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<!DOCTYPE html>
<html>
<head>
<title>helpers.coffee</title>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
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<ul class="sections">
<li id="title">
<div class="annotation">
<h1>helpers.coffee</h1>
</div>
</li>
<li id="section-1">
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<p>This file contains the common helper functions that wed like to share among
the <strong>Lexer</strong>, <strong>Rewriter</strong>, and the <strong>Nodes</strong>. Merge objects, flatten
arrays, count characters, that sort of thing.</p>
</div>
</li>
<li id="section-2">
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<p>Peek at the beginning of a given string to see if it matches a sequence.</p>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.<span class="hljs-function"><span class="hljs-title">starts</span> = <span class="hljs-params">(string, literal, start)</span> -&gt;</span>
literal <span class="hljs-keyword">is</span> string.substr start, literal.length</pre></div></div>
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<p>Peek at the end of a given string to see if it matches a sequence.</p>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.<span class="hljs-function"><span class="hljs-title">ends</span> = <span class="hljs-params">(string, literal, back)</span> -&gt;</span>
len = literal.length
literal <span class="hljs-keyword">is</span> string.substr string.length - len - (back <span class="hljs-keyword">or</span> <span class="hljs-number">0</span>), len</pre></div></div>
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<p>Repeat a string <code>n</code> times.</p>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.repeat = <span class="hljs-function"><span class="hljs-title">repeat</span> = <span class="hljs-params">(str, n)</span> -&gt;</span></pre></div></div>
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<p>Use clever algorithm to have O(log(n)) string concatenation operations.</p>
</div>
<div class="content"><div class='highlight'><pre> res = <span class="hljs-string">''</span>
<span class="hljs-keyword">while</span> n &gt; <span class="hljs-number">0</span>
res += str <span class="hljs-keyword">if</span> n &amp; <span class="hljs-number">1</span>
n &gt;&gt;&gt;= <span class="hljs-number">1</span>
str += str
res</pre></div></div>
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<p>Trim out all falsy values from an array.</p>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.<span class="hljs-function"><span class="hljs-title">compact</span> = <span class="hljs-params">(array)</span> -&gt;</span>
item <span class="hljs-keyword">for</span> item <span class="hljs-keyword">in</span> array <span class="hljs-keyword">when</span> item</pre></div></div>
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<p>Count the number of occurrences of a string in a string.</p>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.<span class="hljs-function"><span class="hljs-title">count</span> = <span class="hljs-params">(string, substr)</span> -&gt;</span>
num = pos = <span class="hljs-number">0</span>
<span class="hljs-keyword">return</span> <span class="hljs-number">1</span>/<span class="hljs-number">0</span> <span class="hljs-keyword">unless</span> substr.length
num++ <span class="hljs-keyword">while</span> pos = <span class="hljs-number">1</span> + string.indexOf substr, pos
num</pre></div></div>
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<p>Merge objects, returning a fresh copy with attributes from both sides.
Used every time <code>Base#compile</code> is called, to allow properties in the
options hash to propagate down the tree without polluting other branches.</p>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.<span class="hljs-function"><span class="hljs-title">merge</span> = <span class="hljs-params">(options, overrides)</span> -&gt;</span>
extend (extend {}, options), overrides</pre></div></div>
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<p>Extend a source object with the properties of another object (shallow copy).</p>
</div>
<div class="content"><div class='highlight'><pre>extend = <span class="hljs-built_in">exports</span>.<span class="hljs-function"><span class="hljs-title">extend</span> = <span class="hljs-params">(object, properties)</span> -&gt;</span>
<span class="hljs-keyword">for</span> key, val <span class="hljs-keyword">of</span> properties
object[key] = val
object</pre></div></div>
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<p>Return a flattened version of an array.
