2138 lines
126 KiB
HTML
2138 lines
126 KiB
HTML
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<!DOCTYPE html>
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<html>
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<head>
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<meta http-equiv="content-type" content="text/html;charset=UTF-8" />
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<title>CoffeeScript</title>
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<link rel="stylesheet" type="text/css" href="documentation/css/docs.css" />
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<link rel="stylesheet" type="text/css" href="documentation/css/idle.css" />
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<link rel="shortcut icon" href="documentation/images/favicon.ico" />
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</head>
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<body class="minimized">
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<div id="fadeout"></div>
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<div id="flybar">
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<a id="logo" href="#top"> </a>
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<div class="navigation toc">
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<div class="button">
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Table of Contents
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</div>
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<div class="contents">
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<a href="#overview">Mini Overview</a>
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<a href="#installation">Installation and Usage</a>
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<a href="#language">Language Reference</a>
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<a href="#whitespace">Significant Whitespace</a>
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<a href="#functions">Functions and Invocation</a>
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<a href="#assignment">Assignment</a>
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<a href="#objects_and_arrays">Objects and Arrays</a>
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<a href="#lexical_scope">Lexical Scoping and Variable Safety</a>
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<a href="#conditionals">Conditionals, Ternaries, and Conditional Assignment</a>
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<a href="#aliases">Aliases</a>
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<a href="#splats">Splats...</a>
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<a href="#while">While Loops</a>
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<a href="#comprehensions">Comprehensions (Arrays, Objects, and Ranges)</a>
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<a href="#slice_splice">Array Slicing and Splicing with Ranges</a>
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<a href="#expressions">Everything is an Expression</a>
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<a href="#existence">The Existential Operator</a>
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<a href="#classes">Classes, Inheritance, and Super</a>
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<a href="#pattern_matching">Pattern Matching</a>
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<a href="#fat_arrow">Function Binding</a>
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<a href="#embedded">Embedded JavaScript</a>
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<a href="#switch">Switch/When/Else</a>
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<a href="#try">Try/Catch/Finally</a>
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<a href="#comparisons">Chained Comparisons</a>
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<a href="#interpolation">String and RegExp Interpolation</a>
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<a href="#strings">Multiline Strings and Heredocs</a>
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<a href="#cake">Cake, and Cakefiles</a>
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<a href="#scripts">"text/coffeescript" Script Tags</a>
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<a href="#resources">Resources</a>
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<a href="#webchat">Web Chat (IRC)</a>
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<a href="#change_log">Change Log</a>
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</div>
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</div>
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<div class="navigation try">
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<div class="button">
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Try CoffeeScript
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</div>
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<div class="contents repl_wrapper">
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<div class="code">
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<div id="repl_source_wrap"><textarea id="repl_source">reverse: (string) ->
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string.split('').reverse().join ''
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alert reverse '.eeffoC yrT'</textarea></div>
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<pre id="repl_results"></pre>
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<button class="full_screen">go full screen</button>
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<button class="minimize">minimize</button>
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<button class="run">run</button>
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<br class="clear" />
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</div>
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</div>
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</div>
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<div class="navigation annotated">
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<div class="button">
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Annotated Source
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</div>
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<div class="contents">
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<a href="documentation/docs/grammar.html">Grammar Rules — src/grammar</a>
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<a href="documentation/docs/lexer.html">Lexing Tokens — src/lexer</a>
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<a href="documentation/docs/rewriter.html">The Rewriter — src/rewriter</a>
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<a href="documentation/docs/nodes.html">The Syntax Tree — src/nodes</a>
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<a href="documentation/docs/scope.html">Lexical Scope — src/scope</a>
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<a href="documentation/docs/helpers.html">Helpers & Utility Functions — src/helpers</a>
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<a href="documentation/docs/coffee-script.html">The CoffeeScript Module — src/coffee-script</a>
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<a href="documentation/docs/cake.html">Cake & Cakefiles — src/cake</a>
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<a href="documentation/docs/command.html">"coffee" Command-Line Utility — src/command</a>
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<a href="documentation/docs/optparse.html">Option Parsing — src/optparse</a>
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<a href="documentation/docs/repl.html">Interactive REPL — src/repl</a>
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</div>
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</div>
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<div id="error" style="display:none;"></div>
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</div>
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<div class="container">
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<span class="bookmark" id="top"></span>
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<p>
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CoffeeScript is a little language that compiles into JavaScript. Think
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of it as JavaScript's less ostentatious kid brother — the same genes,
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roughly the same height, but a different sense of style. Apart from a handful of
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bonus goodies, statements in CoffeeScript correspond one-to-one with their
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equivalent in JavaScript, it's just another way of saying it.
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</p>
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<p>
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<b>Disclaimer:</b>
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CoffeeScript is just for fun. Until it reaches 1.0, <i>there are no guarantees
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that the syntax won't change between versions.</i> That said,
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it compiles into clean JavaScript (the good parts) that can use existing
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JavaScript libraries seamlessly, and passes through
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<a href="http://www.jslint.com/">JSLint</a> without warnings. The compiled
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output is quite readable — pretty-printed, with comments
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preserved intact.
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</p>
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<p>
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<b>Latest Version:</b>
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<a href="http://github.com/jashkenas/coffee-script/tarball/0.6.0">0.6.0</a>
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</p>
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<h2>
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<span id="overview" class="bookmark"></span>
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Mini Overview
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</h2>
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<p><i>CoffeeScript on the left, compiled JavaScript output on the right.</i></p>
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<div class='code'><pre class="idle"><span class="Comment"><span class="Comment">#</span> Assignment:</span>
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number<span class="Keyword">:</span> <span class="Number">42</span>
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opposite_day<span class="Keyword">:</span> <span class="BuiltInConstant">true</span>
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<span class="Comment"><span class="Comment">#</span> Conditions:</span>
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number<span class="Keyword">:</span> <span class="Keyword">-</span><span class="Number">42</span> <span class="Keyword">if</span> opposite_day
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<span class="Comment"><span class="Comment">#</span> Functions:</span>
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<span class="FunctionName">square</span><span class="Keyword">:</span> <span class="FunctionArgument">(</span><span class="FunctionArgument">x</span><span class="FunctionArgument">)</span> <span class="Storage">-></span> x <span class="Keyword">*</span> x
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<span class="Comment"><span class="Comment">#</span> Arrays:</span>
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list<span class="Keyword">:</span> [<span class="Number">1</span>, <span class="Number">2</span>, <span class="Number">3</span>, <span class="Number">4</span>, <span class="Number">5</span>]
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<span class="Comment"><span class="Comment">#</span> Objects:</span>
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math<span class="Keyword">:</span> {
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root<span class="Keyword">:</span> Math.sqrt
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square<span class="Keyword">:</span> square
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<span class="FunctionName">cube</span><span class="Keyword">:</span> <span class="FunctionArgument">(</span><span class="FunctionArgument">x</span><span class="FunctionArgument">)</span> <span class="Storage">-></span> x <span class="Keyword">*</span> square x
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}
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<span class="Comment"><span class="Comment">#</span> Splats:</span>
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<span class="FunctionName">race</span><span class="Keyword">:</span> <span class="FunctionArgument">(</span><span class="FunctionArgument">winner, runners...</span><span class="FunctionArgument">)</span> <span class="Storage">-></span>
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print winner, runners
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<span class="Comment"><span class="Comment">#</span> Existence:</span>
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alert <span class="String"><span class="String">"</span>I knew it!<span class="String">"</span></span> <span class="Keyword">if</span> elvis<span class="Keyword">?</span>
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<span class="Comment"><span class="Comment">#</span> Array comprehensions:</span>
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cubed_list<span class="Keyword">:</span> math.cube num <span class="Keyword">for</span> num <span class="Keyword">in</span> list
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</pre><pre class="idle"><span class="Storage">var</span> _a, _b, _c, _d, cubed_list, list, math, num, number, opposite_day, race, square;
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<span class="Storage">var</span> __slice <span class="Keyword">=</span> <span class="LibraryClassType">Array</span>.<span class="LibraryConstant">prototype</span>.slice;
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<span class="Comment"><span class="Comment">//</span> Assignment:</span>
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number <span class="Keyword">=</span> <span class="Number">42</span>;
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opposite_day <span class="Keyword">=</span> <span class="BuiltInConstant">true</span>;
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<span class="Comment"><span class="Comment">//</span> Conditions:</span>
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<span class="Keyword">if</span> (opposite_day) {
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number <span class="Keyword">=</span> <span class="Keyword">-</span><span class="Number">42</span>;
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}
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<span class="Comment"><span class="Comment">//</span> Functions:</span>
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square <span class="Keyword">=</span> <span class="Storage">function</span> <span class="FunctionName">square</span>(<span class="FunctionArgument">x</span>) {
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<span class="Keyword">return</span> x <span class="Keyword">*</span> x;
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};
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<span class="Comment"><span class="Comment">//</span> Arrays:</span>
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list <span class="Keyword">=</span> [<span class="Number">1</span>, <span class="Number">2</span>, <span class="Number">3</span>, <span class="Number">4</span>, <span class="Number">5</span>];
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<span class="Comment"><span class="Comment">//</span> Objects:</span>
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math <span class="Keyword">=</span> {
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root: <span class="LibraryClassType">Math</span>.sqrt,
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square: square,
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cube: <span class="Storage">function</span> <span class="FunctionName">cube</span>(<span class="FunctionArgument">x</span>) {
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<span class="Keyword">return</span> x <span class="Keyword">*</span> square(x);
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}
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};
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<span class="Comment"><span class="Comment">//</span> Splats:</span>
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race <span class="Keyword">=</span> <span class="Storage">function</span> <span class="FunctionName">race</span>(<span class="FunctionArgument">winner</span>) {
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<span class="Storage">var</span> runners;
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runners <span class="Keyword">=</span> __slice.<span class="LibraryFunction">call</span>(arguments, <span class="Number">1</span>, arguments.<span class="LibraryConstant">length</span> <span class="Keyword">-</span> <span class="Number">0</span>);
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<span class="Keyword">return</span> <span class="LibraryFunction">print</span>(winner, runners);
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};
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<span class="Comment"><span class="Comment">//</span> Existence:</span>
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<span class="Keyword">if</span> ((<span class="Keyword">typeof</span> elvis <span class="Keyword">!</span><span class="Keyword">==</span> <span class="String"><span class="String">"</span>undefined<span class="String">"</span></span> <span class="Keyword">&</span><span class="Keyword">&</span> elvis <span class="Keyword">!</span><span class="Keyword">==</span> <span class="BuiltInConstant">null</span>)) {
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<span class="LibraryFunction">alert</span>(<span class="String"><span class="String">"</span>I knew it!<span class="String">"</span></span>);
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}
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<span class="Comment"><span class="Comment">//</span> Array comprehensions:</span>
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cubed_list <span class="Keyword">=</span> (<span class="Storage">function</span>() {
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_a <span class="Keyword">=</span> []; _c <span class="Keyword">=</span> list;
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<span class="Keyword">for</span> (_b <span class="Keyword">=</span> <span class="Number">0</span>, _d <span class="Keyword">=</span> _c.<span class="LibraryConstant">length</span>; _b <span class="Keyword"><</span> _d; _b<span class="Keyword">++</span>) {
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num <span class="Keyword">=</span> _c[_b];
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_a.<span class="LibraryFunction">push</span>(math.cube(num));
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}
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<span class="Keyword">return</span> _a;
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}).<span class="LibraryFunction">call</span>(<span class="Variable">this</span>);
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</pre><button onclick='javascript: var _a, _b, _c, _d, cubed_list, list, math, num, number, opposite_day, race, square;
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var __slice = Array.prototype.slice;
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// Assignment:
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number = 42;
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opposite_day = true;
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// Conditions:
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if (opposite_day) {
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number = -42;
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}
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// Functions:
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square = function square(x) {
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return x * x;
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};
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// Arrays:
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list = [1, 2, 3, 4, 5];
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// Objects:
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math = {
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root: Math.sqrt,
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square: square,
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cube: function cube(x) {
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return x * square(x);
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}
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};
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// Splats:
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race = function race(winner) {
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var runners;
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runners = __slice.call(arguments, 1, arguments.length - 0);
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return print(winner, runners);
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};
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// Existence:
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if ((typeof elvis !== "undefined" && elvis !== null)) {
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alert("I knew it!");
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}
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// Array comprehensions:
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cubed_list = (function() {
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_a = []; _c = list;
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for (_b = 0, _d = _c.length; _b < _d; _b++) {
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num = _c[_b];
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_a.push(math.cube(num));
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}
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return _a;
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}).call(this);
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;alert(cubed_list);'>run: cubed_list</button><br class='clear' /></div>
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<p>
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For a longer CoffeeScript example, check out
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<a href="documentation/docs/underscore.html">Underscore.coffee</a>, a port
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of the <a href="http://documentcloud.github.com/underscore/">Underscore.js</a>
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library of helper functions. Underscore.coffee can pass the entire Underscore.js
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test suite. The CoffeeScript version is faster than the original for a number
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of methods (in general, due to the speed of CoffeeScript's array comprehensions), and
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after being minified and gzipped, is only 241 bytes larger than the original
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JavaScript version.
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Additional examples are included in the source repository, inside the
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<a href="http://github.com/jashkenas/coffee-script/tree/master/examples/">examples</a> folder.
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</p>
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<h2>
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<span id="installation" class="bookmark"></span>
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Installation and Usage
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</h2>
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<p>
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The CoffeeScript compiler is written in pure CoffeeScript, using a
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<a href="documentation/docs/grammar.html">small DSL</a>
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on top of the <a href="http://github.com/zaach/jison">Jison parser generator</a>, and is available
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as a <a href="http://nodejs.org/">Node.js</a> utility. The core compiler however,
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does not depend on Node, and can be run in other server-side-JavaScript environments,
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or in the browser (see "Try CoffeeScript", above). This may be helpful,
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as Node only run on flavors of nix, and not Windows, for the time being.
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</p>
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<p>
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To install, first make sure you have a working copy of the latest tagged version of
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<a href="http://nodejs.org/">Node.js</a>, currently <b>0.1.33</b> or higher.
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Then clone the CoffeeScript
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<a href="http://github.com/jashkenas/coffee-script">source repository</a>
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from GitHub, or download the latest
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release: <a href="http://github.com/jashkenas/coffee-script/tarball/0.6.0">0.6.0</a>.
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To install the CoffeeScript compiler system-wide
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under <tt>/usr/local</tt>, open the directory and run:
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</p>
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<pre>
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sudo bin/cake install</pre>
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<p>
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This provides the <tt>coffee</tt> command, which will execute CoffeeScripts
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under Node.js by default, but is also used to compile CoffeeScript
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<tt>.coffee</tt> files into JavaScript, or to run an an interactive REPL.
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When compiling to JavaScript, <tt>coffee</tt> writes the output
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as <tt>.js</tt> files in the same directory by default, but output
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can be customized with the following options:
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</p>
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<table>
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<tr>
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<td><code>-c, --compile</code></td>
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<td>
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Compile a <tt>.coffee</tt> script into a <tt>.js</tt> JavaScript file
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of the same name.
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</td>
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</tr>
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<tr>
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<td width="25%"><code>-i, --interactive</code></td>
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<td>
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Launch an interactive CoffeeScript session to try short snippets.
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More pleasant if wrapped with
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<a href="http://utopia.knoware.nl/~hlub/uck/rlwrap/rlwrap.html">rlwrap</a>.
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</td>
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</tr>
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<tr>
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<td><code>-o, --output [DIR]</code></td>
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<td>
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Write out all compiled JavaScript files into the specified directory.
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Use in conjunction with <tt>--compile</tt> or <tt>--watch</tt>.
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</td>
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</tr>
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<tr>
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<td><code>-w, --watch</code></td>
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<td>
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Watch the modification times of the coffee-scripts, recompiling as
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soon as a change occurs.
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</td>
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</tr>
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<tr>
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<td><code>-p, --print</code></td>
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<td>
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Instead of writing out the JavaScript as a file, print it
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directly to <b>stdout</b>.
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</td>
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</tr>
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<tr>
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<td><code>-l, --lint</code></td>
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<td>
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If the <tt>jsl</tt>
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(<a href="http://www.javascriptlint.com/">JavaScript Lint</a>)
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command is installed, use it
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to check the compilation of a CoffeeScript file. (Handy in
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conjunction with <tt>--watch</tt>)
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</td>
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</tr>
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<tr>
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<td><code>-s, --stdio</code></td>
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<td>
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Pipe in CoffeeScript to STDIN and get back JavaScript over STDOUT.
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Good for use with processes written in other languages. An example:<br />
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<tt>cat src/cake.coffee | coffee -sc</tt>
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</td>
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</tr>
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<tr>
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<td><code>-e, --eval</code></td>
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<td>
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Compile and print a little snippet of CoffeeScript directly from the
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command line. For example:<br /><tt>coffee -e "puts num for num in [10..1]"</tt>
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</td>
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</tr>
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<tr>
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<td><code>--no-wrap</code></td>
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<td>
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Compile the JavaScript without the top-level function safety wrapper.
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(Used for CoffeeScript as a Node.js module.)
