2242 lines
132 KiB
HTML
2242 lines
132 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="#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">If, Else, Unless, 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, Until, and Loop</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">The Switch Statement</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="#heredocs">Multiline Strings, Heredocs, and Block Comments</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" rows="100">alert "Hello CoffeeScript!"</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 pretty-printed and quite readable.
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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/0.9.4">0.9.4</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 <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
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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: Math.sqrt
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square: 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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<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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cubes <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> _i, _len, _ref, _result, cubes, list, math, num, number, opposite, 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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number <span class="Keyword">=</span> <span class="Number">42</span>;
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opposite <span class="Keyword">=</span> <span class="BuiltInConstant">true</span>;
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<span class="Keyword">if</span> (opposite) {
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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="FunctionName">square</span> = <span class="Storage">function</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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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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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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<span class="FunctionName">cube</span>: <span class="Storage">function</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="FunctionName">race</span> = <span class="Storage">function</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>);
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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="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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cubes <span class="Keyword">=</span> (<span class="Storage">function</span>() {
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_result <span class="Keyword">=</span> []; _ref <span class="Keyword">=</span> list;
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<span class="Keyword">for</span> (_i <span class="Keyword">=</span> <span class="Number">0</span>, _len <span class="Keyword">=</span> _ref.<span class="LibraryConstant">length</span>; _i <span class="Keyword"><</span> _len; _i<span class="Keyword">++</span>) {
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num <span class="Keyword">=</span> _ref[_i];
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_result.<span class="LibraryFunction">push</span>(math.cube(num));
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}
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<span class="Keyword">return</span> _result;
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})();
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</pre><button onclick='javascript: var _i, _len, _ref, _result, cubes, list, math, num, number, opposite, race, square;
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var __slice = Array.prototype.slice;
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number = 42;
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opposite = true;
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if (opposite) {
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number = -42;
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}
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square = function(x) {
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return x * x;
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};
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list = [1, 2, 3, 4, 5];
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math = {
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root: Math.sqrt,
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square: square,
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cube: function(x) {
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return x * square(x);
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}
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};
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race = function(winner) {
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var runners;
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runners = __slice.call(arguments, 1);
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return print(winner, runners);
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};
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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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cubes = (function() {
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_result = []; _ref = list;
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for (_i = 0, _len = _ref.length; _i < _len; _i++) {
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num = _ref[_i];
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_result.push(math.cube(num));
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}
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return _result;
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})();;alert(cubes);'>run: cubes</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).
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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>0.1.102</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/0.9.4">0.9.4</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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Alternatively, if you already have the
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<a href="http://npmjs.org/">Node Package Manager</a> installed,
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you can use that to grab the latest CoffeeScript:
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</p>
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<pre>
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sudo npm install coffee-script</pre>
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<p>
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Both of these provide 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 <br /> <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>-r, --require</code></td>
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<td>
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Load a library before compiling or executing your script. Can be used
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to hook in to the compiler (to add Growl notifications, for example).
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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>
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This reference is structured so that it can be read from top to bottom,
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if you like. Later sections use ideas and syntax previously introduced.
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Familiarity with JavaScript is assumed.
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In all of the following examples, the source CoffeeScript is provided on
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the left, and the direct compilation into JavaScript is on the right.
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</i>
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</p>
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<p>
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<i>
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Many of the examples can be run (where it makes sense) by pressing the "run"
|
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button towards the bottom right. You can also paste examples into
|
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"Try CoffeeScript" in the toolbar, and play with them from there.
|
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</i>
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<p>
|
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<span id="whitespace" class="bookmark"></span>
|
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<b class="header">Significant Whitespace</b>
|
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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>. Implicit parentheses wrap forwards
|
|
to the end of the line, or block expression.
|
|
</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 ... seen most commonly
|
|
in jQuery-chaining style JavaScript.
|
|
</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>
|
|
</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;
|
|
<span class="FunctionName">square</span> = <span class="Storage">function</span>(<span class="FunctionArgument">x</span>) {
|
|
<span class="Keyword">return</span> x <span class="Keyword">*</span> x;
|
|
};
|
|
<span class="FunctionName">cube</span> = <span class="Storage">function</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(x) {
|
|
return x * x;
|
|
};
|
|
cube = function(x) {
|
|
return square(x) * x;
|
|
};;alert(cube(5));'>run: cube(5)</button><br class='clear' /></div>
|
|
|
|
<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 property on a separate line, the commas are
|
|
optional. Implicit objects may be created with indentation instead of
|
|
brackets, winding up looking quite similar to YAML.