Handy for getting a list of <code>children</code> from the nodes.</p>
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<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.flatten = <span class="hljs-function"><span class="hljs-title">flatten</span> = <span class="hljs-params">(array)</span> -&gt;</span>
flattened = []
<span class="hljs-keyword">for</span> element <span class="hljs-keyword">in</span> array
<span class="hljs-keyword">if</span> element <span class="hljs-keyword">instanceof</span> Array
flattened = flattened.concat flatten element
<span class="hljs-keyword">else</span>
flattened.push element
flattened</pre></div></div>
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<p>Delete a key from an object, returning the value. Useful when a node is
looking for a particular method in an options hash.</p>
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<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.<span class="hljs-function"><span class="hljs-title">del</span> = <span class="hljs-params">(obj, key)</span> -&gt;</span>
val = obj[key]
<span class="hljs-keyword">delete</span> obj[key]
val</pre></div></div>
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<p>Gets the last item of an array(-like) object.</p>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.last = <span class="hljs-function"><span class="hljs-title">last</span> = <span class="hljs-params">(array, back)</span> -&gt;</span> array[array.length - (back <span class="hljs-keyword">or</span> <span class="hljs-number">0</span>) - <span class="hljs-number">1</span>]</pre></div></div>
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<p>Typical Array::some</p>
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<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.some = <span class="hljs-attribute">Array</span>::some ? <span class="hljs-function"><span class="hljs-params">(fn)</span> -&gt;</span>
<span class="hljs-keyword">return</span> <span class="hljs-literal">true</span> <span class="hljs-keyword">for</span> e <span class="hljs-keyword">in</span> <span class="hljs-keyword">this</span> <span class="hljs-keyword">when</span> fn e
<span class="hljs-literal">false</span></pre></div></div>
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<p>Simple function for inverting Literate CoffeeScript code by putting the
documentation in comments, producing a string of CoffeeScript code that
can be compiled “normally”.</p>
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<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.<span class="hljs-function"><span class="hljs-title">invertLiterate</span> = <span class="hljs-params">(code)</span> -&gt;</span>
maybe_code = <span class="hljs-literal">true</span>
lines = <span class="hljs-keyword">for</span> line <span class="hljs-keyword">in</span> code.split(<span class="hljs-string">'\n'</span>)
<span class="hljs-keyword">if</span> maybe_code <span class="hljs-keyword">and</span> <span class="hljs-regexp">/^([ ]{4}|[ ]{0,3}\t)/</span>.test line
line
<span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> maybe_code = <span class="hljs-regexp">/^\s*$/</span>.test line
line
<span class="hljs-keyword">else</span>
<span class="hljs-string">'# '</span> + line
lines.join <span class="hljs-string">'\n'</span></pre></div></div>
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<p>Merge two jison-style location data objects together.
If <code>last</code> is not provided, this will simply return <code>first</code>.</p>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-function"><span class="hljs-title">buildLocationData</span> = <span class="hljs-params">(first, last)</span> -&gt;</span>
<span class="hljs-keyword">if</span> <span class="hljs-keyword">not</span> last
first
<span class="hljs-keyword">else</span>
<span class="hljs-attribute">first_line</span>: first.first_line
<span class="hljs-attribute">first_column</span>: first.first_column
<span class="hljs-attribute">last_line</span>: last.last_line
<span class="hljs-attribute">last_column</span>: last.last_column</pre></div></div>
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<p>This returns a function which takes an object as a parameter, and if that
object is an AST node, updates that objects locationData.
The object is returned either way.</p>
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<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.<span class="hljs-function"><span class="hljs-title">addLocationDataFn</span> = <span class="hljs-params">(first, last)</span> -&gt;</span>
<span class="hljs-function"><span class="hljs-params">(obj)</span> -&gt;</span>
<span class="hljs-keyword">if</span> ((<span class="hljs-keyword">typeof</span> obj) <span class="hljs-keyword">is</span> <span class="hljs-string">'object'</span>) <span class="hljs-keyword">and</span> (!!obj[<span class="hljs-string">'updateLocationDataIfMissing'</span>])
obj.updateLocationDataIfMissing buildLocationData(first, last)
<span class="hljs-keyword">return</span> obj</pre></div></div>
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<p>Convert jison location data to a string.