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</td>
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</tr>
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<tr>
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<td><code>-t, --tokens</code></td>
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<td>
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Instead of parsing the CoffeeScript, just lex it, and print out the
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token stream: <tt>[IDENTIFIER square] [ASSIGN :] [PARAM_START (]</tt> ...
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</td>
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</tr>
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<tr>
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<td><code>-n, --nodes</code></td>
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<td>
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Instead of compiling the CoffeeScript, just lex and parse it, and print
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out the parse tree:
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<pre class="no_bar">
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Expressions
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Assign
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Value "square"
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Code "x"
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Op *
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Value "x"
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Value "x"</pre>
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</td>
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</tr>
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</table>
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<p>
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<b>Examples:</b>
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</p>
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<pre>
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coffee -c path/to/script.coffee
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coffee --interactive
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coffee --watch --lint experimental.coffee
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coffee --print app/scripts/*.coffee > concatenation.js</pre>
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<h2>
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<span id="language" class="bookmark"></span>
|
|
Language Reference
|
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</h2>
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<p>
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<i>
|
|
This reference is structured so that it can be read from top to bottom,
|
|
if you like. Later sections use ideas and syntax previously introduced.
|
|
Familiarity with JavaScript is assumed.
|
|
In all of the following examples, the source CoffeeScript is provided on
|
|
the left, and the direct compilation into JavaScript is on the right.
|
|
</i>
|
|
</p>
|
|
|
|
<p>
|
|
<i>
|
|
Many of the examples can be run (where it makes sense) by pressing the "run"
|
|
button towards the bottom right. You can also paste examples into
|
|
"Try CoffeeScript" in the toolbar, and play with them from there.
|
|
</i>
|
|
<p>
|
|
<span id="whitespace" class="bookmark"></span>
|
|
<b class="header">Significant Whitespace</b>
|
|
CoffeeScript uses Python-style significant whitespace: You don't need to
|
|
use semicolons <tt>;</tt> to terminate expressions, ending
|
|
the line will do just as well. Semicolons can still be used to fit
|
|
multiple expressions onto a single line. Instead of using curly braces
|
|
<tt>{ }</tt> to delimit blocks of code (like <a href="#functions">functions</a>,
|
|
<a href="#conditionals">if-statements</a>,
|
|
<a href="#switch">switch</a>, and <a href="#try">try/catch</a>),
|
|
use indentation.
|
|
</p>
|
|
|
|
<p>
|
|
You don't need to use parentheses to invoke a function if you're passing
|
|
arguments:<br /><tt>print "coffee"</tt>
|
|
</p>
|
|
|
|
<p>
|
|
You can use newlines to break up your expression into smaller pieces,
|
|
as long as CoffeeScript can determine that the line hasn't finished yet,
|
|
because it ends with an operator or a dot.
|
|
</p>
|
|
|
|
<p>
|
|
<span id="functions" class="bookmark"></span>
|
|
<b class="header">Functions and Invocation</b>
|
|
Functions are defined by a list of parameters, an arrow, and the
|
|
function body. The empty function looks like this: <tt>-></tt> All
|
|
functions in CoffeeScript are named by default, for easier debugging.
|
|
</p>
|
|
<div class='code'><pre class="idle"><span class="FunctionName">square</span><span class="Keyword">:</span> <span class="FunctionArgument">(</span><span class="FunctionArgument">x</span><span class="FunctionArgument">)</span> <span class="Storage">-></span> x <span class="Keyword">*</span> x
|
|
<span class="FunctionName">cube</span><span class="Keyword">:</span> <span class="FunctionArgument">(</span><span class="FunctionArgument">x</span><span class="FunctionArgument">)</span> <span class="Storage">-></span> square(x) <span class="Keyword">*</span> x
|
|
</pre><pre class="idle"><span class="Storage">var</span> cube, square;
|
|
square <span class="Keyword">=</span> <span class="Storage">function</span> <span class="FunctionName">square</span>(<span class="FunctionArgument">x</span>) {
|
|
<span class="Keyword">return</span> x <span class="Keyword">*</span> x;
|
|
};
|
|
cube <span class="Keyword">=</span> <span class="Storage">function</span> <span class="FunctionName">cube</span>(<span class="FunctionArgument">x</span>) {
|
|
<span class="Keyword">return</span> square(x) <span class="Keyword">*</span> x;
|
|
};
|
|
</pre><button onclick='javascript: var cube, square;
|
|
square = function square(x) {
|
|
return x * x;
|
|
};
|
|
cube = function cube(x) {
|
|
return square(x) * x;
|
|
};
|
|
;alert(cube(5));'>run: cube(5)</button><br class='clear' /></div>
|
|
<p>
|
|
If you'd like to assign a function literal to a variable, but not have
|
|
it be named, just wrap the function definition in parentheses:
|
|
<tt>((x) -> x * x)</tt>
|
|
</p>
|
|
|
|
<p>
|
|
<span id="assignment" class="bookmark"></span>
|
|
<b class="header">Assignment</b>
|
|
Use a colon <tt>:</tt> to assign, as in
|
|
<a href="http://json.org">JSON</a>. Equal signs are only needed for
|
|
mathy things. While colons are preferred, the two may be used interchangeably,
|
|
even within object literals.
|
|
</p>
|
|
<div class='code'><pre class="idle">greeting<span class="Keyword">:</span> <span class="String"><span class="String">"</span>Hello CoffeeScript<span class="String">"</span></span>
|
|
difficulty<span class="Keyword">:</span> <span class="Number">0.5</span>
|
|
</pre><pre class="idle"><span class="Storage">var</span> difficulty, greeting;
|
|
greeting <span class="Keyword">=</span> <span class="String"><span class="String">"</span>Hello CoffeeScript<span class="String">"</span></span>;
|
|
difficulty <span class="Keyword">=</span> <span class="Number">0.5</span>;
|
|
</pre><button onclick='javascript: var difficulty, greeting;
|
|
greeting = "Hello CoffeeScript";
|
|
difficulty = 0.5;
|
|
;alert(greeting);'>run: greeting</button><br class='clear' /></div>
|
|
<p>
|
|
All declaration of new variables is pushed up to the top of the nearest
|
|
lexical scope, so that assignment may always be performed within expressions.
|
|
</p>
|
|
|
|
<p>
|
|
<span id="objects_and_arrays" class="bookmark"></span>
|
|
<b class="header">Objects and Arrays</b>
|
|
Object and Array literals look very similar to their JavaScript cousins.
|
|
When you spread out each assignment on a separate line, the commas are
|
|
optional. In this way, assigning object properties looks the same as
|
|
assigning local variables, and can be moved around freely. Feel free to mix
|
|
and match the two styles.
|
|
</p>
|
|
<div class='code'><pre class="idle">song<span class="Keyword">:</span> [<span class="String"><span class="String">"</span>do<span class="String">"</span></span>, <span class="String"><span class="String">"</span>re<span class="String">"</span></span>, <span class="String"><span class="String">"</span>mi<span class="String">"</span></span>, <span class="String"><span class="String">"</span>fa<span class="String">"</span></span>, <span class="String"><span class="String">"</span>so<span class="String">"</span></span>]
|
|
|
|
ages<span class="Keyword">:</span> {
|
|
max<span class="Keyword">:</span> <span class="Number">10</span>
|
|
ida<span class="Keyword">:</span> <span class="Number">9</span>
|
|
tim<span class="Keyword">:</span> <span class="Number">11</span>
|
|
}
|
|
|
|
matrix<span class="Keyword">:</span> [
|
|
<span class="Number">1</span>, <span class="Number">0</span>, <span class="Number">1</span>
|
|
<span class="Number">0</span>, <span class="Number">0</span>, <span class="Number">1</span>
|
|
<span class="Number">1</span>, <span class="Number">1</span>, <span class="Number">0</span>
|
|
]
|
|
</pre><pre class="idle"><span class="Storage">var</span> ages, matrix, song;
|
|
song <span class="Keyword">=</span> [<span class="String"><span class="String">"</span>do<span class="String">"</span></span>, <span class="String"><span class="String">"</span>re<span class="String">"</span></span>, <span class="String"><span class="String">"</span>mi<span class="String">"</span></span>, <span class="String"><span class="String">"</span>fa<span class="String">"</span></span>, <span class="String"><span class="String">"</span>so<span class="String">"</span></span>];
|
|
ages <span class="Keyword">=</span> {
|
|
max: <span class="Number">10</span>,
|
|
ida: <span class="Number">9</span>,
|
|
tim: <span class="Number">11</span>
|
|
};
|
|
matrix <span class="Keyword">=</span> [<span class="Number">1</span>, <span class="Number">0</span>, <span class="Number">1</span>, <span class="Number">0</span>, <span class="Number">0</span>, <span class="Number">1</span>, <span class="Number">1</span>, <span class="Number">1</span>, <span class="Number">0</span>];
|
|
</pre><button onclick='javascript: var ages, matrix, song;
|
|
song = ["do", "re", "mi", "fa", "so"];
|
|
ages = {
|
|
max: 10,
|
|
ida: 9,
|
|
tim: 11
|
|
};
|
|
matrix = [1, 0, 1, 0, 0, 1, 1, 1, 0];
|
|
;alert(song.join(","));'>run: song.join(",")</button><br class='clear' /></div>
|
|
|
|
<p>
|
|
<span id="lexical_scope" class="bookmark"></span>
|
|
<b class="header">Lexical Scoping and Variable Safety</b>
|
|
The CoffeeScript compiler takes care to make sure that all of your variables
|
|
are properly declared within lexical scope — you never need to write
|
|
<tt>var</tt> yourself.
|
|
</p>
|
|
<div class='code'><pre class="idle">num<span class="Keyword">:</span> <span class="Number">1</span>
|
|
<span class="FunctionName">change_numbers</span><span class="Keyword">:</span> <span class="Storage">-></span>
|
|
new_num<span class="Keyword">:</span> <span class="Keyword">-</span><span class="Number">1</span>
|
|
num<span class="Keyword">:</span> <span class="Number">10</span>
|
|
new_num<span class="Keyword">:</span> change_numbers()
|
|
</pre><pre class="idle"><span class="Storage">var</span> change_numbers, new_num, num;
|
|
num <span class="Keyword">=</span> <span class="Number">1</span>;
|
|
change_numbers <span class="Keyword">=</span> <span class="Storage">function</span> <span class="FunctionName">change_numbers</span>() {
|
|
<span class="Storage">var</span> new_num;
|
|
new_num <span class="Keyword">=</span> <span class="Keyword">-</span><span class="Number">1</span>;
|
|
num <span class="Keyword">=</span> <span class="Number">10</span>;
|
|
<span class="Keyword">return</span> num;
|
|
};
|
|
new_num <span class="Keyword">=</span> change_numbers();
|
|
</pre><button onclick='javascript: var change_numbers, new_num, num;
|
|
num = 1;
|
|
change_numbers = function change_numbers() {
|
|
var new_num;
|
|
new_num = -1;
|
|
num = 10;
|
|
return num;
|
|
};
|
|
new_num = change_numbers();
|
|
;alert(new_num);'>run: new_num</button><br class='clear' /></div>
|
|
<p>
|
|
Notice how the all of the variable declarations have been pushed up to
|
|
the top of the closest scope, the first time they appear.
|
|
<b>num</b> is not redeclared within the inner function, because it's
|
|
already in scope; the <b>new_num</b> within the function, on the other hand,
|
|
should not be able to change the value of the external variable of the same name, and
|
|
therefore has a declaration of its own.
|
|
</p>
|
|
<p>
|
|
This behavior is effectively identical to Ruby's scope for local variables.
|
|
Because you don't have direct access to the <tt>var</tt> keyword,
|
|
it's impossible to shadow an outer variable on purpose, you may only refer
|
|
to it. So be careful that you're not reusing the name of an external
|
|
variable accidentally, if you're writing a deeply nested function.
|
|
</p>
|
|
<p>
|
|
Although suppressed within this documentation for clarity, all
|
|
CoffeeScript output is wrapped in an anonymous function:
|
|
<tt>(function(){ ... })();</tt> This safety wrapper, combined with the
|
|
automatic generation of the <tt>var</tt> keyword, make it exceedingly difficult
|
|
to pollute the global namespace by accident.
|
|
</p>
|
|
<p>
|
|
If you'd like to create top-level variables for other scripts to use,
|
|
attach them as properties on <b>window</b>, or on the <b>exports</b>
|
|
object in CommonJS. The <b>existential operator</b> (below), gives you a
|
|
reliable way to figure out where to add them, if you're targeting both
|
|
CommonJS and the browser: <tt>root: exports ? this</tt>
|
|
</p>
|
|
|
|
<p>
|
|
<span id="conditionals" class="bookmark"></span>
|
|
<b class="header">Conditionals, Ternaries, and Conditional Assignment</b>
|
|
<b>If/else</b> statements can be written without the use of parentheses and
|
|
curly brackets. As with functions and other block expressions,
|
|
multi-line conditionals are delimited by indentation. There's also a handy
|
|
postfix form, with the <tt>if</tt> or <tt>unless</tt> at the end.
|
|
</p>
|
|
<p>
|
|
CoffeeScript will compile <b>if</b> statements using the ternary operator
|
|
when possible, to make it easier to use the result as an expression.
|
|
</p>
|
|
<div class='code'><pre class="idle">mood<span class="Keyword">:</span> greatly_improved <span class="Keyword">if</span> singing
|
|
|
|
<span class="Keyword">if</span> happy <span class="Keyword">and</span> knows_it
|
|
claps_hands()
|
|
cha_cha_cha()
|
|
|
|
date<span class="Keyword">:</span> <span class="Keyword">if</span> friday <span class="Keyword">then</span> sue <span class="Keyword">else</span> jill
|
|
|
|
expensive<span class="Keyword">:</span> <span class="Keyword">or</span> do_the_math()
|
|
</pre><pre class="idle"><span class="Storage">var</span> date, expensive, mood;
|
|
<span class="Keyword">if</span> (singing) {
|
|
mood <span class="Keyword">=</span> greatly_improved;
|
|
}
|
|
<span class="Keyword">if</span> (happy <span class="Keyword">&</span><span class="Keyword">&</span> knows_it) {
|
|
claps_hands();
|
|
cha_cha_cha();
|
|
}
|
|
date <span class="Keyword">=</span> friday ? sue : jill;
|
|
expensive <span class="Keyword">=</span> expensive <span class="Keyword">||</span> do_the_math();
|
|
</pre><br class='clear' /></div>
|
|
<p>
|
|
You can assign a variable to a half-expression to perform an operation
|
|
like Ruby's <tt>||=</tt>, which only assigns a value to a variable
|
|
if the variable's current value is falsy.
|
|
</p>
|
|
|
|
<p>
|
|
<span id="aliases" class="bookmark"></span>
|
|
<b class="header">Aliases</b>
|
|
Because the <tt>==</tt> operator frequently causes undesirable coercion,
|
|
is intransitive, and has a different meaning than in other languages,
|
|
CoffeeScript compiles <tt>==</tt> into <tt>===</tt>, and <tt>!=</tt> into
|
|
<tt>!==</tt>.
|
|
In addition, <tt>is</tt> compiles into <tt>===</tt>,
|
|
and <tt>isnt</tt> into <tt>!==</tt>.
|
|
</p>
|
|
<p>
|
|
You can use <tt>not</tt> as an alias for <tt>!</tt>.
|
|
</p>
|
|
<p>
|
|
For logic, <tt>and</tt> compiles to <tt>&&</tt>, and <tt>or</tt>
|
|
into <tt>||</tt>.
|
|
</p>
|
|
<p>
|
|
Instead of a newline or semicolon, <tt>then</tt> can be used to separate
|
|
conditions from expressions, in <b>while</b>,
|
|
<b>if</b>/<b>else</b>, and <b>switch</b>/<b>when</b> statements.
|
|
</p>
|
|
<p>
|
|
As in <a href="http://yaml.org/">YAML</a>, <tt>on</tt> and <tt>yes</tt>
|
|
are the same as boolean <tt>true</tt>, while <tt>off</tt> and <tt>no</tt> are boolean <tt>false</tt>.
|
|
</p>
|
|
<p>
|
|
For single-line statements, <tt>unless</tt> can be used as the inverse of <tt>if</tt>.
|
|
</p>
|
|
<p>
|
|
As a shortcut for <tt>this.property</tt>, you can use <tt>@property</tt>.