|
|
</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>]
|
|
|
|
singers <span class="Keyword">=</span> {Jagger: <span class="String"><span class="String">"</span>Rock<span class="String">"</span></span>, Elvis: <span class="String"><span class="String">"</span>Roll<span class="String">"</span></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>
|
|
]
|
|
|
|
kids <span class="Keyword">=</span>
|
|
brother:
|
|
name: <span class="String"><span class="String">"</span>Max<span class="String">"</span></span>
|
|
age: <span class="Number">11</span>
|
|
sister:
|
|
name: <span class="String"><span class="String">"</span>Ida<span class="String">"</span></span>
|
|
age: <span class="Number">9</span>
|
|
</pre><pre class="idle"><span class="Storage">var</span> kids, matrix, singers, 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>];
|
|
singers <span class="Keyword">=</span> {
|
|
Jagger: <span class="String"><span class="String">"</span>Rock<span class="String">"</span></span>,
|
|
Elvis: <span class="String"><span class="String">"</span>Roll<span class="String">"</span></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>];
|
|
kids <span class="Keyword">=</span> {
|
|
brother: {
|
|
name: <span class="String"><span class="String">"</span>Max<span class="String">"</span></span>,
|
|
age: <span class="Number">11</span>
|
|
},
|
|
sister: {
|
|
name: <span class="String"><span class="String">"</span>Ida<span class="String">"</span></span>,
|
|
age: <span class="Number">9</span>
|
|
}
|
|
};
|
|
</pre><button onclick='javascript: var kids, matrix, singers, song;
|
|
song = ["do", "re", "mi", "fa", "so"];
|
|
singers = {
|
|
Jagger: "Rock",
|
|
Elvis: "Roll"
|
|
};
|
|
matrix = [1, 0, 1, 0, 0, 1, 1, 1, 0];
|
|
kids = {
|
|
brother: {
|
|
name: "Max",
|
|
age: 11
|
|
},
|
|
sister: {
|
|
name: "Ida",
|
|
age: 9
|
|
}
|
|
};;alert(song.join(","));'>run: song.join(",")</button><br class='clear' /></div>
|
|
<p>
|
|
In JavaScript, you can't use reserved words, like <tt>class</tt>, as properties
|
|
of an object, without quoting them as strings. CoffeeScript notices and quotes
|
|
them for you, so you don't have to worry about it (say, when using jQuery).
|
|
</p>
|
|
<div class='code'><pre class="idle">$(<span class="String"><span class="String">'</span>.account<span class="String">'</span></span>).css class: <span class="String"><span class="String">'</span>active<span class="String">'</span></span>
|
|
</pre><pre class="idle"><span class="Keyword">$</span>(<span class="String"><span class="String">'</span>.account<span class="String">'</span></span>).css({
|
|
<span class="String"><span class="String">"</span>class<span class="String">"</span></span>: <span class="String"><span class="String">'</span>active<span class="String">'</span></span>
|
|
});
|
|
</pre><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">outer <span class="Keyword">=</span> <span class="Number">1</span>
|
|
<span class="FunctionName">changeNumbers </span><span class="Keyword">=</span> <span class="Storage">-></span>
|
|
inner <span class="Keyword">=</span> <span class="Keyword">-</span><span class="Number">1</span>
|
|
outer <span class="Keyword">=</span> <span class="Number">10</span>
|
|
inner <span class="Keyword">=</span> changeNumbers()
|
|
</pre><pre class="idle"><span class="Storage">var</span> changeNumbers, inner, outer;
|
|
outer <span class="Keyword">=</span> <span class="Number">1</span>;
|
|
<span class="FunctionName">changeNumbers</span> = <span class="Storage">function</span>() {
|
|
<span class="Storage">var</span> inner;
|
|
inner <span class="Keyword">=</span> <span class="Keyword">-</span><span class="Number">1</span>;
|
|
<span class="Keyword">return</span> (outer <span class="Keyword">=</span> <span class="Number">10</span>);
|
|
};
|
|
inner <span class="Keyword">=</span> changeNumbers();
|
|
</pre><button onclick='javascript: var changeNumbers, inner, outer;
|
|
outer = 1;
|
|
changeNumbers = function() {
|
|
var inner;
|
|
inner = -1;
|
|
return (outer = 10);
|
|
};
|
|
inner = changeNumbers();;alert(inner);'>run: inner</button><br class='clear' /></div>
|
|
<p>
|
|
Notice how all of the variable declarations have been pushed up to
|
|
the top of the closest scope, the first time they appear.