<code>obj</code> can be a token, or a locationData.</p>
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<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.<span class="hljs-function"><span class="hljs-title">locationDataToString</span> = <span class="hljs-params">(obj)</span> -&gt;</span>
<span class="hljs-keyword">if</span> (<span class="hljs-string">"2"</span> <span class="hljs-keyword">of</span> obj) <span class="hljs-keyword">and</span> (<span class="hljs-string">"first_line"</span> <span class="hljs-keyword">of</span> obj[<span class="hljs-number">2</span>]) <span class="hljs-keyword">then</span> locationData = obj[<span class="hljs-number">2</span>]
<span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> <span class="hljs-string">"first_line"</span> <span class="hljs-keyword">of</span> obj <span class="hljs-keyword">then</span> locationData = obj
<span class="hljs-keyword">if</span> locationData
<span class="hljs-string">"<span class="hljs-subst">#{locationData.first_line + <span class="hljs-number">1</span>}</span>:<span class="hljs-subst">#{locationData.first_column + <span class="hljs-number">1</span>}</span>-"</span> +
<span class="hljs-string">"<span class="hljs-subst">#{locationData.last_line + <span class="hljs-number">1</span>}</span>:<span class="hljs-subst">#{locationData.last_column + <span class="hljs-number">1</span>}</span>"</span>
<span class="hljs-keyword">else</span>
<span class="hljs-string">"No location data"</span></pre></div></div>
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<p>A <code>.coffee.md</code> compatible version of <code>basename</code>, that returns the file sans-extension.</p>
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<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.<span class="hljs-function"><span class="hljs-title">baseFileName</span> = <span class="hljs-params">(file, stripExt = <span class="hljs-literal">no</span>, useWinPathSep = <span class="hljs-literal">no</span>)</span> -&gt;</span>
pathSep = <span class="hljs-keyword">if</span> useWinPathSep <span class="hljs-keyword">then</span> <span class="hljs-regexp">/\\|\//</span> <span class="hljs-keyword">else</span> <span class="hljs-regexp">/\/</span>/
parts = file.split(pathSep)
file = parts[parts.length - <span class="hljs-number">1</span>]
<span class="hljs-keyword">return</span> file <span class="hljs-keyword">unless</span> stripExt <span class="hljs-keyword">and</span> file.indexOf(<span class="hljs-string">'.'</span>) &gt;= <span class="hljs-number">0</span>
parts = file.split(<span class="hljs-string">'.'</span>)
parts.pop()
parts.pop() <span class="hljs-keyword">if</span> parts[parts.length - <span class="hljs-number">1</span>] <span class="hljs-keyword">is</span> <span class="hljs-string">'coffee'</span> <span class="hljs-keyword">and</span> parts.length &gt; <span class="hljs-number">1</span>
parts.join(<span class="hljs-string">'.'</span>)</pre></div></div>
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<p>Determine if a filename represents a CoffeeScript file.</p>
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<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.<span class="hljs-function"><span class="hljs-title">isCoffee</span> = <span class="hljs-params">(file)</span> -&gt;</span> <span class="hljs-regexp">/\.((lit)?coffee|coffee\.md)$/</span>.test file</pre></div></div>
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<p>Determine if a filename represents a Literate CoffeeScript file.</p>
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<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.<span class="hljs-function"><span class="hljs-title">isLiterate</span> = <span class="hljs-params">(file)</span> -&gt;</span> <span class="hljs-regexp">/\.(litcoffee|coffee\.md)$/</span>.test file</pre></div></div>
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<p>Throws a SyntaxError from a given location.