|
|
</p>
|
|
<div class='code'><pre class="idle">launch() <span class="Keyword">if</span> ignition <span class="Keyword">is</span> <span class="BuiltInConstant">on</span>
|
|
|
|
volume<span class="Keyword">:</span> <span class="Number">10</span> <span class="Keyword">if</span> band <span class="Keyword">isnt</span> spinal_tap
|
|
|
|
let_the_wild_rumpus_begin() <span class="Keyword">unless</span> answer <span class="Keyword">is</span> <span class="BuiltInConstant">no</span>
|
|
|
|
<span class="Keyword">if</span> car.speed <span class="Keyword"><</span> speed_limit <span class="Keyword">then</span> accelerate()
|
|
|
|
print <span class="String"><span class="String">"</span>My name is <span class="String">"</span></span> <span class="Keyword">+</span> <span class="Variable">@name</span>
|
|
</pre><pre class="idle"><span class="Storage">var</span> volume;
|
|
<span class="Keyword">if</span> (ignition <span class="Keyword">===</span> <span class="BuiltInConstant">true</span>) {
|
|
launch();
|
|
}
|
|
<span class="Keyword">if</span> (band <span class="Keyword">!</span><span class="Keyword">==</span> spinal_tap) {
|
|
volume <span class="Keyword">=</span> <span class="Number">10</span>;
|
|
}
|
|
<span class="Keyword">if</span> (<span class="Keyword">!</span>(answer <span class="Keyword">===</span> <span class="BuiltInConstant">false</span>)) {
|
|
let_the_wild_rumpus_begin();
|
|
}
|
|
car.speed <span class="Keyword"><</span> speed_limit ? accelerate() : <span class="BuiltInConstant">null</span>;
|
|
<span class="LibraryFunction">print</span>(<span class="String"><span class="String">"</span>My name is <span class="String">"</span></span> <span class="Keyword">+</span> <span class="Variable">this</span>.<span class="LibraryConstant">name</span>);
|
|
</pre><br class='clear' /></div>
|
|
|
|
<p>
|
|
<span id="splats" class="bookmark"></span>
|
|
<b class="header">Splats...</b>
|
|
The JavaScript <b>arguments object</b> is a useful way to work with
|
|
functions that accept variable numbers of arguments. CoffeeScript provides
|
|
splats <tt>...</tt>, both for function definition as well as invocation,
|
|
making variable numbers of arguments a little bit more palatable.
|
|
</p>
|
|
<div class='code'><pre class="idle">gold<span class="Keyword">:</span> silver<span class="Keyword">:</span> the_field<span class="Keyword">:</span> <span class="String"><span class="String">"</span>unknown<span class="String">"</span></span>
|
|
|
|
<span class="FunctionName">award_medals</span><span class="Keyword">:</span> <span class="FunctionArgument">(</span><span class="FunctionArgument">first, second, rest...</span><span class="FunctionArgument">)</span> <span class="Storage">-></span>
|
|
gold<span class="Keyword">:</span> first
|
|
silver<span class="Keyword">:</span> second
|
|
the_field<span class="Keyword">:</span> rest
|
|
|
|
contenders<span class="Keyword">:</span> [
|
|
<span class="String"><span class="String">"</span>Michael Phelps<span class="String">"</span></span>
|
|
<span class="String"><span class="String">"</span>Liu Xiang<span class="String">"</span></span>
|
|
<span class="String"><span class="String">"</span>Yao Ming<span class="String">"</span></span>
|
|
<span class="String"><span class="String">"</span>Allyson Felix<span class="String">"</span></span>
|
|
<span class="String"><span class="String">"</span>Shawn Johnson<span class="String">"</span></span>
|
|
<span class="String"><span class="String">"</span>Roman Sebrle<span class="String">"</span></span>
|
|
<span class="String"><span class="String">"</span>Guo Jingjing<span class="String">"</span></span>
|
|
<span class="String"><span class="String">"</span>Tyson Gay<span class="String">"</span></span>
|
|
<span class="String"><span class="String">"</span>Asafa Powell<span class="String">"</span></span>
|
|
<span class="String"><span class="String">"</span>Usain Bolt<span class="String">"</span></span>
|
|
]
|
|
|
|
award_medals contenders...
|
|
|
|
alert <span class="String"><span class="String">"</span>Gold: <span class="String">"</span></span> <span class="Keyword">+</span> gold
|
|
alert <span class="String"><span class="String">"</span>Silver: <span class="String">"</span></span> <span class="Keyword">+</span> silver
|
|
alert <span class="String"><span class="String">"</span>The Field: <span class="String">"</span></span> <span class="Keyword">+</span> the_field
|
|
</pre><pre class="idle"><span class="Storage">var</span> award_medals, contenders, gold, silver, the_field;
|
|
<span class="Storage">var</span> __slice <span class="Keyword">=</span> <span class="LibraryClassType">Array</span>.<span class="LibraryConstant">prototype</span>.slice;
|
|
gold <span class="Keyword">=</span> (silver <span class="Keyword">=</span> (the_field <span class="Keyword">=</span> <span class="String"><span class="String">"</span>unknown<span class="String">"</span></span>));
|
|
award_medals <span class="Keyword">=</span> <span class="Storage">function</span> <span class="FunctionName">award_medals</span>(<span class="FunctionArgument">first, second</span>) {
|
|
<span class="Storage">var</span> rest;
|
|
rest <span class="Keyword">=</span> __slice.<span class="LibraryFunction">call</span>(arguments, <span class="Number">2</span>, arguments.<span class="LibraryConstant">length</span> <span class="Keyword">-</span> <span class="Number">0</span>);
|
|
gold <span class="Keyword">=</span> first;
|
|
silver <span class="Keyword">=</span> second;
|
|
the_field <span class="Keyword">=</span> rest;
|
|
<span class="Keyword">return</span> the_field;
|
|
};
|
|
contenders <span class="Keyword">=</span> [<span class="String"><span class="String">"</span>Michael Phelps<span class="String">"</span></span>, <span class="String"><span class="String">"</span>Liu Xiang<span class="String">"</span></span>, <span class="String"><span class="String">"</span>Yao Ming<span class="String">"</span></span>, <span class="String"><span class="String">"</span>Allyson Felix<span class="String">"</span></span>, <span class="String"><span class="String">"</span>Shawn Johnson<span class="String">"</span></span>, <span class="String"><span class="String">"</span>Roman Sebrle<span class="String">"</span></span>, <span class="String"><span class="String">"</span>Guo Jingjing<span class="String">"</span></span>, <span class="String"><span class="String">"</span>Tyson Gay<span class="String">"</span></span>, <span class="String"><span class="String">"</span>Asafa Powell<span class="String">"</span></span>, <span class="String"><span class="String">"</span>Usain Bolt<span class="String">"</span></span>];
|
|
award_medals.<span class="LibraryFunction">apply</span>(<span class="Variable">this</span>, contenders);
|
|
<span class="LibraryFunction">alert</span>(<span class="String"><span class="String">"</span>Gold: <span class="String">"</span></span> <span class="Keyword">+</span> gold);
|
|
<span class="LibraryFunction">alert</span>(<span class="String"><span class="String">"</span>Silver: <span class="String">"</span></span> <span class="Keyword">+</span> silver);
|
|
<span class="LibraryFunction">alert</span>(<span class="String"><span class="String">"</span>The Field: <span class="String">"</span></span> <span class="Keyword">+</span> the_field);
|
|
</pre><button onclick='javascript: var award_medals, contenders, gold, silver, the_field;
|
|
var __slice = Array.prototype.slice;
|
|
gold = (silver = (the_field = "unknown"));
|
|
award_medals = function award_medals(first, second) {
|
|
var rest;
|
|
rest = __slice.call(arguments, 2, arguments.length - 0);
|
|
gold = first;
|
|
silver = second;
|
|
the_field = rest;
|
|
return the_field;
|
|
};
|
|
contenders = ["Michael Phelps", "Liu Xiang", "Yao Ming", "Allyson Felix", "Shawn Johnson", "Roman Sebrle", "Guo Jingjing", "Tyson Gay", "Asafa Powell", "Usain Bolt"];
|
|
award_medals.apply(this, contenders);
|
|
alert("Gold: " + gold);
|
|
alert("Silver: " + silver);
|
|
alert("The Field: " + the_field);
|
|
;'>run</button><br class='clear' /></div>
|
|
|
|
<p>
|
|
<span id="while" class="bookmark"></span>
|
|
<b class="header">While Loops</b>
|
|
The only low-level loop that CoffeeScript provides is the <b>while</b> loop. The
|
|
main difference from JavaScript is that the <b>while</b> loop can be used
|
|
as an expression, returning an array containing the result of each iteration
|
|
through the loop.
|
|
</p>
|
|
<div class='code'><pre class="idle"><span class="Comment"><span class="Comment">#</span> Econ 101</span>
|
|
<span class="Keyword">if</span> <span class="Variable">this</span>.studying_economics
|
|
<span class="Keyword">while</span> supply <span class="Keyword">></span> demand <span class="Keyword">then</span> buy()
|
|
<span class="Keyword">while</span> supply <span class="Keyword"><</span> demand <span class="Keyword">then</span> sell()
|
|
|
|
<span class="Comment"><span class="Comment">#</span> Nursery Rhyme</span>
|
|
num<span class="Keyword">:</span> <span class="Number">6</span>
|
|
lyrics<span class="Keyword">:</span> <span class="Keyword">while</span> num <span class="Keyword">-</span><span class="Keyword">=</span> <span class="Number">1</span>
|
|
num <span class="Keyword">+</span> <span class="String"><span class="String">"</span> little monkeys, jumping on the bed.</span>
|
|
<span class="String"> One fell out and bumped his head.<span class="String">"</span></span>
|
|
</pre><pre class="idle"><span class="Storage">var</span> _a, lyrics, num;
|
|
<span class="Comment"><span class="Comment">//</span> Econ 101</span>
|
|
<span class="Keyword">if</span> (<span class="Variable">this</span>.studying_economics) {
|
|
<span class="Keyword">while</span> (supply <span class="Keyword">></span> demand) {
|
|
buy();
|
|
}
|
|
<span class="Keyword">while</span> (supply <span class="Keyword"><</span> demand) {
|
|
sell();
|
|
}
|
|
}
|
|
<span class="Comment"><span class="Comment">//</span> Nursery Rhyme</span>
|
|
num <span class="Keyword">=</span> <span class="Number">6</span>;
|
|
lyrics <span class="Keyword">=</span> (<span class="Storage">function</span>() {
|
|
_a <span class="Keyword">=</span> [];
|
|
<span class="Keyword">while</span> (num <span class="Keyword">-</span><span class="Keyword">=</span> <span class="Number">1</span>) {
|
|
_a.<span class="LibraryFunction">push</span>(num <span class="Keyword">+</span> <span class="String"><span class="String">"</span> little monkeys, jumping on the bed. \</span>
|
|
<span class="String">One fell out and bumped his head.<span class="String">"</span></span>);
|
|
}
|
|
<span class="Keyword">return</span> _a;
|
|
}).<span class="LibraryFunction">call</span>(<span class="Variable">this</span>);
|
|
</pre><button onclick='javascript: var _a, lyrics, num;
|
|
// Econ 101
|
|
if (this.studying_economics) {
|
|
while (supply > demand) {
|
|
buy();
|
|
}
|
|
while (supply < demand) {
|
|
sell();
|
|
}
|
|
}
|
|
// Nursery Rhyme
|
|
num = 6;
|
|
lyrics = (function() {
|
|
_a = [];
|
|
while (num -= 1) {
|
|
_a.push(num + " little monkeys, jumping on the bed. \
|
|
One fell out and bumped his head.");
|
|
}
|
|
return _a;
|
|
}).call(this);
|
|
;alert(lyrics.join("\n"));'>run: lyrics.join("\n")</button><br class='clear' /></div>
|
|
<p>
|
|
Other JavaScript loops, such as <b>for</b> loops and <b>do-while</b> loops
|
|
can be mimicked by variations on <b>while</b>, but the hope is that you
|
|
won't need to do that with CoffeeScript, either because you're using
|
|
<b>each</b> (<b>forEach</b>) style iterators, or...
|
|
</p>
|
|
|
|
<p>
|
|
<span id="comprehensions" class="bookmark"></span>
|
|
<b class="header">Comprehensions (Arrays, Objects, and Ranges)</b>
|
|
For your looping needs, CoffeeScript provides array comprehensions
|
|
similar to Python's. They replace (and compile into) <b>for</b> loops, with
|
|
optional guard clauses and the value of the current array index.
|
|
Unlike for loops, array comprehensions are expressions, and can be returned
|
|
and assigned. They should be able to handle most places where you otherwise
|
|
would use a loop, <b>each</b>/<b>forEach</b>, <b>map</b>, or <b>select</b>/<b>filter</b>.
|
|
</p>
|
|
<div class='code'><pre class="idle"><span class="Comment"><span class="Comment">#</span> Eat lunch.</span>
|
|
lunch<span class="Keyword">:</span> eat food <span class="Keyword">for</span> food <span class="Keyword">in</span> [<span class="String"><span class="String">'</span>toast<span class="String">'</span></span>, <span class="String"><span class="String">'</span>cheese<span class="String">'</span></span>, <span class="String"><span class="String">'</span>wine<span class="String">'</span></span>]
|
|
|
|
<span class="Comment"><span class="Comment">#</span> Naive collision detection.</span>
|
|
<span class="Keyword">for</span> roid <span class="Keyword">in</span> asteroids
|
|
<span class="Keyword">for</span> roid2 <span class="Keyword">in</span> asteroids <span class="Keyword">when</span> roid <span class="Keyword">isnt</span> roid2
|
|
roid.explode() <span class="Keyword">if</span> roid.overlaps roid2
|
|
</pre><pre class="idle"><span class="Storage">var</span> _a, _b, _c, _d, _e, _f, _g, _h, _i, _j, food, lunch, roid, roid2;
|
|
<span class="Comment"><span class="Comment">//</span> Eat lunch.</span>
|
|
lunch <span class="Keyword">=</span> (<span class="Storage">function</span>() {
|
|
_a <span class="Keyword">=</span> []; _c <span class="Keyword">=</span> [<span class="String"><span class="String">'</span>toast<span class="String">'</span></span>, <span class="String"><span class="String">'</span>cheese<span class="String">'</span></span>, <span class="String"><span class="String">'</span>wine<span class="String">'</span></span>];
|
|
<span class="Keyword">for</span> (_b <span class="Keyword">=</span> <span class="Number">0</span>, _d <span class="Keyword">=</span> _c.<span class="LibraryConstant">length</span>; _b <span class="Keyword"><</span> _d; _b<span class="Keyword">++</span>) {
|
|
food <span class="Keyword">=</span> _c[_b];
|
|
_a.<span class="LibraryFunction">push</span>(eat(food));
|
|
}
|
|
<span class="Keyword">return</span> _a;
|
|
}).<span class="LibraryFunction">call</span>(<span class="Variable">this</span>);
|
|
<span class="Comment"><span class="Comment">//</span> Naive collision detection.</span>
|
|
_f <span class="Keyword">=</span> asteroids;
|
|
<span class="Keyword">for</span> (_e <span class="Keyword">=</span> <span class="Number">0</span>, _g <span class="Keyword">=</span> _f.<span class="LibraryConstant">length</span>; _e <span class="Keyword"><</span> _g; _e<span class="Keyword">++</span>) {
|
|
roid <span class="Keyword">=</span> _f[_e];
|
|
_i <span class="Keyword">=</span> asteroids;
|
|
<span class="Keyword">for</span> (_h <span class="Keyword">=</span> <span class="Number">0</span>, _j <span class="Keyword">=</span> _i.<span class="LibraryConstant">length</span>; _h <span class="Keyword"><</span> _j; _h<span class="Keyword">++</span>) {
|
|
roid2 <span class="Keyword">=</span> _i[_h];
|
|
<span class="Keyword">if</span> (roid <span class="Keyword">!</span><span class="Keyword">==</span> roid2) {
|
|
<span class="Keyword">if</span> (roid.overlaps(roid2)) {
|
|
roid.explode();
|
|
}
|
|
}
|
|
}
|
|
}
|
|
</pre><br class='clear' /></div>
|
|
<p>
|
|
If you know the start and end of your loop, or would like to step through
|
|
in fixed-size increments, you can use a range to specify the start and
|
|
end of your comprehension. (The long line-breaking "for" definitions in
|
|
the compiled JS below allow ranges to count downwards, as well as upwards).