|
|
<b>outer</b> is not redeclared within the inner function, because it's
|
|
already in scope; <b>inner</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> (covered 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">If, Else, Unless, 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 can compile <b>if</b> statements into JavaScript expressions,
|
|
using the ternary operator when possible, and closure wrapping otherwise. There
|
|
is no explicit ternary statement in CoffeeScript — you simply use
|
|
a regular <b>if</b> statement inline.
|
|
</p>
|
|
<div class='code'><pre class="idle">mood <span class="Keyword">=</span> greatlyImproved <span class="Keyword">if</span> singing
|
|
|
|
<span class="Keyword">if</span> happy <span class="Keyword">and</span> knowsIt
|
|
clapsHands()
|
|
chaChaCha()
|
|
<span class="Keyword">else</span>
|
|
showIt()
|
|
|
|
date <span class="Keyword">=</span> <span class="Keyword">if</span> friday <span class="Keyword">then</span> sue <span class="Keyword">else</span> jill
|
|
|
|
options or<span class="Keyword">=</span> defaults
|
|
</pre><pre class="idle"><span class="Storage">var</span> date, mood, options;
|
|
<span class="Keyword">if</span> (singing) {
|
|
mood <span class="Keyword">=</span> greatlyImproved;
|
|
}
|
|
<span class="Keyword">if</span> (happy <span class="Keyword">&</span><span class="Keyword">&</span> knowsIt) {
|
|
clapsHands();
|
|
chaChaCha();
|
|
} <span class="Keyword">else</span> {
|
|
showIt();
|
|
}
|
|
date <span class="Keyword">=</span> friday ? sue : jill;
|
|
options <span class="Keyword">||</span> (options <span class="Keyword">=</span> defaults);
|
|
</pre><br class='clear' /></div>
|
|
|
|
<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>
|
|
<p>
|
|
You can use <tt>in</tt> to test for array presence, and <tt>of</tt> to
|
|
test for JavaScript object-key presence.
|
|
</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> SpinalTap
|
|
|
|
letTheWildRumpusBegin() <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> limit <span class="Keyword">then</span> accelerate()
|
|
|
|
winner <span class="Keyword">=</span> <span class="BuiltInConstant">yes</span> <span class="Keyword">if</span> pick <span class="Keyword">in</span> [<span class="Number">47</span>, <span class="Number">92</span>, <span class="Number">13</span>]
|
|
|
|
print inspect <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, winner;
|
|
<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> SpinalTap) {
|
|
volume <span class="Keyword">=</span> <span class="Number">10</span>;
|
|
}
|
|
<span class="Keyword">if</span> (answer <span class="Keyword">!</span><span class="Keyword">==</span> <span class="BuiltInConstant">false</span>) {
|
|
letTheWildRumpusBegin();
|
|
}
|
|
<span class="Keyword">if</span> (car.speed <span class="Keyword"><</span> limit) {
|
|
accelerate();
|
|
}
|
|
<span class="Keyword">if</span> ((<span class="Number">47</span> <span class="Keyword">===</span> pick <span class="Keyword">||</span> <span class="Number">92</span> <span class="Keyword">===</span> pick <span class="Keyword">||</span> <span class="Number">13</span> <span class="Keyword">===</span> pick)) {
|
|
winner <span class="Keyword">=</span> <span class="BuiltInConstant">true</span>;
|
|
}
|
|
<span class="LibraryFunction">print</span>(inspect(<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> rest <span class="Keyword">=</span> <span class="String"><span class="String">"</span>unknown<span class="String">"</span></span>
|
|
|
|
<span class="FunctionName">awardMedals </span><span class="Keyword">=</span> <span class="FunctionArgument">(</span><span class="FunctionArgument">first, second, others...</span><span class="FunctionArgument">)</span> <span class="Storage">-></span>
|
|
gold <span class="Keyword">=</span> first
|
|
silver <span class="Keyword">=</span> second
|
|
rest <span class="Keyword">=</span> others