The errors <code>toString</code> will return an error message following the “standard”
format <filename>:<line>:<col>: <message> plus the line with the error and a
marker showing where the error is.</p>
</div>
<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.<span class="hljs-function"><span class="hljs-title">throwSyntaxError</span> = <span class="hljs-params">(message, location)</span> -&gt;</span>
error = <span class="hljs-keyword">new</span> SyntaxError message
error.location = location
error.toString = syntaxErrorToString</pre></div></div>
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<p>Instead of showing the compilers stacktrace, show our custom error message
(this is useful when the error bubbles up in Node.js applications that
compile CoffeeScript for example).</p>
</div>
<div class="content"><div class='highlight'><pre> error.stack = error.toString()
<span class="hljs-keyword">throw</span> error</pre></div></div>
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<p>Update a compiler SyntaxError with source code information if it didnt have
it already.</p>
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<div class="content"><div class='highlight'><pre><span class="hljs-built_in">exports</span>.<span class="hljs-function"><span class="hljs-title">updateSyntaxError</span> = <span class="hljs-params">(error, code, filename)</span> -&gt;</span></pre></div></div>
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<p>Avoid screwing up the <code>stack</code> property of other errors (i.e. possible bugs).</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-keyword">if</span> error.toString <span class="hljs-keyword">is</span> syntaxErrorToString
error.code <span class="hljs-keyword">or</span>= code
error.filename <span class="hljs-keyword">or</span>= filename
error.stack = error.toString()
error
<span class="hljs-function"><span class="hljs-title">syntaxErrorToString</span> = -&gt;</span>
<span class="hljs-keyword">return</span> <span class="hljs-attribute">Error</span>::toString.call @ <span class="hljs-keyword">unless</span> <span class="hljs-property">@code</span> <span class="hljs-keyword">and</span> <span class="hljs-property">@location</span>
{first_line, first_column, last_line, last_column} = <span class="hljs-property">@location</span>
last_line ?= first_line
last_column ?= first_column
filename = <span class="hljs-property">@filename</span> <span class="hljs-keyword">or</span> <span class="hljs-string">'[stdin]'</span>
codeLine = <span class="hljs-property">@code</span>.split(<span class="hljs-string">'\n'</span>)[first_line]
start = first_column</pre></div></div>
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<p>Show only the first line on multi-line errors.</p>
</div>
<div class="content"><div class='highlight'><pre> end = <span class="hljs-keyword">if</span> first_line <span class="hljs-keyword">is</span> last_line <span class="hljs-keyword">then</span> last_column + <span class="hljs-number">1</span> <span class="hljs-keyword">else</span> codeLine.length
marker = codeLine[...start].replace(<span class="hljs-regexp">/[^\s]/g</span>, <span class="hljs-string">' '</span>) + repeat(<span class="hljs-string">'^'</span>, end - start)</pre></div></div>
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<p>Check to see if were running on a color-enabled TTY.</p>
</div>
<div class="content"><div class='highlight'><pre> <span class="hljs-keyword">if</span> process?
colorsEnabled = process.stdout.isTTY <span class="hljs-keyword">and</span> <span class="hljs-keyword">not</span> process.env.NODE_DISABLE_COLORS
<span class="hljs-keyword">if</span> <span class="hljs-property">@colorful</span> ? colorsEnabled
<span class="hljs-function"><span class="hljs-title">colorize</span> = <span class="hljs-params">(str)</span> -&gt;</span> <span class="hljs-string">"\x1B[1;31m<span class="hljs-subst">#{str}</span>\x1B[0m"</span>
codeLine = codeLine[...start] + colorize(codeLine[start...end]) + codeLine[end..]
marker = colorize marker
<span class="hljs-string">"""
<span class="hljs-subst">#{filename}</span>:<span class="hljs-subst">#{first_line + <span class="hljs-number">1</span>}</span>:<span class="hljs-subst">#{first_column + <span class="hljs-number">1</span>}</span>: error: <span class="hljs-subst">#{<span class="hljs-property">@message</span>}</span>
<span class="hljs-subst">#{codeLine}</span>
<span class="hljs-subst">#{marker}</span>
"""</span>
<span class="hljs-built_in">exports</span>.<span class="hljs-function"><span class="hljs-title">nameWhitespaceCharacter</span> = <span class="hljs-params">(string)</span> -&gt;</span>
<span class="hljs-keyword">switch</span> string
<span class="hljs-keyword">when</span> <span class="hljs-string">' '</span> <span class="hljs-keyword">then</span> <span class="hljs-string">'space'</span>
<span class="hljs-keyword">when</span> <span class="hljs-string">'\n'</span> <span class="hljs-keyword">then</span> <span class="hljs-string">'newline'</span>
<span class="hljs-keyword">when</span> <span class="hljs-string">'\r'</span> <span class="hljs-keyword">then</span> <span class="hljs-string">'carriage return'</span>
<span class="hljs-keyword">when</span> <span class="hljs-string">'\t'</span> <span class="hljs-keyword">then</span> <span class="hljs-string">'tab'</span>
<span class="hljs-keyword">else</span> string</pre></div></div>
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