|
|
</p>
|
|
<div class='code'><pre class="idle">countdown<span class="Keyword">:</span> num <span class="Keyword">for</span> num <span class="Keyword">in</span> [<span class="Number">10</span>..<span class="Number">1</span>]
|
|
|
|
<span class="FunctionName">egg_delivery</span><span class="Keyword">:</span> <span class="Storage">-></span>
|
|
<span class="Keyword">for</span> i <span class="Keyword">in</span> [<span class="Number">0</span>...eggs.length] <span class="Keyword">by</span> <span class="Number">12</span>
|
|
dozen_eggs<span class="Keyword">:</span> eggs[i...i<span class="Keyword">+</span><span class="Number">12</span>]
|
|
deliver <span class="Keyword">new</span> <span class="TypeName">egg_carton</span>(dozen)
|
|
</pre><pre class="idle"><span class="Storage">var</span> _a, _b, _c, _d, countdown, egg_delivery, num;
|
|
countdown <span class="Keyword">=</span> (<span class="Storage">function</span>() {
|
|
_a <span class="Keyword">=</span> []; _c <span class="Keyword">=</span> <span class="Number">10</span>; _d <span class="Keyword">=</span> <span class="Number">1</span>;
|
|
<span class="Keyword">for</span> (_b <span class="Keyword">=</span> <span class="Number">0</span>, num <span class="Keyword">=</span> _c; (_c <span class="Keyword"><=</span> _d ? num <span class="Keyword"><=</span> _d : num <span class="Keyword">>=</span> _d); (_c <span class="Keyword"><=</span> _d ? num <span class="Keyword">+</span><span class="Keyword">=</span> <span class="Number">1</span> : num <span class="Keyword">-</span><span class="Keyword">=</span> <span class="Number">1</span>), _b<span class="Keyword">++</span>) {
|
|
_a.<span class="LibraryFunction">push</span>(num);
|
|
}
|
|
<span class="Keyword">return</span> _a;
|
|
}).<span class="LibraryFunction">call</span>(<span class="Variable">this</span>);
|
|
egg_delivery <span class="Keyword">=</span> <span class="Storage">function</span> <span class="FunctionName">egg_delivery</span>() {
|
|
<span class="Storage">var</span> _e, _f, _g, _h, dozen_eggs, i;
|
|
_e <span class="Keyword">=</span> []; _g <span class="Keyword">=</span> <span class="Number">0</span>; _h <span class="Keyword">=</span> eggs.<span class="LibraryConstant">length</span>;
|
|
<span class="Keyword">for</span> (_f <span class="Keyword">=</span> <span class="Number">0</span>, i <span class="Keyword">=</span> _g; (_g <span class="Keyword"><=</span> _h ? i <span class="Keyword"><</span> _h : i <span class="Keyword">></span> _h); (_g <span class="Keyword"><=</span> _h ? i <span class="Keyword">+</span><span class="Keyword">=</span> <span class="Number">12</span> : i <span class="Keyword">-</span><span class="Keyword">=</span> <span class="Number">12</span>), _f<span class="Keyword">++</span>) {
|
|
_e.<span class="LibraryFunction">push</span>((<span class="Storage">function</span>() {
|
|
dozen_eggs <span class="Keyword">=</span> eggs.<span class="LibraryFunction">slice</span>(i, i <span class="Keyword">+</span> <span class="Number">12</span>);
|
|
<span class="Keyword">return</span> deliver(<span class="Keyword">new</span> <span class="TypeName">egg_carton</span>(dozen));
|
|
}).<span class="LibraryFunction">call</span>(<span class="Variable">this</span>));
|
|
}
|
|
<span class="Keyword">return</span> _e;
|
|
};
|
|
</pre><button onclick='javascript: var _a, _b, _c, _d, countdown, egg_delivery, num;
|
|
countdown = (function() {
|
|
_a = []; _c = 10; _d = 1;
|
|
for (_b = 0, num = _c; (_c <= _d ? num <= _d : num >= _d); (_c <= _d ? num += 1 : num -= 1), _b++) {
|
|
_a.push(num);
|
|
}
|
|
return _a;
|
|
}).call(this);
|
|
egg_delivery = function egg_delivery() {
|
|
var _e, _f, _g, _h, dozen_eggs, i;
|
|
_e = []; _g = 0; _h = eggs.length;
|
|
for (_f = 0, i = _g; (_g <= _h ? i < _h : i > _h); (_g <= _h ? i += 12 : i -= 12), _f++) {
|
|
_e.push((function() {
|
|
dozen_eggs = eggs.slice(i, i + 12);
|
|
return deliver(new egg_carton(dozen));
|
|
}).call(this));
|
|
}
|
|
return _e;
|
|
};
|
|
;alert(countdown);'>run: countdown</button><br class='clear' /></div>
|
|
<p>
|
|
Comprehensions can also be used to iterate over the keys and values in
|
|
an object. Use <tt>of</tt> to signal comprehension over the properties of
|
|
an object instead of the values in an array.
|
|
</p>
|
|
<div class='code'><pre class="idle">years_old<span class="Keyword">:</span> {max<span class="Keyword">:</span> <span class="Number">10</span>, ida<span class="Keyword">:</span> <span class="Number">9</span>, tim<span class="Keyword">:</span> <span class="Number">11</span>}
|
|
|
|
ages<span class="Keyword">:</span> <span class="Keyword">for</span> child, age <span class="Keyword">of</span> years_old
|
|
child <span class="Keyword">+</span> <span class="String"><span class="String">"</span> is <span class="String">"</span></span> <span class="Keyword">+</span> age
|
|
</pre><pre class="idle"><span class="Storage">var</span> _a, _b, age, ages, child, years_old;
|
|
<span class="Storage">var</span> __hasProp <span class="Keyword">=</span> <span class="LibraryClassType">Object</span>.<span class="LibraryConstant">prototype</span>.hasOwnProperty;
|
|
years_old <span class="Keyword">=</span> {
|
|
max: <span class="Number">10</span>,
|
|
ida: <span class="Number">9</span>,
|
|
tim: <span class="Number">11</span>
|
|
};
|
|
ages <span class="Keyword">=</span> (<span class="Storage">function</span>() {
|
|
_a <span class="Keyword">=</span> []; _b <span class="Keyword">=</span> years_old;
|
|
<span class="Keyword">for</span> (child <span class="Keyword">in</span> _b) { <span class="Keyword">if</span> (__hasProp.<span class="LibraryFunction">call</span>(_b, child)) {
|
|
age <span class="Keyword">=</span> _b[child];
|
|
_a.<span class="LibraryFunction">push</span>(child <span class="Keyword">+</span> <span class="String"><span class="String">"</span> is <span class="String">"</span></span> <span class="Keyword">+</span> age);
|
|
}}
|
|
<span class="Keyword">return</span> _a;
|
|
}).<span class="LibraryFunction">call</span>(<span class="Variable">this</span>);
|
|
</pre><button onclick='javascript: var _a, _b, age, ages, child, years_old;
|
|
var __hasProp = Object.prototype.hasOwnProperty;
|
|
years_old = {
|
|
max: 10,
|
|
ida: 9,
|
|
tim: 11
|
|
};
|
|
ages = (function() {
|
|
_a = []; _b = years_old;
|
|
for (child in _b) { if (__hasProp.call(_b, child)) {
|
|
age = _b[child];
|
|
_a.push(child + " is " + age);
|
|
}}
|
|
return _a;
|
|
}).call(this);
|
|
;alert(ages.join(", "));'>run: ages.join(", ")</button><br class='clear' /></div>
|
|
|
|
<p>
|
|
<span id="slice_splice" class="bookmark"></span>
|
|
<b class="header">Array Slicing and Splicing with Ranges</b>
|
|
CoffeeScript borrows Ruby's
|
|
<a href="http://ruby-doc.org/core/classes/Range.html">range syntax</a>
|
|
for extracting slices of arrays. With two dots (<tt>3..5</tt>), the range
|
|
is inclusive: the first argument is the index of the first element in
|
|
the slice, and the second is the index of the last one. Three dots signify
|
|
a range that excludes the end.
|
|
</p>
|
|
<div class='code'><pre class="idle">numbers<span class="Keyword">:</span> [<span class="Number">0</span>, <span class="Number">1</span>, <span class="Number">2</span>, <span class="Number">3</span>, <span class="Number">4</span>, <span class="Number">5</span>, <span class="Number">6</span>, <span class="Number">7</span>, <span class="Number">8</span>, <span class="Number">9</span>]
|
|
|
|
three_to_six<span class="Keyword">:</span> numbers[<span class="Number">3</span>..<span class="Number">6</span>]
|
|
|
|
numbers_copy<span class="Keyword">:</span> numbers[<span class="Number">0</span>...numbers.length]
|
|
|
|
</pre><pre class="idle"><span class="Storage">var</span> numbers, numbers_copy, three_to_six;
|
|
numbers <span class="Keyword">=</span> [<span class="Number">0</span>, <span class="Number">1</span>, <span class="Number">2</span>, <span class="Number">3</span>, <span class="Number">4</span>, <span class="Number">5</span>, <span class="Number">6</span>, <span class="Number">7</span>, <span class="Number">8</span>, <span class="Number">9</span>];
|
|
three_to_six <span class="Keyword">=</span> numbers.<span class="LibraryFunction">slice</span>(<span class="Number">3</span>, <span class="Number">6</span> <span class="Keyword">+</span> <span class="Number">1</span>);
|
|
numbers_copy <span class="Keyword">=</span> numbers.<span class="LibraryFunction">slice</span>(<span class="Number">0</span>, numbers.<span class="LibraryConstant">length</span>);
|
|
</pre><button onclick='javascript: var numbers, numbers_copy, three_to_six;
|
|
numbers = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
|
|
three_to_six = numbers.slice(3, 6 + 1);
|
|
numbers_copy = numbers.slice(0, numbers.length);
|
|
;alert(numbers_copy);'>run: numbers_copy</button><br class='clear' /></div>
|
|
<p>
|
|
The same syntax can be used with assignment to replace a segment of an
|
|
array with new values (to splice it).
|
|
</p>
|
|
<div class='code'><pre class="idle">numbers<span class="Keyword">:</span> [<span class="Number">0</span>, <span class="Number">1</span>, <span class="Number">2</span>, <span class="Number">3</span>, <span class="Number">4</span>, <span class="Number">5</span>, <span class="Number">6</span>, <span class="Number">7</span>, <span class="Number">8</span>, <span class="Number">9</span>]
|
|
|
|
numbers[<span class="Number">3</span>..<span class="Number">6</span>]<span class="Keyword">:</span> [<span class="Keyword">-</span><span class="Number">3</span>, <span class="Keyword">-</span><span class="Number">4</span>, <span class="Keyword">-</span><span class="Number">5</span>, <span class="Keyword">-</span><span class="Number">6</span>]
|
|
|
|
|
|
</pre><pre class="idle"><span class="Storage">var</span> numbers;
|
|
numbers <span class="Keyword">=</span> [<span class="Number">0</span>, <span class="Number">1</span>, <span class="Number">2</span>, <span class="Number">3</span>, <span class="Number">4</span>, <span class="Number">5</span>, <span class="Number">6</span>, <span class="Number">7</span>, <span class="Number">8</span>, <span class="Number">9</span>];
|
|
numbers.splice.<span class="LibraryFunction">apply</span>(numbers, [<span class="Number">3</span>, <span class="Number">6</span> <span class="Keyword">-</span> <span class="Number">3</span> <span class="Keyword">+</span> <span class="Number">1</span>].<span class="LibraryFunction">concat</span>([<span class="Keyword">-</span><span class="Number">3</span>, <span class="Keyword">-</span><span class="Number">4</span>, <span class="Keyword">-</span><span class="Number">5</span>, <span class="Keyword">-</span><span class="Number">6</span>]));
|
|
</pre><button onclick='javascript: var numbers;
|
|
numbers = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
|
|
numbers.splice.apply(numbers, [3, 6 - 3 + 1].concat([-3, -4, -5, -6]));
|
|
;alert(numbers);'>run: numbers</button><br class='clear' /></div>
|
|
|
|
<p>
|
|
<span id="expressions" class="bookmark"></span>
|
|
<b class="header">Everything is an Expression (at least, as much as possible)</b>
|
|
You might have noticed how even though we don't add return statements
|
|
to CoffeeScript functions, they nonetheless return their final value.
|
|
The CoffeeScript compiler tries to make sure that all statements in the
|
|
language can be used as expressions. Watch how the <tt>return</tt> gets
|
|
pushed down into each possible branch of execution, in the function
|
|
below.
|
|
</p>
|
|
<div class='code'><pre class="idle"><span class="FunctionName">grade</span><span class="Keyword">:</span> <span class="FunctionArgument">(</span><span class="FunctionArgument">student</span><span class="FunctionArgument">)</span> <span class="Storage">-></span>
|
|
<span class="Keyword">if</span> student.excellent_work
|
|
<span class="String"><span class="String">"</span>A+<span class="String">"</span></span>
|
|
<span class="Keyword">else</span> <span class="Keyword">if</span> student.okay_stuff
|
|
<span class="Keyword">if</span> student.tried_hard <span class="Keyword">then</span> <span class="String"><span class="String">"</span>B<span class="String">"</span></span> <span class="Keyword">else</span> <span class="String"><span class="String">"</span>B-<span class="String">"</span></span>
|
|
<span class="Keyword">else</span>
|
|
<span class="String"><span class="String">"</span>C<span class="String">"</span></span>
|
|
|
|
eldest<span class="Keyword">:</span> <span class="Keyword">if</span> <span class="Number">24</span> <span class="Keyword">></span> <span class="Number">21</span> <span class="Keyword">then</span> <span class="String"><span class="String">"</span>Liz<span class="String">"</span></span> <span class="Keyword">else</span> <span class="String"><span class="String">"</span>Ike<span class="String">"</span></span>
|
|
</pre><pre class="idle"><span class="Storage">var</span> eldest, grade;
|
|
grade <span class="Keyword">=</span> <span class="Storage">function</span> <span class="FunctionName">grade</span>(<span class="FunctionArgument">student</span>) {
|
|
<span class="Keyword">if</span> (student.excellent_work) {
|
|
<span class="Keyword">return</span> <span class="String"><span class="String">"</span>A+<span class="String">"</span></span>;
|
|
} <span class="Keyword">else</span> <span class="Keyword">if</span> (student.okay_stuff) {
|
|
<span class="Keyword">if</span> (student.tried_hard) {
|
|
<span class="Keyword">return</span> <span class="String"><span class="String">"</span>B<span class="String">"</span></span>;
|
|
} <span class="Keyword">else</span> {
|
|
<span class="Keyword">return</span> <span class="String"><span class="String">"</span>B-<span class="String">"</span></span>;
|
|
}
|
|
} <span class="Keyword">else</span> {
|
|
<span class="Keyword">return</span> <span class="String"><span class="String">"</span>C<span class="String">"</span></span>;
|
|
}
|
|
};
|
|
eldest <span class="Keyword">=</span> <span class="Number">24</span> <span class="Keyword">></span> <span class="Number">21</span> ? <span class="String"><span class="String">"</span>Liz<span class="String">"</span></span> : <span class="String"><span class="String">"</span>Ike<span class="String">"</span></span>;
|
|
</pre><button onclick='javascript: var eldest, grade;
|
|
grade = function grade(student) {
|
|
if (student.excellent_work) {
|
|
return "A+";
|
|
} else if (student.okay_stuff) {
|
|
if (student.tried_hard) {
|
|
return "B";
|
|
} else {
|
|
return "B-";
|
|
}
|
|
} else {
|
|
return "C";
|
|
}
|
|
};
|
|
eldest = 24 > 21 ? "Liz" : "Ike";
|
|
;alert(eldest);'>run: eldest</button><br class='clear' /></div>
|
|
<p>
|
|
Even though functions will always return their final value, it's both possible
|
|
and encouraged to return early from a function body writing out the explicit
|
|
return (<tt>return value</tt>), when you know that you're done.
|
|
</p>
|
|
<p>
|
|
Because variable declarations occur at the top of scope, assignment can
|
|
be used within expressions, even for variables that haven't been seen before:
|
|
</p>
|
|
<div class='code'><pre class="idle">six<span class="Keyword">:</span> (one<span class="Keyword">:</span> <span class="Number">1</span>) <span class="Keyword">+</span> (two<span class="Keyword">:</span> <span class="Number">2</span>) <span class="Keyword">+</span> (three<span class="Keyword">:</span> <span class="Number">3</span>)
|
|
</pre><pre class="idle"><span class="Storage">var</span> one, six, three, two;
|
|
six <span class="Keyword">=</span> (one <span class="Keyword">=</span> <span class="Number">1</span>) <span class="Keyword">+</span> (two <span class="Keyword">=</span> <span class="Number">2</span>) <span class="Keyword">+</span> (three <span class="Keyword">=</span> <span class="Number">3</span>);
|
|
</pre><button onclick='javascript: var one, six, three, two;
|
|
six = (one = 1) + (two = 2) + (three = 3);
|
|
;alert(six);'>run: six</button><br class='clear' /></div>
|
|
<p>
|
|
Things that would otherwise be statements in JavaScript, when used
|
|
as part of an expression in CoffeeScript, are converted into expressions
|
|
by wrapping them in a closure. This lets you do useful things, like assign
|
|
the result of a comprehension to a variable:
|
|
</p>
|
|
<div class='code'><pre class="idle"><span class="Comment"><span class="Comment">#</span> The first ten global properties.</span>
|
|
|
|
globals<span class="Keyword">:</span> (name <span class="Keyword">for</span> name <span class="Keyword">of</span> window)[<span class="Number">0</span>...<span class="Number">10</span>]
|
|
</pre><pre class="idle"><span class="Storage">var</span> _a, _b, globals, name;
|
|
<span class="Storage">var</span> __hasProp <span class="Keyword">=</span> <span class="LibraryClassType">Object</span>.<span class="LibraryConstant">prototype</span>.hasOwnProperty;
|
|
<span class="Comment"><span class="Comment">//</span> The first ten global properties.</span>
|
|
globals <span class="Keyword">=</span> (<span class="Storage">function</span>() {
|
|
_a <span class="Keyword">=</span> []; _b <span class="Keyword">=</span> <span class="LibraryClassType">window</span>;
|
|
<span class="Keyword">for</span> (name <span class="Keyword">in</span> _b) { <span class="Keyword">if</span> (__hasProp.<span class="LibraryFunction">call</span>(_b, name)) {
|
|
_a.<span class="LibraryFunction">push</span>(name);
|
|
}}
|
|
<span class="Keyword">return</span> _a;
|
|
}).<span class="LibraryFunction">call</span>(<span class="Variable">this</span>).<span class="LibraryFunction">slice</span>(<span class="Number">0</span>, <span class="Number">10</span>);
|
|
</pre><button onclick='javascript: var _a, _b, globals, name;
|
|
var __hasProp = Object.prototype.hasOwnProperty;
|
|
// The first ten global properties.