|
|
|
|
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>
|
|
]
|
|
|
|
awardMedals 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> rest
|
|
</pre><pre class="idle"><span class="Storage">var</span> awardMedals, contenders, gold, rest, silver;
|
|
<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> (rest <span class="Keyword">=</span> <span class="String"><span class="String">"</span>unknown<span class="String">"</span></span>));
|
|
<span class="FunctionName">awardMedals</span> = <span class="Storage">function</span>(<span class="FunctionArgument">first, second</span>) {
|
|
<span class="Storage">var</span> others;
|
|
others <span class="Keyword">=</span> __slice.<span class="LibraryFunction">call</span>(arguments, <span class="Number">2</span>);
|
|
gold <span class="Keyword">=</span> first;
|
|
silver <span class="Keyword">=</span> second;
|
|
<span class="Keyword">return</span> (rest <span class="Keyword">=</span> others);
|
|
};
|
|
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>];
|
|
awardMedals.<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> rest);
|
|
</pre><button onclick='javascript: var awardMedals, contenders, gold, rest, silver;
|
|
var __slice = Array.prototype.slice;
|
|
gold = (silver = (rest = "unknown"));
|
|
awardMedals = function(first, second) {
|
|
var others;
|
|
others = __slice.call(arguments, 2);
|
|
gold = first;
|
|
silver = second;
|
|
return (rest = others);
|
|
};
|
|
contenders = ["Michael Phelps", "Liu Xiang", "Yao Ming", "Allyson Felix", "Shawn Johnson", "Roman Sebrle", "Guo Jingjing", "Tyson Gay", "Asafa Powell", "Usain Bolt"];
|
|
awardMedals.apply(this, contenders);
|
|
alert("Gold: " + gold);
|
|
alert("Silver: " + silver);
|
|
alert("The Field: " + rest);;'>run</button><br class='clear' /></div>
|
|
|
|
<p>
|
|
<span id="while" class="bookmark"></span>
|
|
<b class="header">While, Until, and Loop</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>.studyingEconomics
|
|
buy() <span class="Keyword">while</span> supply <span class="Keyword">></span> demand
|
|
sell() <span class="Keyword">until</span> supply <span class="Keyword">></span> demand
|
|
|
|
<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> _result, lyrics, num;
|
|
<span class="Keyword">if</span> (<span class="Variable">this</span>.studyingEconomics) {
|
|
<span class="Keyword">while</span> (supply <span class="Keyword">></span> demand) {
|
|
buy();
|
|
}
|
|
<span class="Keyword">while</span> (<span class="Keyword">!</span>(supply <span class="Keyword">></span> demand)) {
|
|
sell();
|
|
}
|
|
}
|
|
num <span class="Keyword">=</span> <span class="Number">6</span>;
|
|
lyrics <span class="Keyword">=</span> (<span class="Storage">function</span>() {
|
|
_result <span class="Keyword">=</span> [];
|
|
<span class="Keyword">while</span> (num <span class="Keyword">-</span><span class="Keyword">=</span> <span class="Number">1</span>) {
|
|
_result.<span class="LibraryFunction">push</span>(num <span class="Keyword">+</span> <span class="String"><span class="String">"</span> little monkeys, jumping on the bed. One fell out and bumped his head.<span class="String">"</span></span>);
|
|
}
|
|
<span class="Keyword">return</span> _result;
|
|
})();
|
|
</pre><button onclick='javascript: var _result, lyrics, num;
|
|
if (this.studyingEconomics) {
|
|
while (supply > demand) {
|
|
buy();
|
|
}
|
|
while (!(supply > demand)) {
|
|
sell();
|
|
}
|
|
}
|
|
num = 6;
|
|
lyrics = (function() {
|
|
_result = [];
|
|
while (num -= 1) {
|
|
_result.push(num + " little monkeys, jumping on the bed. One fell out and bumped his head.");
|
|
}
|
|
return _result;
|
|
})();;alert(lyrics.join("\n"));'>run: lyrics.join("\n")</button><br class='clear' /></div>
|
|
<p>
|
|
For readability, the <b>until</b> keyword is equivalent to <tt>while not</tt>,
|
|
and the <b>loop</b> keyword is equivalent to <tt>while true</tt>.
