hljs-function"> -></span> <span class="hljs-string">'[].slice'</span></pre></div></div>
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<p>Levels indicate a node’s position in the AST. Useful for knowing if
parens are necessary or superfluous.</p>
</div>
<div class="content"><div class='highlight'><pre>LEVEL_TOP = <span class="hljs-number">1</span> <span class="hljs-comment"># ...;</span>
LEVEL_PAREN = <span class="hljs-number">2</span> <span class="hljs-comment"># (...)</span>
LEVEL_LIST = <span class="hljs-number">3</span> <span class="hljs-comment"># [...]</span>
LEVEL_COND = <span class="hljs-number">4</span> <span class="hljs-comment"># ... ? x : y</span>
LEVEL_OP = <span class="hljs-number">5</span> <span class="hljs-comment"># !...</span>
LEVEL_ACCESS = <span class="hljs-number">6</span> <span class="hljs-comment"># ...[0]</span></pre></div></div>
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<p>Tabs are two spaces for pretty printing.</p>
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<div class="content"><div class='highlight'><pre>TAB = <span class="hljs-string">' '</span>
IDENTIFIER = <span class="hljs-regexp">/// ^ (?!\d) [$\w\x7f-\uffff]+ $ ///</span>
SIMPLENUM = <span class="hljs-regexp">/^[+-]?\d+$/</span>
HEXNUM = <span class="hljs-regexp">/^[+-]?0x[\da-f]+/i</span>
NUMBER = <span class="hljs-regexp">///^[+-]?(?:
0x[\da-f]+ | <span class="hljs-comment"># hex</span>
\d*\.?\d+ (?:e[+-]?\d+)? <span class="hljs-comment"># decimal</span>
)$///</span>i</pre></div></div>
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<p>Is a literal value a string/regex?</p>
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<div class="content"><div class='highlight'><pre>IS_STRING = <span class="hljs-regexp">/^['"]/</span>
IS_REGEX = <span class="hljs-regexp">/^\//</span></pre></div></div>
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<h2 id="helper-functions">Helper Functions</h2>
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<p>Helper for ensuring that utility functions are assigned at the top level.</p>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-function"><span class="hljs-title">utility</span> = <span class="hljs-params">(name, o)</span> -></span>
{root} = o.scope
<span class="hljs-keyword">if</span> name <span class="hljs-keyword">of</span> root.utilities
root.utilities[name]
<span class="hljs-keyword">else</span>
ref = root.freeVariable name
root.assign ref, UTILITIES[name] o
root.utilities[name] = ref
<span class="hljs-function"><span class="hljs-title">multident</span> = <span class="hljs-params">(code, tab)</span> -></span>
code = code.replace <span class="hljs-regexp">/\n/g</span>, <span class="hljs-string">'$&'</span> + tab
code.replace <span class="hljs-regexp">/\s+$/</span>, <span class="hljs-string">''</span></pre></div></div>
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<p>Parse a number (+- decimal/hexadecimal)
Examples: 0, -1, 1, 2e3, 2e-3, -0xfe, 0xfe</p>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-function"><span class="hljs-title">parseNum</span> = <span class="hljs-params">(x)</span> -></span>
<span class="hljs-keyword">if</span> <span class="hljs-keyword">not</span> x?
<span class="hljs-number">0</span>
<span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> x.match HEXNUM
parseInt x, <span class="hljs-number">16</span>
<span class="hljs-keyword">else</span>
parseFloat x
<span class="hljs-function"><span class="hljs-title">isLiteralArguments</span> = <span class="hljs-params">(node)</span> -></span>
node <span class="hljs-keyword">instanceof</span> Literal <span class="hljs-keyword">and</span> node.value <span class="hljs-keyword">is</span> <span class="hljs-string">'arguments'</span> <span class="hljs-keyword">and</span> <span class="hljs-keyword">not</span> node.asKey
<span class="hljs-function"><span class="hljs-title">isLiteralThis</span> = <span class="hljs-params">(node)</span> -></span>
(node <span class="hljs-keyword">instanceof</span> Literal <span class="hljs-keyword">and</span> node.value <span class="hljs-keyword">is</span> <span class="hljs-string">'this'</span> <span class="hljs-keyword">and</span> <span class="hljs-keyword">not</span> node.asKey) <span class="hljs-keyword">or</span>
(node <span class="hljs-keyword">instanceof</span> Code <span class="hljs-keyword">and</span> node.bound) <span class="hljs-keyword">or</span>
(node <span class="hljs-keyword">instanceof</span> Call <span class="hljs-keyword">and</span> node.isSuper)
<span class="hljs-function"><span class="hljs-title">isComplexOrAssignable</span> = <span class="hljs-params">(node)</span> -></span> node.isComplex() <span class="hljs-keyword">or</span> node.isAssignable?()</pre></div></div>
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<p>Unfold a node’s child if soak, then tuck the node under created <code>If</code></p>
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<div class="content"><div class='highlight'><pre><span class="hljs-function"><span class="hljs-title">unfoldSoak</span> = <span class="hljs-params">(o, parent, name)</span> -></span>
<span class="hljs-keyword">return</span> <span class="hljs-keyword">unless</span> ifn = parent[name].unfoldSoak o
parent[name] = ifn.body
ifn.body = <span class="hljs-keyword">new</span> Value parent
ifn</pre></div></div>
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