|
|
globals = (function() {
|
|
_a = []; _b = window;
|
|
for (name in _b) { if (__hasProp.call(_b, name)) {
|
|
_a.push(name);
|
|
}}
|
|
return _a;
|
|
}).call(this).slice(0, 10);
|
|
;alert(globals);'>run: globals</button><br class='clear' /></div>
|
|
<p>
|
|
As well as silly things, like passing a <b>try/catch</b> statement directly
|
|
into a function call:
|
|
</p>
|
|
<div class='code'><pre class="idle">alert(
|
|
<span class="Keyword">try</span>
|
|
nonexistent <span class="Keyword">/</span> <span class="BuiltInConstant">undefined</span>
|
|
<span class="Keyword">catch</span> error
|
|
<span class="String"><span class="String">"</span>And the error is ... <span class="String">"</span></span> <span class="Keyword">+</span> error
|
|
)
|
|
</pre><pre class="idle"><span class="LibraryFunction">alert</span>((<span class="Storage">function</span>() {
|
|
<span class="Keyword">try</span> {
|
|
<span class="Keyword">return</span> nonexistent / undefined;
|
|
} <span class="Keyword">catch</span> (error) {
|
|
<span class="Keyword">return</span> <span class="String"><span class="String">"</span>And the error is ... <span class="String">"</span></span> <span class="Keyword">+</span> error;
|
|
}
|
|
}).<span class="LibraryFunction">call</span>(<span class="Variable">this</span>));
|
|
</pre><button onclick='javascript: alert((function() {
|
|
try {
|
|
return nonexistent / undefined;
|
|
} catch (error) {
|
|
return "And the error is ... " + error;
|
|
}
|
|
}).call(this));
|
|
;'>run</button><br class='clear' /></div>
|
|
<p>
|
|
There are a handful of statements in JavaScript that can't be meaningfully
|
|
converted into expressions, namely <tt>break</tt>, <tt>continue</tt>,
|
|
and <tt>return</tt>. If you make use of them within a block of code,
|
|
CoffeeScript won't try to perform the conversion.
|
|
</p>
|
|
|
|
<p>
|
|
<span id="existence" class="bookmark"></span>
|
|
<b class="header">The Existential Operator</b>
|
|
It's a little difficult to check for the existence of a variable in
|
|
JavaScript. <tt>if (variable) ...</tt> comes close, but fails for zero,
|
|
the empty string, and false. CoffeeScript's existential operator <tt>?</tt> returns true unless
|
|
a variable is <b>null</b> or <b>undefined</b>, which makes it analogous
|
|
to Ruby's <tt>nil?</tt>
|
|
</p>
|
|
<p>
|
|
It can also be used for safer conditional assignment than <tt>||=</tt>
|
|
provides, for cases where you may be handling numbers or strings.
|
|
</p>
|
|
<div class='code'><pre class="idle">solipsism<span class="Keyword">:</span> <span class="BuiltInConstant">true</span> <span class="Keyword">if</span> mind<span class="Keyword">?</span> <span class="Keyword">and</span> <span class="Keyword">not</span> world<span class="Keyword">?</span>
|
|
|
|
speed <span class="Keyword">?</span><span class="Keyword">=</span> <span class="Number">140</span>
|
|
|
|
|
|
|
|
|
|
|
|
</pre><pre class="idle"><span class="Storage">var</span> solipsism, speed;
|
|
<span class="Keyword">if</span> ((<span class="Keyword">typeof</span> mind <span class="Keyword">!</span><span class="Keyword">==</span> <span class="String"><span class="String">"</span>undefined<span class="String">"</span></span> <span class="Keyword">&</span><span class="Keyword">&</span> mind <span class="Keyword">!</span><span class="Keyword">==</span> <span class="BuiltInConstant">null</span>) <span class="Keyword">&</span><span class="Keyword">&</span> <span class="Keyword">!</span>(<span class="Keyword">typeof</span> world <span class="Keyword">!</span><span class="Keyword">==</span> <span class="String"><span class="String">"</span>undefined<span class="String">"</span></span> <span class="Keyword">&</span><span class="Keyword">&</span> world <span class="Keyword">!</span><span class="Keyword">==</span> <span class="BuiltInConstant">null</span>)) {
|
|
solipsism <span class="Keyword">=</span> <span class="BuiltInConstant">true</span>;
|
|
}
|
|
speed <span class="Keyword">=</span> (<span class="Keyword">typeof</span> speed <span class="Keyword">!</span><span class="Keyword">==</span> <span class="String"><span class="String">"</span>undefined<span class="String">"</span></span> <span class="Keyword">&</span><span class="Keyword">&</span> speed <span class="Keyword">!</span><span class="Keyword">==</span> <span class="BuiltInConstant">null</span>) ? speed : <span class="Number">140</span>;
|
|
</pre><button onclick='javascript: var solipsism, speed;
|
|
if ((typeof mind !== "undefined" && mind !== null) && !(typeof world !== "undefined" && world !== null)) {
|
|
solipsism = true;
|
|
}
|
|
speed = (typeof speed !== "undefined" && speed !== null) ? speed : 140;
|
|
;alert(speed);'>run: speed</button><br class='clear' /></div>
|
|
<p>
|
|
The accessor variant of the existential operator <tt>?.</tt> can be used to soak
|
|
up null references in a chain of properties. Use it instead
|
|
of the dot accessor <tt>.</tt> in cases where the base value may be <b>null</b>
|
|
or <b>undefined</b>. If all of the properties exist then you'll get the expected
|
|
result, if the chain is broken, <b>undefined</b> is returned instead of
|
|
the <b>TypeError</b> that would be raised otherwise.
|
|
</p>
|
|
<div class='code'><pre class="idle">lottery.draw_winner()<span class="Keyword">?</span>.address<span class="Keyword">?</span>.zipcode
|
|
</pre><pre class="idle"><span class="Storage">var</span> _a;
|
|
(_a <span class="Keyword">=</span> lottery.draw_winner()) <span class="Keyword">==</span> undefined ? undefined : _a.address <span class="Keyword">==</span> undefined ? undefined : _a.address.zipcode;
|
|
</pre><br class='clear' /></div>
|
|
<p>
|
|
Soaking up nulls is similar to Ruby's
|
|
<a href="http://andand.rubyforge.org/">andand gem</a>, and to the
|
|
<a href="http://groovy.codehaus.org/Operators#Operators-SafeNavigationOperator%28%3F.%29">safe navigation operator</a>
|
|
in Groovy.
|
|
</p>
|
|
|
|
<p>
|
|
<span id="classes" class="bookmark"></span>
|
|
<b class="header">Classes, Inheritance, and Super</b>
|
|
JavaScript's prototypal inheritance has always been a bit of a
|
|
brain-bender, with a whole family tree of libraries that provide a cleaner
|
|
syntax for classical inheritance on top of JavaScript's prototypes:
|
|
<a href="http://code.google.com/p/base2/">Base2</a>,
|
|
<a href="http://prototypejs.org/">Prototype.js</a>,
|
|
<a href="http://jsclass.jcoglan.com/">JS.Class</a>, etc.
|
|
The libraries provide syntactic sugar, but the built-in inheritance would
|
|
be completely usable if it weren't for a couple of small exceptions:
|
|
it's awkward to call <b>super</b> (the prototype object's
|
|
implementation of the current function), and it's awkward to correctly
|
|
set the prototype chain.
|
|
</p>
|
|
<p>
|
|
Instead of repetitively attaching functions to a prototype, CoffeeScript
|
|
provides a basic <tt>class</tt> structure that allows you to name your class,
|
|
set the superclass, assign prototypal properties, and define the constructor,
|
|
in a single assignable expression.
|
|
</p>
|
|
<div class='code'><pre class="idle"><span class="Storage">class</span> <span class="TypeName">Animal</span>
|
|
<span class="FunctionName">move</span><span class="Keyword">:</span> <span class="FunctionArgument">(</span><span class="FunctionArgument">meters</span><span class="FunctionArgument">)</span> <span class="Storage">-></span>
|
|
alert <span class="Variable">@name</span> <span class="Keyword">+</span> <span class="String"><span class="String">"</span> moved <span class="String">"</span></span> <span class="Keyword">+</span> meters <span class="Keyword">+</span> <span class="String"><span class="String">"</span>m.<span class="String">"</span></span>
|
|
|
|
<span class="Storage">class</span> <span class="TypeName">Snake</span><span class="InheritedClass"> <span class="Keyword">extends</span> Animal</span>
|
|
<span class="FunctionName">constructor</span><span class="Keyword">:</span> <span class="FunctionArgument">(</span><span class="FunctionArgument">name</span><span class="FunctionArgument">)</span> <span class="Storage">-></span>
|
|
<span class="Variable">@name</span><span class="Keyword">:</span> name
|
|
|
|
<span class="FunctionName">move</span><span class="Keyword">:</span> <span class="Storage">-></span>
|
|
alert <span class="String"><span class="String">"</span>Slithering...<span class="String">"</span></span>
|
|
<span class="Variable">super</span> <span class="Number">5</span>
|
|
|
|
<span class="Storage">class</span> <span class="TypeName">Horse</span><span class="InheritedClass"> <span class="Keyword">extends</span> Animal</span>
|
|
<span class="FunctionName">constructor</span><span class="Keyword">:</span> <span class="FunctionArgument">(</span><span class="FunctionArgument">name</span><span class="FunctionArgument">)</span> <span class="Storage">-></span>
|
|
<span class="Variable">@name</span><span class="Keyword">:</span> name
|
|
|
|
<span class="FunctionName">move</span><span class="Keyword">:</span> <span class="Storage">-></span>
|
|
alert <span class="String"><span class="String">"</span>Galloping...<span class="String">"</span></span>
|
|
<span class="Variable">super</span> <span class="Number">45</span>
|
|
|
|
sam<span class="Keyword">:</span> <span class="Keyword">new</span> <span class="TypeName">Snake</span> <span class="String"><span class="String">"</span>Sammy the Python<span class="String">"</span></span>
|
|
tom<span class="Keyword">:</span> <span class="Keyword">new</span> <span class="TypeName">Horse</span> <span class="String"><span class="String">"</span>Tommy the Palomino<span class="String">"</span></span>
|
|
|
|
sam.move()
|
|
tom.move()
|
|
|
|
|
|
|
|
|
|
</pre><pre class="idle"><span class="Storage">var</span> Animal, Horse, Snake, sam, tom;
|
|
<span class="Storage">var</span> <span class="FunctionName">__extends</span> = <span class="Storage">function</span>(<span class="FunctionArgument">child, parent</span>) {
|
|
<span class="Storage">var</span> <span class="FunctionName">ctor</span> = <span class="Storage">function</span>(){ };
|
|
<span class="LibraryClassType">ctor</span>.<span class="LibraryConstant">prototype</span> = parent.<span class="LibraryConstant">prototype</span>;
|
|
child.__superClass__ <span class="Keyword">=</span> parent.<span class="LibraryConstant">prototype</span>;
|
|
<span class="LibraryClassType">child</span>.<span class="LibraryConstant">prototype</span> = <span class="Keyword">new</span> <span class="TypeName">ctor</span>();
|
|
<span class="LibraryClassType">child</span>.<span class="LibraryConstant">prototype</span>.<span class="FunctionName">constructor</span> = child;
|
|
};
|
|
Animal <span class="Keyword">=</span> <span class="Storage">function</span> <span class="FunctionName">Animal</span>() { };
|
|
<span class="LibraryClassType">Animal</span>.<span class="LibraryConstant">prototype</span>.<span class="FunctionName">move</span> = <span class="Storage">function</span> <span class="FunctionName">move</span>(<span class="FunctionArgument">meters</span>) {
|
|
<span class="Keyword">return</span> <span class="LibraryFunction">alert</span>(<span class="Variable">this</span>.<span class="LibraryConstant">name</span> <span class="Keyword">+</span> <span class="String"><span class="String">"</span> moved <span class="String">"</span></span> <span class="Keyword">+</span> meters <span class="Keyword">+</span> <span class="String"><span class="String">"</span>m.<span class="String">"</span></span>);
|
|
};
|
|
Snake <span class="Keyword">=</span> <span class="Storage">function</span> <span class="FunctionName">Snake</span>(<span class="FunctionArgument">name</span>) {
|
|
<span class="Variable">this</span>.<span class="LibraryConstant">name</span> <span class="Keyword">=</span> name;
|
|
<span class="Keyword">return</span> <span class="Variable">this</span>;
|
|
};
|
|
__extends(Snake, Animal);
|
|
<span class="LibraryClassType">Snake</span>.<span class="LibraryConstant">prototype</span>.<span class="FunctionName">move</span> = <span class="Storage">function</span> <span class="FunctionName">move</span>() {
|
|
<span class="LibraryFunction">alert</span>(<span class="String"><span class="String">"</span>Slithering...<span class="String">"</span></span>);
|
|
<span class="Keyword">return</span> Snake.__superClass__.move.<span class="LibraryFunction">call</span>(<span class="Variable">this</span>, <span class="Number">5</span>);
|
|
};
|
|
Horse <span class="Keyword">=</span> <span class="Storage">function</span> <span class="FunctionName">Horse</span>(<span class="FunctionArgument">name</span>) {
|
|
<span class="Variable">this</span>.<span class="LibraryConstant">name</span> <span class="Keyword">=</span> name;
|
|
<span class="Keyword">return</span> <span class="Variable">this</span>;
|
|
};
|
|
__extends(Horse, Animal);
|
|
<span class="LibraryClassType">Horse</span>.<span class="LibraryConstant">prototype</span>.<span class="FunctionName">move</span> = <span class="Storage">function</span> <span class="FunctionName">move</span>() {
|
|
<span class="LibraryFunction">alert</span>(<span class="String"><span class="String">"</span>Galloping...<span class="String">"</span></span>);
|
|
<span class="Keyword">return</span> Horse.__superClass__.move.<span class="LibraryFunction">call</span>(<span class="Variable">this</span>, <span class="Number">45</span>);
|
|
};
|
|
sam <span class="Keyword">=</span> <span class="Keyword">new</span> <span class="TypeName">Snake</span>(<span class="String"><span class="String">"</span>Sammy the Python<span class="String">"</span></span>);
|
|
tom <span class="Keyword">=</span> <span class="Keyword">new</span> <span class="TypeName">Horse</span>(<span class="String"><span class="String">"</span>Tommy the Palomino<span class="String">"</span></span>);
|
|
sam.move();
|
|
tom.move();
|
|
</pre><button onclick='javascript: var Animal, Horse, Snake, sam, tom;
|
|
var __extends = function(child, parent) {
|
|
var ctor = function(){ };
|
|
ctor.prototype = parent.prototype;
|
|
child.__superClass__ = parent.prototype;
|
|
child.prototype = new ctor();
|
|
child.prototype.constructor = child;
|
|
};
|
|
Animal = function Animal() { };
|
|
Animal.prototype.move = function move(meters) {
|
|
return alert(this.name + " moved " + meters + "m.");
|
|
};
|
|
Snake = function Snake(name) {
|
|
this.name = name;
|
|
return this;
|
|
};
|
|
__extends(Snake, Animal);
|
|
Snake.prototype.move = function move() {
|
|
alert("Slithering...");
|
|
return Snake.__superClass__.move.call(this, 5);
|
|
};
|
|
Horse = function Horse(name) {
|
|
this.name = name;
|
|
return this;
|
|
};
|
|
__extends(Horse, Animal);
|
|
Horse.prototype.move = function move() {
|
|
alert("Galloping...");
|
|
return Horse.__superClass__.move.call(this, 45);
|
|
};
|
|
sam = new Snake("Sammy the Python");
|
|
tom = new Horse("Tommy the Palomino");
|
|
sam.move();
|
|
tom.move();
|
|
;'>run</button><br class='clear' /></div>
|
|
<p>
|
|
If structuring your prototypes classically isn't your cup of tea, CoffeeScript
|
|
provides a couple of lower-level conveniences. The <tt>extends</tt> operator
|
|
helps with proper prototype setup, <tt>::</tt> gives you
|
|
quick access to an object's prototype, and <tt>super()</tt>
|
|
is converted into a call against the immediate ancestor's method of the same name.