|
|
Other JavaScript loops, such as <b>for</b> loops and <b>do-while</b> loops
|
|
can be mimicked by variations on <b>loop</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> _i, _j, _len, _len2, _ref, _ref2, _result, food, lunch, roid, roid2;
|
|
lunch <span class="Keyword">=</span> (<span class="Storage">function</span>() {
|
|
_result <span class="Keyword">=</span> []; _ref <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> (_i <span class="Keyword">=</span> <span class="Number">0</span>, _len <span class="Keyword">=</span> _ref.<span class="LibraryConstant">length</span>; _i <span class="Keyword"><</span> _len; _i<span class="Keyword">++</span>) {
|
|
food <span class="Keyword">=</span> _ref[_i];
|
|
_result.<span class="LibraryFunction">push</span>(eat(food));
|
|
}
|
|
<span class="Keyword">return</span> _result;
|
|
})();
|
|
_ref <span class="Keyword">=</span> asteroids;
|
|
<span class="Keyword">for</span> (_i <span class="Keyword">=</span> <span class="Number">0</span>, _len <span class="Keyword">=</span> _ref.<span class="LibraryConstant">length</span>; _i <span class="Keyword"><</span> _len; _i<span class="Keyword">++</span>) {
|
|
roid <span class="Keyword">=</span> _ref[_i];
|
|
_ref2 <span class="Keyword">=</span> asteroids;
|
|
<span class="Keyword">for</span> (_j <span class="Keyword">=</span> <span class="Number">0</span>, _len2 <span class="Keyword">=</span> _ref2.<span class="LibraryConstant">length</span>; _j <span class="Keyword"><</span> _len2; _j<span class="Keyword">++</span>) {
|
|
roid2 <span class="Keyword">=</span> _ref2[_j];
|
|
<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.
|
|
</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">deliverEggs </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 <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">eggCarton</span> dozen
|
|
</pre><pre class="idle"><span class="Storage">var</span> _result, countdown, deliverEggs, num;
|
|
countdown <span class="Keyword">=</span> (<span class="Storage">function</span>() {
|
|
_result <span class="Keyword">=</span> [];
|
|
<span class="Keyword">for</span> (num <span class="Keyword">=</span> <span class="Number">10</span>; num <span class="Keyword">>=</span> <span class="Number">1</span>; num<span class="Keyword">--</span>) {
|
|
_result.<span class="LibraryFunction">push</span>(num);
|
|
}
|
|
<span class="Keyword">return</span> _result;
|
|
})();
|
|
<span class="FunctionName">deliverEggs</span> = <span class="Storage">function</span>() {
|
|
<span class="Storage">var</span> _ref, _result2, dozen, i;
|
|
_result2 <span class="Keyword">=</span> []; _ref <span class="Keyword">=</span> eggs.<span class="LibraryConstant">length</span>;
|
|
<span class="Keyword">for</span> (i <span class="Keyword">=</span> <span class="Number">0</span>; (<span class="Number">0</span> <span class="Keyword"><=</span> _ref ? i <span class="Keyword"><</span> _ref : i <span class="Keyword">></span> _ref); i <span class="Keyword">+</span><span class="Keyword">=</span> <span class="Number">12</span>) {
|
|
_result2.<span class="LibraryFunction">push</span>((<span class="Storage">function</span>() {
|
|
dozen <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">eggCarton</span>(dozen));
|
|
})());
|
|
}
|
|
<span class="Keyword">return</span> _result2;
|
|
};
|
|
</pre><button onclick='javascript: var _result, countdown, deliverEggs, num;
|
|
countdown = (function() {
|
|
_result = [];
|
|
for (num = 10; num >= 1; num--) {
|
|
_result.push(num);
|
|
}
|
|
return _result;
|
|
})();
|
|
deliverEggs = function() {
|
|
var _ref, _result2, dozen, i;
|
|
_result2 = []; _ref = eggs.length;
|
|
for (i = 0; (0 <= _ref ? i < _ref : i > _ref); i += 12) {
|
|
_result2.push((function() {
|
|
dozen = eggs.slice(i, i + 12);
|
|
return deliver(new eggCarton(dozen));
|
|
})());
|
|
}
|
|
return _result2;
|
|
};;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">yearsOld <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="Keyword">for</span> child, age <span class="Keyword">of</span> yearsOld