|
|
</p>
|
|
<div class='code'><pre class="idle"><span class="FunctionName">String::dasherize</span><span class="Keyword">:</span> <span class="Storage">-></span>
|
|
<span class="Variable">this</span>.replace(<span class="String"><span class="String">/</span>_<span class="String">/</span>g</span>, <span class="String"><span class="String">"</span>-<span class="String">"</span></span>)
|
|
</pre><pre class="idle"><span class="LibraryClassType">String</span>.<span class="LibraryConstant">prototype</span>.<span class="FunctionName">dasherize</span> = <span class="Storage">function</span> <span class="FunctionName">dasherize</span>() {
|
|
<span class="Keyword">return</span> <span class="Variable">this</span>.<span class="LibraryFunction">replace</span>(<span class="String"><span class="String">/</span>_<span class="String">/</span>g</span>, <span class="String"><span class="String">"</span>-<span class="String">"</span></span>);
|
|
};
|
|
</pre><button onclick='javascript: String.prototype.dasherize = function dasherize() {
|
|
return this.replace(/_/g, "-");
|
|
};
|
|
;alert("one_two".dasherize());'>run: "one_two".dasherize()</button><br class='clear' /></div>
|
|
<p>
|
|
Finally, you may assign Class-level (static) properties within a class
|
|
definition by using<br /><tt>@property: value</tt>
|
|
</p>
|
|
|
|
<p>
|
|
<span id="pattern_matching" class="bookmark"></span>
|
|
<b class="header">Pattern Matching (Destructuring Assignment)</b>
|
|
To make extracting values from complex arrays and objects more convenient,
|
|
CoffeeScript implements ECMAScript Harmony's proposed
|
|
<a href="http://wiki.ecmascript.org/doku.php?id=harmony:destructuring">destructuring assignment</a>
|
|
syntax. When you assign an array or object literal to a value, CoffeeScript
|
|
breaks up and matches both sides against each other, assigning the values
|
|
on the right to the variables on the left. In the simplest case, it can be
|
|
used for parallel assignment:
|
|
</p>
|
|
<div class='code'><pre class="idle">bait<span class="Keyword">:</span> <span class="Number">1000</span>
|
|
and_switch<span class="Keyword">:</span> <span class="Number">0</span>
|
|
|
|
<span class="Keyword">[</span>bait, and_switch<span class="Keyword">]:</span> [and_switch, bait]
|
|
</pre><pre class="idle"><span class="Storage">var</span> _a, and_switch, bait;
|
|
bait <span class="Keyword">=</span> <span class="Number">1000</span>;
|
|
and_switch <span class="Keyword">=</span> <span class="Number">0</span>;
|
|
_a <span class="Keyword">=</span> [and_switch, bait];
|
|
bait <span class="Keyword">=</span> _a[<span class="Number">0</span>];
|
|
and_switch <span class="Keyword">=</span> _a[<span class="Number">1</span>];
|
|
</pre><button onclick='javascript: var _a, and_switch, bait;
|
|
bait = 1000;
|
|
and_switch = 0;
|
|
_a = [and_switch, bait];
|
|
bait = _a[0];
|
|
and_switch = _a[1];
|
|
;alert(bait);'>run: bait</button><br class='clear' /></div>
|
|
<p>
|
|
But it's also helpful for dealing with functions that return multiple
|
|
values.
|
|
</p>
|
|
<div class='code'><pre class="idle"><span class="FunctionName">weather_report</span><span class="Keyword">:</span> <span class="FunctionArgument">(</span><span class="FunctionArgument">location</span><span class="FunctionArgument">)</span> <span class="Storage">-></span>
|
|
<span class="Comment"><span class="Comment">#</span> Make an Ajax request to fetch the weather...</span>
|
|
[location, <span class="Number">72</span>, <span class="String"><span class="String">"</span>Mostly Sunny<span class="String">"</span></span>]
|
|
|
|
<span class="Keyword">[</span>city, temp, forecast<span class="Keyword">]:</span> weather_report <span class="String"><span class="String">"</span>Berkeley, CA<span class="String">"</span></span>
|
|
</pre><pre class="idle"><span class="Storage">var</span> _a, city, forecast, temp, weather_report;
|
|
weather_report <span class="Keyword">=</span> <span class="Storage">function</span> <span class="FunctionName">weather_report</span>(<span class="FunctionArgument">location</span>) {
|
|
<span class="Comment"><span class="Comment">//</span> Make an Ajax request to fetch the weather...</span>
|
|
<span class="Keyword">return</span> [location, <span class="Number">72</span>, <span class="String"><span class="String">"</span>Mostly Sunny<span class="String">"</span></span>];
|
|
};
|
|
_a <span class="Keyword">=</span> weather_report(<span class="String"><span class="String">"</span>Berkeley, CA<span class="String">"</span></span>);
|
|
city <span class="Keyword">=</span> _a[<span class="Number">0</span>];
|
|
temp <span class="Keyword">=</span> _a[<span class="Number">1</span>];
|
|
forecast <span class="Keyword">=</span> _a[<span class="Number">2</span>];
|
|
</pre><button onclick='javascript: var _a, city, forecast, temp, weather_report;
|
|
weather_report = function weather_report(location) {
|
|
// Make an Ajax request to fetch the weather...
|
|
return [location, 72, "Mostly Sunny"];
|
|
};
|
|
_a = weather_report("Berkeley, CA");
|
|
city = _a[0];
|
|
temp = _a[1];
|
|
forecast = _a[2];
|
|
;alert(forecast);'>run: forecast</button><br class='clear' /></div>
|
|
<p>
|
|
Pattern matching can be used with any depth of array and object nesting,
|
|
to help pull out deeply nested properties.
|
|
</p>
|
|
<div class='code'><pre class="idle">futurists<span class="Keyword">:</span> {
|
|
sculptor<span class="Keyword">:</span> <span class="String"><span class="String">"</span>Umberto Boccioni<span class="String">"</span></span>
|
|
painter<span class="Keyword">:</span> <span class="String"><span class="String">"</span>Vladimir Burliuk<span class="String">"</span></span>
|
|
poet<span class="Keyword">:</span> {
|
|
name<span class="Keyword">:</span> <span class="String"><span class="String">"</span>F.T. Marinetti<span class="String">"</span></span>
|
|
address<span class="Keyword">:</span> [
|
|
<span class="String"><span class="String">"</span>Via Roma 42R<span class="String">"</span></span>
|
|
<span class="String"><span class="String">"</span>Bellagio, Italy 22021<span class="String">"</span></span>
|
|
]
|
|
}
|
|
}
|
|
|
|
{poet<span class="Keyword">:</span> {name<span class="Keyword">:</span> poet, address<span class="Keyword">:</span> [street, city]}}<span class="Keyword">:</span> futurists
|
|
</pre><pre class="idle"><span class="Storage">var</span> _a, _b, _c, city, futurists, poet, street;
|
|
futurists <span class="Keyword">=</span> {
|
|
sculptor: <span class="String"><span class="String">"</span>Umberto Boccioni<span class="String">"</span></span>,
|
|
painter: <span class="String"><span class="String">"</span>Vladimir Burliuk<span class="String">"</span></span>,
|
|
poet: {
|
|
name: <span class="String"><span class="String">"</span>F.T. Marinetti<span class="String">"</span></span>,
|
|
address: [<span class="String"><span class="String">"</span>Via Roma 42R<span class="String">"</span></span>, <span class="String"><span class="String">"</span>Bellagio, Italy 22021<span class="String">"</span></span>]
|
|
}
|
|
};
|
|
_a <span class="Keyword">=</span> futurists;
|
|
_b <span class="Keyword">=</span> _a.poet;
|
|
poet <span class="Keyword">=</span> _b.<span class="LibraryConstant">name</span>;
|
|
_c <span class="Keyword">=</span> _b.address;
|
|
street <span class="Keyword">=</span> _c[<span class="Number">0</span>];
|
|
city <span class="Keyword">=</span> _c[<span class="Number">1</span>];
|
|
</pre><button onclick='javascript: var _a, _b, _c, city, futurists, poet, street;
|
|
futurists = {
|
|
sculptor: "Umberto Boccioni",
|
|
painter: "Vladimir Burliuk",
|
|
poet: {
|
|
name: "F.T. Marinetti",
|
|
address: ["Via Roma 42R", "Bellagio, Italy 22021"]
|
|
}
|
|
};
|
|
_a = futurists;
|
|
_b = _a.poet;
|
|
poet = _b.name;
|
|
_c = _b.address;
|
|
street = _c[0];
|
|
city = _c[1];
|
|
;alert(poet + " — " + street);'>run: poet + " — " + street</button><br class='clear' /></div>
|
|
<p>
|
|
Pattern matching can even be combined with splats.
|
|
</p>
|
|
<div class='code'><pre class="idle">tag<span class="Keyword">:</span> <span class="String"><span class="String">"</span><impossible><span class="String">"</span></span>
|
|
|
|
<span class="Keyword">[</span>open, contents..., close<span class="Keyword">]:</span> tag.split(<span class="String"><span class="String">"</span><span class="String">"</span></span>)
|
|
|
|
|
|
|
|
|
|
</pre><pre class="idle"><span class="Storage">var</span> _a, close, contents, open, tag;
|
|
<span class="Storage">var</span> __slice <span class="Keyword">=</span> <span class="LibraryClassType">Array</span>.<span class="LibraryConstant">prototype</span>.slice;
|
|
tag <span class="Keyword">=</span> <span class="String"><span class="String">"</span><impossible><span class="String">"</span></span>;
|
|
_a <span class="Keyword">=</span> tag.<span class="LibraryFunction">split</span>(<span class="String"><span class="String">"</span><span class="String">"</span></span>);
|
|
open <span class="Keyword">=</span> _a[<span class="Number">0</span>];
|
|
contents <span class="Keyword">=</span> __slice.<span class="LibraryFunction">call</span>(_a, <span class="Number">1</span>, _a.<span class="LibraryConstant">length</span> <span class="Keyword">-</span> <span class="Number">1</span>);
|
|
close <span class="Keyword">=</span> _a[_a.<span class="LibraryConstant">length</span> <span class="Keyword">-</span> <span class="Number">1</span>];
|
|
</pre><button onclick='javascript: var _a, close, contents, open, tag;
|
|
var __slice = Array.prototype.slice;
|
|
tag = "<impossible>";
|
|
_a = tag.split("");
|
|
open = _a[0];
|
|
contents = __slice.call(_a, 1, _a.length - 1);
|
|
close = _a[_a.length - 1];
|
|
;alert(contents.join(""));'>run: contents.join("")</button><br class='clear' /></div>
|
|
|
|
<p>
|
|
<span id="fat_arrow" class="bookmark"></span>
|
|
<b class="header">Function binding</b>
|
|
In JavaScript, the <tt>this</tt> keyword is dynamically scoped to mean the
|
|
object that the current function is attached to. If you pass a function as
|
|
as callback, or attach it to a different object, the original value of <tt>this</tt>
|
|
will be lost. If you're not familiar with this behavior,
|
|
<a href="http://www.digital-web.com/articles/scope_in_javascript/">this Digital Web article</a>
|
|
gives a good overview of the quirks.
|
|
</p>
|
|
<p>
|
|
The fat arrow <tt>=></tt> can be used to both define a function, and to bind
|
|
it to the current value of <tt>this</tt>, right on the spot. This is helpful
|
|
when using callback-based libraries like Prototype or jQuery, for creating
|
|
iterator functions to pass to <tt>each</tt>, or event-handler functions
|
|
to use with <tt>bind</tt>. Functions created with the fat arrow are able to access
|
|
properties of the <tt>this</tt> where they're defined.
|
|
</p>
|
|
<div class='code'><pre class="idle"><span class="FunctionName">Account</span><span class="Keyword">:</span> <span class="FunctionArgument">(</span><span class="FunctionArgument">customer, cart</span><span class="FunctionArgument">)</span> <span class="Storage">-></span>
|
|
<span class="Variable">@customer</span><span class="Keyword">:</span> customer
|
|
<span class="Variable">@cart</span><span class="Keyword">:</span> cart
|
|
|
|
$(<span class="String"><span class="String">'</span>.shopping_cart<span class="String">'</span></span>).bind <span class="String"><span class="String">'</span>click<span class="String">'</span></span>, <span class="FunctionArgument">(</span><span class="FunctionArgument">event</span><span class="FunctionArgument">)</span> <span class="Storage">=></span>
|
|
<span class="Variable">@customer</span>.purchase <span class="Variable">@cart</span>
|
|
</pre><pre class="idle"><span class="Storage">var</span> Account;
|
|
<span class="Storage">var</span> __slice <span class="Keyword">=</span> <span class="LibraryClassType">Array</span>.<span class="LibraryConstant">prototype</span>.slice, <span class="FunctionName">__bind</span> = <span class="Storage">function</span>(<span class="FunctionArgument">func, obj, args</span>) {
|
|
<span class="Keyword">return</span> <span class="Storage">function</span>() {
|
|
<span class="Keyword">return</span> func.<span class="LibraryFunction">apply</span>(obj <span class="Keyword">||</span> {}, args ? args.<span class="LibraryFunction">concat</span>(__slice.<span class="LibraryFunction">call</span>(arguments, <span class="Number">0</span>)) : arguments);
|
|
};
|
|
};
|
|
Account <span class="Keyword">=</span> <span class="Storage">function</span> <span class="FunctionName">Account</span>(<span class="FunctionArgument">customer, cart</span>) {
|
|
<span class="Variable">this</span>.customer <span class="Keyword">=</span> customer;
|
|
<span class="Variable">this</span>.cart <span class="Keyword">=</span> cart;
|
|
<span class="Keyword">return</span> <span class="Keyword">$</span>(<span class="String"><span class="String">'</span>.shopping_cart<span class="String">'</span></span>).bind(<span class="String"><span class="String">'</span>click<span class="String">'</span></span>, __bind(<span class="Storage">function</span>(<span class="LibraryClassType">event</span>) {
|
|
<span class="Keyword">return</span> <span class="Variable">this</span>.customer.purchase(<span class="Variable">this</span>.cart);
|
|
}, <span class="Variable">this</span>));
|
|
};
|
|
</pre><br class='clear' /></div>
|
|
<p>
|
|
If we had used <tt>-></tt> in the callback above, <tt>@customer</tt> would
|
|
have referred to the undefined "customer" property of the DOM element,
|
|
and trying to call <tt>purchase()</tt> on it would have raised an exception.
|
|
</p>
|
|
<p>
|
|
If you have more custom needs for function binding, CoffeeScript includes
|
|
the <tt><-</tt> bind operator, which works the same as ECMAScript 5
|
|
and Prototype.js's <tt>Function#bind</tt>. The first argument is the <tt>this</tt>
|
|
value, and the remainder are curried arguments. In the example below,
|
|
we curry a jQuery request for a URL, and then execute the bound function
|
|
with the missing callback argument.
|
|
</p>
|
|
<div class='code'><pre class="idle">url<span class="Keyword">:</span> <span class="String"><span class="String">"</span>documentation/coffee/binding.coffee<span class="String">"</span></span>
|
|
|
|
get_source<span class="Keyword">:</span> jQuery.get <span class="Keyword"><</span><span class="Keyword">-</span> jQuery, url
|
|
|
|
get_source <span class="FunctionArgument">(</span><span class="FunctionArgument">response</span><span class="FunctionArgument">)</span> <span class="Storage">-></span> alert response
|
|
</pre><pre class="idle"><span class="Storage">var</span> get_source, url;
|
|
<span class="Storage">var</span> __slice <span class="Keyword">=</span> <span class="LibraryClassType">Array</span>.<span class="LibraryConstant">prototype</span>.slice, <span class="FunctionName">__bind</span> = <span class="Storage">function</span>(<span class="FunctionArgument">func, obj, args</span>) {
|
|
<span class="Keyword">return</span> <span class="Storage">function</span>() {
|
|
<span class="Keyword">return</span> func.<span class="LibraryFunction">apply</span>(obj <span class="Keyword">||</span> {}, args ? args.<span class="LibraryFunction">concat</span>(__slice.<span class="LibraryFunction">call</span>(arguments, <span class="Number">0</span>)) : arguments);
|
|
};
|
|
};
|
|
url <span class="Keyword">=</span> <span class="String"><span class="String">"</span>documentation/coffee/binding.coffee<span class="String">"</span></span>;
|
|
get_source <span class="Keyword">=</span> __bind(jQuery.get, jQuery, [url]);
|
|
get_source(<span class="Storage">function</span>(response) {
|
|
<span class="Keyword">return</span> <span class="LibraryFunction">alert</span>(response);
|
|
});
|
|
</pre><button onclick='javascript: var get_source, url;
|
|
var __slice = Array.prototype.slice, __bind = function(func, obj, args) {
|
|
return function() {
|
|
return func.apply(obj || {}, args ? args.concat(__slice.call(arguments, 0)) : arguments);
|
|
};
|
|
};
|
|
url = "documentation/coffee/binding.coffee";
|
|
get_source = __bind(jQuery.get, jQuery, [url]);
|
|
get_source(function(response) {
|
|
return alert(response);
|
|
});
|
|
;'>run</button><br class='clear' /></div>
|
|
|
|
<p>
|
|
<span id="embedded" class="bookmark"></span>
|
|
<b class="header">Embedded JavaScript</b>
|
|
Hopefully, you'll never need to use it, but if you ever need to intersperse
|
|
snippets of JavaScript within your CoffeeScript, you can
|
|
use backticks to pass it straight through.
|
|
</p>
|
|
<div class='code'><pre class="idle">hi<span class="Keyword">:</span> <span class="String"><span class="String">`</span>function() {</span>
|
|
<span class="String"> return [document.title, "Hello JavaScript"].join(": ");</span>
|
|
<span class="String">}<span class="String">`</span></span>
|
|
|
|
|
|
</pre><pre class="idle"><span class="Storage">var</span> hi;
|
|
<span class="FunctionName">hi</span> = <span class="Storage">function</span>() {
|
|
<span class="Keyword">return</span> [<span class="LibraryClassType">document</span>.<span class="LibraryConstant">title</span>, <span class="String"><span class="String">"</span>Hello JavaScript<span class="String">"</span></span>].<span class="LibraryFunction">join</span>(<span class="String"><span class="String">"</span>: <span class="String">"</span></span>);
|
|
};
|
|
</pre><button onclick='javascript: var hi;
|
|
hi = function() {
|
|
return [document.title, "Hello JavaScript"].join(": ");
|
|
};
|
|
;alert(hi());'>run: hi()</button><br class='clear' /></div>
|
|
|
|
<p>
|
|
<span id="switch" class="bookmark"></span>
|
|
<b class="header">Switch/When/Else</b>
|
|
<b>Switch</b> statements in JavaScript are rather broken. You can only
|
|
do comparisons based on string equality, and need to remember to <b>break</b> at the end of
|
|
every <b>case</b> statement to avoid accidentally falling through to
|
|
the default case. CoffeeScript compiles <b>switch</b> statements into JavaScript if-else chains, allowing you to
|
|
compare any object (via <b>===</b>), preventing fall-through, and resulting
|
|
in a returnable, assignable expression. The format is: <tt>switch</tt> condition,
|
|
<tt>when</tt> clauses, <tt>else</tt> the default case.
|
|
</p>
|
|
<p>
|
|
As in Ruby, <b>switch</b> statements in CoffeeScript can take multiple
|
|
values for each <b>when</b> clause. If any of the values match, the clause
|
|
runs.
|
|
</p>
|
|
<div class='code'><pre class="idle"><span class="Keyword">switch</span> day
|
|
<span class="Keyword">when</span> <span class="String"><span class="String">"</span>Mon<span class="String">"</span></span> <span class="Keyword">then</span> go_to_work()
|
|
<span class="Keyword">when</span> <span class="String"><span class="String">"</span>Tue<span class="String">"</span></span> <span class="Keyword">then</span> go_to_the_park()
|
|
<span class="Keyword">when</span> <span class="String"><span class="String">"</span>Thu<span class="String">"</span></span> <span class="Keyword">then</span> go_ice_fishing()
|
|
<span class="Keyword">when</span> <span class="String"><span class="String">"</span>Fri<span class="String">"</span></span>, <span class="String"><span class="String">"</span>Sat<span class="String">"</span></span>
|
|
<span class="Keyword">if</span> day <span class="Keyword">is</span> bingo_day
|
|
go_to_bingo()
|
|
go_dancing()
|
|
<span class="Keyword">when</span> <span class="String"><span class="String">"</span>Sun<span class="String">"</span></span> <span class="Keyword">then</span> go_to_church()
|
|
<span class="Keyword">else</span> go_to_work()
|
|
</pre><pre class="idle"><span class="Keyword">if</span> (day <span class="Keyword">===</span> <span class="String"><span class="String">"</span>Mon<span class="String">"</span></span>) {
|
|
go_to_work();
|
|
} <span class="Keyword">else</span> <span class="Keyword">if</span> (day <span class="Keyword">===</span> <span class="String"><span class="String">"</span>Tue<span class="String">"</span></span>) {
|
|
go_to_the_park();
|
|
} <span class="Keyword">else</span> <span class="Keyword">if</span> (day <span class="Keyword">===</span> <span class="String"><span class="String">"</span>Thu<span class="String">"</span></span>) {
|
|
go_ice_fishing();
|
|
} <span class="Keyword">else</span> <span class="Keyword">if</span> (day <span class="Keyword">===</span> <span class="String"><span class="String">"</span>Fri<span class="String">"</span></span> <span class="Keyword">||</span> day <span class="Keyword">===</span> <span class="String"><span class="String">"</span>Sat<span class="String">"</span></span>) {
|
|
<span class="Keyword">if</span> (day <span class="Keyword">===</span> bingo_day) {
|
|
go_to_bingo();
|
|
go_dancing();
|
|
}
|
|
} <span class="Keyword">else</span> <span class="Keyword">if</span> (day <span class="Keyword">===</span> <span class="String"><span class="String">"</span>Sun<span class="String">"</span></span>) {
|
|
go_to_church();
|
|
} <span class="Keyword">else</span> {
|
|
go_to_work();
|
|
}
|
|
</pre><br class='clear' /></div>
|
|
|
|
<p>
|
|
<span id="try" class="bookmark"></span>
|
|
<b class="header">Try/Catch/Finally</b>
|
|
Try/catch statements are just about the same as JavaScript (although
|
|
they work as expressions).
|
|
</p>
|
|
<div class='code'><pre class="idle"><span class="Keyword">try</span>
|
|
all_hell_breaks_loose()
|
|
cats_and_dogs_living_together()
|
|
<span class="Keyword">catch</span> error
|
|
print error
|
|
<span class="Keyword">finally</span>
|
|
clean_up()
|
|
</pre><pre class="idle"><span class="Keyword">try</span> {
|
|
all_hell_breaks_loose();
|
|
cats_and_dogs_living_together();
|
|
} <span class="Keyword">catch</span> (error) {
|
|
<span class="LibraryFunction">print</span>(error);
|
|
} <span class="Keyword">finally</span> {
|
|
clean_up();
|
|
}
|
|
</pre><br class='clear' /></div>
|
|
|
|
<p>
|
|
<span id="comparisons" class="bookmark"></span>
|
|
<b class="header">Chained Comparisons</b>
|
|
CoffeeScript borrows
|
|
<a href="http://docs.python.org/reference/expressions.html#notin">chained comparisons</a>
|
|
from Python — making it easy to test if a value falls within a
|
|
certain range.
|
|
</p>
|
|
<div class='code'><pre class="idle">cholesterol<span class="Keyword">:</span> <span class="Number">127</span>
|
|
|
|
healthy<span class="Keyword">:</span> <span class="Number">200</span> <span class="Keyword">></span> cholesterol <span class="Keyword">></span> <span class="Number">60</span>
|
|
|
|
|
|
</pre><pre class="idle"><span class="Storage">var</span> cholesterol, healthy;
|
|
cholesterol <span class="Keyword">=</span> <span class="Number">127</span>;
|
|
healthy <span class="Keyword">=</span> (<span class="Number">200</span> <span class="Keyword">></span> cholesterol) <span class="Keyword">&</span><span class="Keyword">&</span> (cholesterol <span class="Keyword">></span> <span class="Number">60</span>);
|
|
</pre><button onclick='javascript: var cholesterol, healthy;
|
|
cholesterol = 127;
|
|
healthy = (200 > cholesterol) && (cholesterol > 60);
|
|
;alert(healthy);'>run: healthy</button><br class='clear' /></div>
|
|
|
|
<p>
|
|
<span id="interpolation" class="bookmark"></span>
|
|
<b class="header">String and RegExp Interpolation</b>
|
|
A version of <a href="http://wiki.ecmascript.org/doku.php?id=strawman:string_interpolation">ECMAScript Harmony's proposed string interpolation</a>
|
|
is included in CoffeeScript. Simple variables can be included by marking
|
|
them with a dollar sign.
|
|
</p>
|
|
<div class='code'><pre class="idle">author<span class="Keyword">:</span> <span class="String"><span class="String">"</span>Wittgenstein<span class="String">"</span></span>
|
|
quote<span class="Keyword">:</span> <span class="String"><span class="String">"</span>A picture is a fact. -- <span class="String"><span class="String">$</span>author</span><span class="String">"</span></span>
|
|
</pre><pre class="idle"><span class="Storage">var</span> author, quote;
|
|
author <span class="Keyword">=</span> <span class="String"><span class="String">"</span>Wittgenstein<span class="String">"</span></span>;
|
|
quote <span class="Keyword">=</span> (<span class="String"><span class="String">"</span>A picture is a fact. -- <span class="String">"</span></span> <span class="Keyword">+</span> author);
|
|
</pre><button onclick='javascript: var author, quote;
|
|
author = "Wittgenstein";
|
|
quote = ("A picture is a fact. -- " + author);
|
|
;alert(quote);'>run: quote</button><br class='clear' /></div>
|
|
<p>
|
|
And arbitrary expressions can be interpolated by using brackets <tt>${ ... }</tt><br />
|
|
Interpolation works the same way within regular expressions.
|
|
</p>
|
|
<div class='code'><pre class="idle">sentence<span class="Keyword">:</span> <span class="String"><span class="String">"</span><span class="String"><span class="String">${</span> <span class="Number">22</span> <span class="Keyword">/</span> <span class="Number">7</span> <span class="String">}</span></span> is a decent approximation of π<span class="String">"</span></span>
|
|
|
|
sep<span class="Keyword">:</span> <span class="String"><span class="String">"</span>[.<span class="UserDefinedConstant">\\</span>/<span class="UserDefinedConstant">\\</span>- ]<span class="String">"</span></span>
|
|
dates<span class="Keyword">:</span><span class="String"> <span class="String">/</span><span class="UserDefinedConstant">\d</span>+<span class="String"><span class="String">$</span>sep</span><span class="UserDefinedConstant">\d</span>+<span class="String"><span class="String">$</span>sep</span><span class="UserDefinedConstant">\d</span>+<span class="String">/</span>g</span>
|
|
|
|
|
|
</pre><pre class="idle"><span class="Storage">var</span> dates, sentence, sep;
|
|
sentence <span class="Keyword">=</span> (<span class="String"><span class="String">"</span><span class="String">"</span></span> <span class="Keyword">+</span> (<span class="Number">22</span> / <span class="Number">7</span>) <span class="Keyword">+</span> <span class="String"><span class="String">"</span> is a decent approximation of π<span class="String">"</span></span>);
|
|
sep <span class="Keyword">=</span> <span class="String"><span class="String">"</span>[.<span class="UserDefinedConstant">\\</span>/<span class="UserDefinedConstant">\\</span>- ]<span class="String">"</span></span>;
|
|
dates <span class="Keyword">=</span> (<span class="Keyword">new</span> <span class="TypeName">RegExp</span>((<span class="String"><span class="String">"</span><span class="UserDefinedConstant">\\</span>d+<span class="String">"</span></span> <span class="Keyword">+</span> sep <span class="Keyword">+</span> <span class="String"><span class="String">"</span><span class="UserDefinedConstant">\\</span>d+<span class="String">"</span></span> <span class="Keyword">+</span> sep <span class="Keyword">+</span> <span class="String"><span class="String">"</span><span class="UserDefinedConstant">\\</span>d+<span class="String">"</span></span>), <span class="String"><span class="String">"</span>g<span class="String">"</span></span>));
|
|
</pre><button onclick='javascript: var dates, sentence, sep;
|
|
sentence = ("" + (22 / 7) + " is a decent approximation of π");
|
|
sep = "[.\\/\\- ]";
|
|
dates = (new RegExp(("\\d+" + sep + "\\d+" + sep + "\\d+"), "g"));
|
|
;alert(sentence);'>run: sentence</button><br class='clear' /></div>
|
|
|
|
<p>
|
|
<span id="strings" class="bookmark"></span>
|
|
<b class="header">Multiline Strings and Heredocs</b>
|
|
Multiline strings are allowed in CoffeeScript.
|
|
</p>
|
|
<div class='code'><pre class="idle">moby_dick<span class="Keyword">:</span> <span class="String"><span class="String">"</span>Call me Ishmael. Some years ago --</span>
|
|
<span class="String">never mind how long precisely -- having little</span>
|
|
<span class="String">or no money in my purse, and nothing particular</span>
|
|
<span class="String">to interest me on shore, I thought I would sail</span>
|
|
<span class="String">about a little and see the watery part of the</span>
|
|
<span class="String">world...<span class="String">"</span></span>
|
|
|
|
|
|
</pre><pre class="idle"><span class="Storage">var</span> moby_dick;
|
|
moby_dick <span class="Keyword">=</span> <span class="String"><span class="String">"</span>Call me Ishmael. Some years ago -- \</span>
|
|
<span class="String">never mind how long precisely -- having little \</span>
|
|
<span class="String">or no money in my purse, and nothing particular \</span>
|
|
<span class="String">to interest me on shore, I thought I would sail \</span>
|
|
<span class="String">about a little and see the watery part of the \</span>
|
|
<span class="String">world...<span class="String">"</span></span>;
|
|
</pre><button onclick='javascript: var moby_dick;
|
|
moby_dick = "Call me Ishmael. Some years ago -- \
|
|
never mind how long precisely -- having little \
|
|
or no money in my purse, and nothing particular \
|
|
to interest me on shore, I thought I would sail \
|
|
about a little and see the watery part of the \
|
|
world...";
|
|
;alert(moby_dick);'>run: moby_dick</button><br class='clear' /></div>
|
|
<p>
|
|
Heredocs can be used to hold formatted or indentation-sensitive text
|
|
(or, if you just don't feel like escaping quotes and apostrophes). The
|
|
indentation level that begins the heredoc is maintained throughout, so
|
|
you can keep it all aligned with the body of your code.
|
|
</p>
|
|
<div class='code'><pre class="idle">html<span class="Keyword">:</span> <span class="String"><span class="String">'''</span></span>
|
|
<span class="String"> <strong></span>
|
|
<span class="String"> cup of coffeescript</span>
|
|
<span class="String"> </strong></span>
|
|
<span class="String"> <span class="String">'''</span></span>
|
|
</pre><pre class="idle"><span class="Storage">var</span> html;
|
|
html <span class="Keyword">=</span> <span class="String"><span class="String">'</span><strong><span class="UserDefinedConstant">\n</span> cup of coffeescript<span class="UserDefinedConstant">\n</span></strong><span class="String">'</span></span>;
|
|
</pre><br class='clear' /></div>
|
|
<p>
|
|
Double-quoted heredocs, like double-quoted strings, allow interpolation.
|
|
</p>
|
|
|
|
<h2>
|
|
<span id="cake" class="bookmark"></span>
|
|
Cake, and Cakefiles
|
|
</h2>
|
|
|
|
<p>
|
|
CoffeeScript includes a simple build system similar to Make and Rake. Naturally,
|
|
it's called Cake, and is used for the build and test tasks for the CoffeeScript
|
|
language itself. Tasks are defined in a file named <tt>Cakefile</tt>, and
|
|
can be invoked by running <tt>cake taskname</tt> from within the directory.
|
|
To print a list of all the tasks, just run <tt>cake</tt>.
|
|
</p>
|
|
|
|
<p>
|
|
Task definitions are written in CoffeeScript, so you can put arbitrary code
|
|
in your Cakefile. Define a task with a name, a long description, and the
|
|
function to invoke when the task is run. Here's a hypothetical task
|
|
that uses the Node.js API.
|
|
</p>
|
|
<div class='code'><pre class="idle">task <span class="String"><span class="String">'</span>test<span class="String">'</span></span>, <span class="String"><span class="String">'</span>run each of the unit tests<span class="String">'</span></span>, <span class="Storage">-></span>
|
|
<span class="Keyword">for</span> test <span class="Keyword">in</span> test_files
|
|
fs.readFile test, <span class="FunctionArgument">(</span><span class="FunctionArgument">err, code</span><span class="FunctionArgument">)</span> <span class="Storage">-></span> eval coffee.compile code
|
|
</pre><pre class="idle">task(<span class="String"><span class="String">'</span>test<span class="String">'</span></span>, <span class="String"><span class="String">'</span>run each of the unit tests<span class="String">'</span></span>, <span class="Storage">function</span>() {
|
|
<span class="Storage">var</span> _a, _b, _c, _d, test;
|
|
_a <span class="Keyword">=</span> []; _c <span class="Keyword">=</span> test_files;
|
|
<span class="Keyword">for</span> (_b <span class="Keyword">=</span> <span class="Number">0</span>, _d <span class="Keyword">=</span> _c.<span class="LibraryConstant">length</span>; _b <span class="Keyword"><</span> _d; _b<span class="Keyword">++</span>) {
|
|
test <span class="Keyword">=</span> _c[_b];
|
|
_a.<span class="LibraryFunction">push</span>(fs.readFile(test, <span class="Storage">function</span>(err, code) {
|
|
<span class="Keyword">return</span> <span class="LibraryFunction">eval</span>(coffee.<span class="LibraryFunction">compile</span>(code));
|
|
}));
|
|
}
|
|
<span class="Keyword">return</span> _a;
|
|
});
|
|
</pre><br class='clear' /></div>
|
|
|
|
<h2>
|
|
<span id="scripts" class="bookmark"></span>
|
|
"text/coffeescript" Script Tags
|
|
</h2>
|
|
|
|
<p>
|
|
While it's not recommended for serious use, CoffeeScripts may be included
|
|
directly within the browser using <tt><script type="text/coffeescript"></tt>
|
|
tags. The source includes a compressed and minified version of the compiler
|
|
(<a href="extras/coffee-script.js">Download current version here, 43k when gzipped</a>)
|
|
as <tt>extras/coffee-script.js</tt>. Include this file on a page with
|
|
inline CoffeeScript tags, and it will compile and evaluate them in order.
|
|
</p>
|
|
|
|
<p>
|
|
In fact, the little bit of glue script that runs "Try CoffeeScript" above,
|
|
as well as jQuery for the menu, is implemented in just this way.