|
|
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> _ref, _result, age, ages, child, yearsOld;
|
|
<span class="Storage">var</span> __hasProp <span class="Keyword">=</span> <span class="LibraryClassType">Object</span>.<span class="LibraryConstant">prototype</span>.hasOwnProperty;
|
|
yearsOld <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>() {
|
|
_result <span class="Keyword">=</span> []; _ref <span class="Keyword">=</span> yearsOld;
|
|
<span class="Keyword">for</span> (child <span class="Keyword">in</span> _ref) {
|
|
<span class="Keyword">if</span> (<span class="Keyword">!</span>__hasProp.<span class="LibraryFunction">call</span>(_ref, child)) <span class="Keyword">continue</span>;
|
|
age <span class="Keyword">=</span> _ref[child];
|
|
_result.<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> _result;
|
|
})();
|
|
</pre><button onclick='javascript: var _ref, _result, age, ages, child, yearsOld;
|
|
var __hasProp = Object.prototype.hasOwnProperty;
|
|
yearsOld = {
|
|
max: 10,
|
|
ida: 9,
|
|
tim: 11
|
|
};
|
|
ages = (function() {
|
|
_result = []; _ref = yearsOld;
|
|
for (child in _ref) {
|
|
if (!__hasProp.call(_ref, child)) continue;
|
|
age = _ref[child];
|
|
_result.push(child + " is " + age);
|
|
}
|
|
return _result;
|
|
})();;alert(ages.join(", "));'>run: ages.join(", ")</button><br class='clear' /></div>
|
|
<p>
|
|
By default, object comprehensions are safe, and use a <tt>hasOwnProperty</tt>
|
|
check to make sure that you're dealing with properties on the current
|
|
object. If you'd like the regular JavaScript <br /><tt>for (key in obj) ...</tt>
|
|
loop, for speed or for another reason, you can use <br />
|
|
<tt>for all key, value of object</tt> in CoffeeScript.
|
|
</p>
|
|
|
|
<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>]
|
|
|
|
threeToSix <span class="Keyword">=</span> numbers[<span class="Number">3</span>..<span class="Number">6</span>]
|
|
|
|
copy <span class="Keyword">=</span> numbers[<span class="Number">0</span>...numbers.length]
|
|
|
|
</pre><pre class="idle"><span class="Storage">var</span> copy, numbers, threeToSix;
|
|
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>];
|
|
threeToSix <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>);
|
|
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 copy, numbers, threeToSix;
|
|
numbers = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
|
|
threeToSix = numbers.slice(3, 6 + 1);
|
|
copy = numbers.slice(0, numbers.length);;alert(copy);'>run: 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.excellentWork
|
|
<span class="String"><span class="String">"</span>A+<span class="String">"</span></span>
|
|
<span class="Keyword">else</span> <span class="Keyword">if</span> student.okayStuff
|
|
<span class="Keyword">if</span> student.triedHard <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;
|
|
<span class="FunctionName">grade</span> = <span class="Storage">function</span>(<span class="FunctionArgument">student</span>) {
|
|
<span class="Keyword">return</span> student.excellentWork ? <span class="String"><span class="String">"</span>A+<span class="String">"</span></span> : (student.okayStuff ? (student.triedHard ? <span class="String"><span class="String">"</span>B<span class="String">"</span></span> : <span class="String"><span class="String">"</span>B-<span class="String">"</span></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(student) {
|
|
return student.excellentWork ? "A+" : (student.okayStuff ? (student.triedHard ? "B" : "B-") : "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> _ref, _result, globals, name;
|
|
<span class="Storage">var</span> __hasProp <span class="Keyword">=</span> <span class="LibraryClassType">Object</span>.<span class="LibraryConstant">prototype</span>.hasOwnProperty;
|
|
globals <span class="Keyword">=</span> (<span class="Storage">function</span>() {
|
|
_result <span class="Keyword">=</span> []; _ref <span class="Keyword">=</span> <span class="LibraryClassType">window</span>;
|
|
<span class="Keyword">for</span> (name <span class="Keyword">in</span> _ref) {
|
|
<span class="Keyword">if</span> (<span class="Keyword">!</span>__hasProp.<span class="LibraryFunction">call</span>(_ref, name)) <span class="Keyword">continue</span>;
|
|
_result.<span class="LibraryFunction">push</span>(name);
|
|
}
|
|
<span class="Keyword">return</span> _result;
|
|
})().<span class="LibraryFunction">slice</span>(<span class="Number">0</span>, <span class="Number">10</span>);
|
|
</pre><button onclick='javascript: var _ref, _result, globals, name;
|
|
var __hasProp = Object.prototype.hasOwnProperty;
|
|
globals = (function() {
|
|
_result = []; _ref = window;
|
|
for (name in _ref) {
|
|
if (!__hasProp.call(_ref, name)) continue;
|
|
_result.push(name);
|
|
}
|
|
return _result;
|
|
})().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;
|
|
}
|
|
})());
|
|
</pre><button onclick='javascript: alert((function() {
|
|
try {
|
|
return nonexistent / undefined;
|
|
} catch (error) {
|
|
return "And the error is ... " + error;
|
|
}
|
|
})());;'>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.drawWinner()<span class="Keyword">?</span>.address<span class="Keyword">?</span>.zipcode
|
|
</pre><pre class="idle"><span class="Storage">var</span> _ref, _ref2;
|
|
(<span class="Keyword">typeof</span> (_ref2 <span class="Keyword">=</span> ((_ref <span class="Keyword">=</span> lottery.drawWinner()))) <span class="Keyword">===</span> <span class="String"><span class="String">"</span>undefined<span class="String">"</span></span> <span class="Keyword">||</span> _ref2 <span class="Keyword">===</span> <span class="BuiltInConstant">null</span>) ? undefined : _ref2.address <span class="Keyword">==</span> <span class="BuiltInConstant">null</span> ? undefined : _ref2.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">constructor</span><span class="Keyword">:</span> (<span class="Variable">@name</span>) <span class="Storage">-></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">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">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>;
|
|
<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;
|
|
<span class="Keyword">if</span> (<span class="Keyword">typeof</span> parent.extended <span class="Keyword">===</span> <span class="String"><span class="String">"</span>function<span class="String">"</span></span>) parent.extended(child);
|
|
child.__super__ <span class="Keyword">=</span> parent.<span class="LibraryConstant">prototype</span>;
|
|
};
|
|
<span class="FunctionName">Animal</span> = <span class="Storage">function</span>(<span class="FunctionArgument">_arg</span>) {
|
|
<span class="Variable">this</span>.<span class="LibraryConstant">name</span> <span class="Keyword">=</span> _arg;
|
|
<span class="Keyword">return</span> <span class="Variable">this</span>;
|
|
};
|
|
<span class="LibraryClassType">Animal</span>.<span class="LibraryConstant">prototype</span>.<span class="FunctionName">move</span> = <span class="Storage">function</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>);
|
|
};
|
|
<span class="FunctionName">Snake</span> = <span class="Storage">function</span>() {
|
|
<span class="Keyword">return</span> Animal.<span class="LibraryFunction">apply</span>(<span class="Variable">this</span>, arguments);
|
|
};
|
|
__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="LibraryFunction">alert</span>(<span class="String"><span class="String">"</span>Slithering...<span class="String">"</span></span>);
|
|
<span class="Keyword">return</span> Snake.__super__.move.<span class="LibraryFunction">call</span>(<span class="Variable">this</span>, <span class="Number">5</span>);
|
|
};
|
|
<span class="FunctionName">Horse</span> = <span class="Storage">function</span>() {
|
|
<span class="Keyword">return</span> Animal.<span class="LibraryFunction">apply</span>(<span class="Variable">this</span>, arguments);
|
|
};
|
|
__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="LibraryFunction">alert</span>(<span class="String"><span class="String">"</span>Galloping...<span class="String">"</span></span>);
|