|
|
View source and look at the bottom of the page to see the example.
|
|
Including the script also gives you access to <tt>CoffeeScript.compile()</tt>
|
|
so you can pop open Firebug and try compiling some strings.
|
|
</p>
|
|
|
|
<p>
|
|
The usual caveats about CoffeeScript apply — your inline scripts will
|
|
run within a closure wrapper, so if you want to expose global variables or
|
|
functions, attach them to the <tt>window</tt> object.
|
|
</p>
|
|
|
|
<h2>
|
|
<span id="resources" class="bookmark"></span>
|
|
Resources
|
|
</h2>
|
|
|
|
<ul>
|
|
<li>
|
|
<a href="http://github.com/jashkenas/coffee-script/">Source Code</a><br />
|
|
Use <tt>bin/coffee</tt> to test your changes,<br />
|
|
<tt>bin/cake test</tt> to run the test suite,<br />
|
|
<tt>bin/cake build</tt> to rebuild the CoffeeScript compiler, and <br />
|
|
<tt>bin/cake build:parser</tt> to regenerate the Jison parser if you're
|
|
working on the grammar. <br /><br />
|
|
<tt>git checkout lib && bin/cake build:full</tt> is a good command to run when you're working
|
|
on the core language. It'll refresh the lib directory
|
|
(in case you broke something), build your altered compiler, use that to
|
|
rebuild itself (a good sanity test) and then run all of the tests. If
|
|
they pass, there's a good chance you've made a successful change.
|
|
</li>
|
|
<li>
|
|
<a href="http://github.com/jashkenas/coffee-script/issues">CoffeeScript Issues</a><br />
|
|
Bugs reports, feature requests, and general discussion all belong here.
|
|
</li>
|
|
<li>
|
|
If you'd like to chat, stop by <tt>#coffeescript</tt> on Freenode in the
|
|
IRC client of your choice, or on
|
|
<a href="http://webchat.freenode.net/">webchat.freenode.net</a>.
|
|
</li>
|
|
<li>
|
|
<b>defunkt</b>'s <a href="http://github.com/defunkt/coffee-mode">CoffeeScript Major Mode</a>
|
|
— a Emacs major mode that provides syntax highlighting, indentation
|
|
support, and some bonus commands.
|
|
</li>
|
|
<li>
|
|
<b>jashkenas</b>'s <a href="http://github.com/jashkenas/coffee-script-tmbundle">CoffeeScript TextMate Bundle</a>
|
|
— which provides syntax highlighting, snippet expansion, and the
|
|
ability to run bits of CoffeeScript from within TextMate itself.
|
|
</li>
|
|
<li>
|
|
<b>kchmck</b>'s <a href="http://github.com/kchmck/vim-coffee-script">Vim CoffeeScript</a>
|
|
— which adds Vim syntax highlighting and indentation support.
|
|
</li>
|
|
<li>
|
|
<b>mattly</b>'s <a href="http://github.com/mattly/rack-coffee">rack-coffee</a>
|
|
— a small Rack middleware for serving CoffeeScript files as
|
|
compiled JavaScript on the fly.
|
|
</li>
|
|
<li>
|
|
<b>jnicklas</b>'s <a href="http://github.com/jnicklas/bistro_car">BistroCar</a>
|
|
— a plugin that serves and bundles CoffeeScript from within your
|
|
Rails application.
|
|
</li>
|
|
</ul>
|
|
|
|
<h2>
|
|
<span id="webchat" class="bookmark"></span>
|
|
Web Chat (IRC)
|
|
</h2>
|
|
|
|
<p>
|
|
Quick help and advice can usually be found in the CoffeeScript IRC room.
|
|
Join <tt>#coffeescript</tt> on <tt>irc.freenode.net</tt>, or click the
|
|
button below to open a webchat session on this page.
|
|
</p>
|
|
|
|
<p>
|
|
<button id="open_webchat">click to open #coffeescript</button>
|
|
</p>
|
|
|
|
<h2>
|
|
<span id="change_log" class="bookmark"></span>
|
|
Change Log
|
|
</h2>
|
|
|
|
<p>
|
|
<b class="header" style="margin-top: 20px;">0.6.0</b>
|
|
Trailing commas are now allowed, a-la Python. Static
|
|
properties may be assigned directly within class definitions,
|
|
using <tt>@property</tt> notation.
|
|
</p>
|
|
|
|
<p>
|
|
<b class="header" style="margin-top: 20px;">0.5.6</b>
|
|
Interpolation can now be used within regular expressions and heredocs, as well as
|
|
strings. Added the <tt><-</tt> bind operator.
|
|
Allowing assignment to half-expressions instead of special <tt>||=</tt>-style
|
|
operators. The arguments object is no longer automatically converted into
|
|
an array. After requiring <tt>coffee-script</tt>, Node.js can now directly
|
|
load <tt>.coffee</tt> files, thanks to <b>registerExtension</b>. Multiple
|
|
splats can now be used in function calls, arrays, and pattern matching.
|
|
</p>
|
|
|
|
<p>
|
|
<b class="header" style="margin-top: 20px;">0.5.5</b>
|
|
String interpolation, contributed by
|
|
<a href="http://github.com/StanAngeloff">Stan Angeloff</a>.
|
|
Since <tt>--run</tt> has been the default since <b>0.5.3</b>, updating
|
|
<tt>--stdio</tt> and <tt>--eval</tt> to run by default, pass <tt>--compile</tt>
|
|
as well if you'd like to print the result.
|
|
</p>
|
|
|
|
<p>
|
|
<b class="header" style="margin-top: 20px;">0.5.4</b>
|
|
Bugfix that corrects the Node.js global constants <tt>__filename</tt> and
|
|
<tt>__dirname</tt>. Tweaks for more flexible parsing of nested function
|
|
literals and improperly-indented comments. Updates for the latest Node.js API.
|
|
</p>
|
|
|
|
<p>
|
|
<b class="header" style="margin-top: 20px;">0.5.3</b>
|
|
CoffeeScript now has a syntax for defining classes. Many of the core
|
|
components (Nodes, Lexer, Rewriter, Scope, Optparse) are using them.
|
|
Cakefiles can use <tt>optparse.coffee</tt> to define options for tasks.
|
|
<tt>--run</tt> is now the default flag for the <tt>coffee</tt> command,
|
|
use <tt>--compile</tt> to save JavaScripts. Bugfix for an ambiguity between
|
|
RegExp literals and chained divisions.
|
|
</p>
|
|
|
|
<p>
|
|
<b class="header" style="margin-top: 20px;">0.5.2</b>
|
|
Added a compressed version of the compiler for inclusion in web pages as
|
|
<br /><tt>extras/coffee-script.js</tt>. It'll automatically run any script tags
|
|
with type <tt>text/coffeescript</tt> for you. Added a <tt>--stdio</tt> option
|
|
to the <tt>coffee</tt> command, for piped-in compiles.
|
|
</p>
|
|
|
|
|
|
<p>
|
|
<b class="header" style="margin-top: 20px;">0.5.1</b>
|
|
Improvements to null soaking with the existential operator, including
|
|
soaks on indexed properties. Added conditions to <tt>while</tt> loops,
|
|
so you can use them as filters with <tt>when</tt>, in the same manner as
|
|
comprehensions.
|
|
</p>
|
|
|
|
<p>
|
|
<b class="header" style="margin-top: 20px;">0.5.0</b>
|
|
CoffeeScript 0.5.0 is a major release, While there are no language changes,
|
|
the Ruby compiler has been removed in favor of a self-hosting
|
|
compiler written in pure CoffeeScript.
|
|
</p>
|
|
|
|
<p>
|
|
<b class="header" style="margin-top: 20px;">0.3.2</b>
|
|
<tt>@property</tt> is now a shorthand for <tt>this.property</tt>.<br />
|
|
Switched the default JavaScript engine from Narwhal to Node.js. Pass
|
|
the <tt>--narwhal</tt> flag if you'd like to continue using it.
|
|
</p>
|
|
|
|
<p>
|
|
<b class="header" style="margin-top: 20px;">0.3.0</b>
|
|
CoffeeScript 0.3 includes major syntax changes:
|
|
<br />
|
|
The function symbol was changed to
|
|
<tt>-></tt>, and the bound function symbol is now <tt>=></tt>.
|
|
<br />
|
|
Parameter lists in function definitions must now be wrapped in parentheses.
|
|
<br />
|
|
Added property soaking, with the <tt>?.</tt> operator.
|
|
<br />
|
|
Made parentheses optional, when invoking functions with arguments.
|
|
<br />
|
|
Removed the obsolete block literal syntax.
|
|
</p>
|
|
|
|
<p>
|
|
<b class="header" style="margin-top: 20px;">0.2.6</b>
|
|
Added Python-style chained comparisons, the conditional existence
|
|
operator <tt>?=</tt>, and some examples from <i>Beautiful Code</i>.
|
|
Bugfixes relating to statement-to-expression conversion, arguments-to-array
|
|
conversion, and the TextMate syntax highlighter.
|
|
</p>
|
|
|
|
<p>
|
|
<b class="header" style="margin-top: 20px;">0.2.5</b>
|
|
The conditions in switch statements can now take multiple values at once —
|
|
If any of them are true, the case will run. Added the long arrow <tt>==></tt>,
|
|
which defines and immediately binds a function to <tt>this</tt>. While loops can
|
|
now be used as expressions, in the same way that comprehensions can. Splats
|
|
can be used within pattern matches to soak up the rest of an array.
|
|
</p>
|
|
|
|
<p>
|
|
<b class="header" style="margin-top: 20px;">0.2.4</b>
|
|
Added ECMAScript Harmony style destructuring assignment, for dealing with
|
|
extracting values from nested arrays and objects. Added indentation-sensitive
|
|
heredocs for nicely formatted strings or chunks of code.
|
|
</p>
|
|
|
|
<p>
|
|
<b class="header" style="margin-top: 20px;">0.2.3</b>
|
|
Axed the unsatisfactory <tt>ino</tt> keyword, replacing it with <tt>of</tt> for
|
|
object comprehensions. They now look like: <tt>for prop, value of object</tt>.
|
|
</p>
|
|
|
|
<p>
|
|
<b class="header" style="margin-top: 20px;">0.2.2</b>
|
|
When performing a comprehension over an object, use <tt>ino</tt>, instead
|
|
of <tt>in</tt>, which helps us generate smaller, more efficient code at
|
|
compile time.
|
|
<br />
|
|
Added <tt>::</tt> as a shorthand for saying <tt>.prototype.</tt>
|
|
<br />
|
|
The "splat" symbol has been changed from a prefix asterisk <tt>*</tt>, to
|
|
a postfix ellipsis <tt>...</tt>
|
|
<br />
|
|
Added JavaScript's <tt>in</tt> operator,
|
|
empty <tt>return</tt> statements, and empty <tt>while</tt> loops.
|
|
<br />
|
|
Constructor functions that start with capital letters now include a
|
|
safety check to make sure that the new instance of the object is returned.
|
|
<br />
|
|
The <tt>extends</tt> keyword now functions identically to <tt>goog.inherits</tt>
|
|
in Google's Closure Library.
|
|
</p>
|
|
|
|
<p>
|
|
<b class="header" style="margin-top: 20px;">0.2.1</b>
|
|
Arguments objects are now converted into real arrays when referenced.
|
|
</p>
|
|
|
|
<p>
|
|
<b class="header" style="margin-top: 20px;">0.2.0</b>
|
|
Major release. Significant whitespace. Better statement-to-expression
|
|
conversion. Splats. Splice literals. Object comprehensions. Blocks.
|
|
The existential operator. Many thanks to all the folks who posted issues,
|
|
with special thanks to
|
|
<a href="http://github.com/kamatsu">Liam O'Connor-Davis</a> for whitespace
|
|
and expression help.
|
|
</p>
|
|
|
|
<p>
|
|
<b class="header" style="margin-top: 20px;">0.1.6</b>
|
|
Bugfix for running <tt>coffee --interactive</tt> and <tt>--run</tt>
|
|
from outside of the CoffeeScript directory. Bugfix for nested
|
|
function/if-statements.
|
|
</p>
|
|
|
|
<p>
|
|
<b class="header" style="margin-top: 20px;">0.1.5</b>
|
|
Array slice literals and array comprehensions can now both take Ruby-style
|
|
ranges to specify the start and end. JavaScript variable declaration is
|
|
now pushed up to the top of the scope, making all assignment statements into
|
|
expressions. You can use <tt>\</tt> to escape newlines.
|
|
The <tt>coffee-script</tt> command is now called <tt>coffee</tt>.
|
|
</p>
|
|
|
|
<p>
|
|
<b class="header" style="margin-top: 20px;">0.1.4</b>
|
|
The official CoffeeScript extension is now <tt>.coffee</tt> instead of
|
|
<tt>.cs</tt>, which properly belongs to
|
|
<a href="http://en.wikipedia.org/wiki/C_Sharp_(programming_language)">C#</a>.
|
|
Due to popular demand, you can now also use <tt>=</tt> to assign. Unlike
|
|
JavaScript, <tt>=</tt> can also be used within object literals, interchangeably
|
|
with <tt>:</tt>. Made a grammatical fix for chained function calls
|
|
like <tt>func(1)(2)(3)(4)</tt>. Inheritance and super no longer use
|
|
<tt>__proto__</tt>, so they should be IE-compatible now.
|
|
</p>
|
|
|
|
<p>
|
|
<b class="header" style="margin-top: 20px;">0.1.3</b>
|
|
The <tt>coffee</tt> command now includes <tt>--interactive</tt>,
|
|
which launches an interactive CoffeeScript session, and <tt>--run</tt>,
|
|
which directly compiles and executes a script. Both options depend on a
|
|
working installation of Narwhal.
|
|
The <tt>aint</tt> keyword has been replaced by <tt>isnt</tt>, which goes
|
|
together a little smoother with <tt>is</tt>.
|
|
Quoted strings are now allowed as identifiers within object literals: eg.
|
|
<tt>{"5+5": 10}</tt>.
|
|
All assignment operators now use a colon: <tt>+:</tt>, <tt>-:</tt>,
|
|
<tt>*:</tt>, etc.
|
|
</p>
|
|
|
|
<p>
|
|
<b class="header" style="margin-top: 20px;">0.1.2</b>
|
|
Fixed a bug with calling <tt>super()</tt> through more than one level of
|
|
inheritance, with the re-addition of the <tt>extends</tt> keyword.
|
|
Added experimental <a href="http://narwhaljs.org/">Narwhal</a>
|
|
support (as a Tusk package), contributed by
|
|
<a href="http://tlrobinson.net/">Tom Robinson</a>, including
|
|
<b>bin/cs</b> as a CoffeeScript REPL and interpreter.
|
|
New <tt>--no-wrap</tt> option to suppress the safety function
|
|
wrapper.
|
|
</p>
|
|
|
|
<p>
|
|
<b class="header" style="margin-top: 20px;">0.1.1</b>
|
|
Added <tt>instanceof</tt> and <tt>typeof</tt> as operators.
|
|
</p>
|
|
|
|
<p>
|
|
<b class="header" style="margin-top: 20px;">0.1.0</b>
|
|
Initial CoffeeScript release.
|
|
</p>
|
|
|
|
</div>
|
|
|
|
<script type="text/coffeescript">
|
|
|
|
# Set up the compilation function, to run when you stop typing.
|
|
compile_source: ->
|
|
source: $('#repl_source').val()
|
|
window.compiled_js: ''
|
|
try
|
|
window.compiled_js: CoffeeScript.compile source, {no_wrap: true}
|
|
$('#repl_results').text window.compiled_js
|
|
$('#error').hide();
|
|
catch error
|
|
$('#error').text(error.message).show();
|
|
|
|
# Listen for keypresses and recompile.
|
|
$('#repl_source').keyup -> compile_source()
|
|
|
|
# Eval the compiled js.
|
|
$('button.run').click ->
|
|
try
|
|
eval window.compiled_js
|
|
catch error then alert error
|
|
|
|
current_nav: null
|
|
|
|
# Helper to hide the menus.
|
|
close_menus: ->
|
|
if current_nav
|
|
current_nav.removeClass 'active'
|
|
document.body.className: 'minimized'
|
|
current_nav: null
|
|
|
|
# Bind navigation buttons to open the menus.
|
|
$('.navigation').click (e) ->
|
|
return if e.target.tagName.toLowerCase() is 'a'
|
|
if this isnt (current_nav and current_nav[0])
|
|
close_menus();
|
|
current_nav: $(this)
|
|
current_nav.addClass 'active'
|
|
false
|
|
|
|
$(document.body).click -> close_menus()
|
|
|
|
$('.navigation .full_screen').click ->
|
|
document.body.className: 'full_screen'
|
|
|
|
$('.navigation .minimize').click ->
|
|
document.body.className: 'minimized'
|
|
|
|
$('#open_webchat').click ->
|
|
$(this).replaceWith $('<iframe src="http://webchat.freenode.net/?channels=coffeescript" width="625" height="400"></iframe>')
|
|
|
|
compile_source()
|
|
|
|
</script>
|
|
|
|
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js"></script>
|
|
<script src="extras/coffee-script.js"></script>
|
|
|
|
</body>
|
|
</html>
|