|
<span class="Keyword">return</span> Horse.__super__.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.prototype = new ctor();
|
|
child.prototype.constructor = child;
|
|
if (typeof parent.extended === "function") parent.extended(child);
|
|
child.__super__ = parent.prototype;
|
|
};
|
|
Animal = function(_arg) {
|
|
this.name = _arg;
|
|
return this;
|
|
};
|
|
Animal.prototype.move = function(meters) {
|
|
return alert(this.name + " moved " + meters + "m.");
|
|
};
|
|
Snake = function() {
|
|
return Animal.apply(this, arguments);
|
|
};
|
|
__extends(Snake, Animal);
|
|
Snake.prototype.move = function() {
|
|
alert("Slithering...");
|
|
return Snake.__super__.move.call(this, 5);
|
|
};
|
|
Horse = function() {
|
|
return Animal.apply(this, arguments);
|
|
};
|
|
__extends(Horse, Animal);
|
|
Horse.prototype.move = function() {
|
|
alert("Galloping...");
|
|
return Horse.__super__.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"> /_/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="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() {
|
|
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">theBait <span class="Keyword">=</span> <span class="Number">1000</span>
|
|
theSwitch <span class="Keyword">=</span> <span class="Number">0</span>
|
|
|
|
<span class="Keyword">[</span>theBait, theSwitch<span class="Keyword">] =</span> [theSwitch, theBait]
|
|
</pre><pre class="idle"><span class="Storage">var</span> _ref, theBait, theSwitch;
|
|
theBait <span class="Keyword">=</span> <span class="Number">1000</span>;
|
|
theSwitch <span class="Keyword">=</span> <span class="Number">0</span>;
|
|
_ref <span class="Keyword">=</span> [theSwitch, theBait];
|
|
theBait <span class="Keyword">=</span> _ref[<span class="Number">0</span>];
|
|
theSwitch <span class="Keyword">=</span> _ref[<span class="Number">1</span>];
|
|
</pre><button onclick='javascript: var _ref, theBait, theSwitch;
|
|
theBait = 1000;
|
|
theSwitch = 0;
|
|
_ref = [theSwitch, theBait];
|
|
theBait = _ref[0];
|
|
theSwitch = _ref[1];;alert(theBait);'>run: theBait</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">weatherReport </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> weatherReport <span class="String"><span class="String">"</span>Berkeley, CA<span class="String">"</span></span>
|
|
</pre><pre class="idle"><span class="Storage">var</span> _ref, city, forecast, temp, weatherReport;
|
|
<span class="FunctionName">weatherReport</span> = <span class="Storage">function</span>(<span class="FunctionArgument">location</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>];
|
|
};
|
|
_ref <span class="Keyword">=</span> weatherReport(<span class="String"><span class="String">"</span>Berkeley, CA<span class="String">"</span></span>);
|
|
city <span class="Keyword">=</span> _ref[<span class="Number">0</span>];
|
|
temp <span class="Keyword">=</span> _ref[<span class="Number">1</span>];
|
|
forecast <span class="Keyword">=</span> _ref[<span class="Number">2</span>];
|
|
</pre><button onclick='javascript: var _ref, city, forecast, temp, weatherReport;
|
|
weatherReport = function(location) {
|
|
return [location, 72, "Mostly Sunny"];
|
|
};
|
|
_ref = weatherReport("Berkeley, CA");
|
|
city = _ref[0];
|
|
temp = _ref[1];
|
|
forecast = _ref[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="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>
|
|
]
|
|
|
|
{poet: {name, address: [street, city]}} <span class="Keyword">=</span> futurists
|
|
</pre><pre class="idle"><span class="Storage">var</span> _ref, _ref2, _ref3, city, futurists, name, 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>]
|
|
}
|
|
};
|
|
_ref <span class="Keyword">=</span> futurists;
|
|
_ref2 <span class="Keyword">=</span> _ref.poet;
|
|
name <span class="Keyword">=</span> _ref2.<span class="LibraryConstant">name</span>;
|
|
_ref3 <span class="Keyword">=</span> _ref2.address;
|
|
street <span class="Keyword">=</span> _ref3[<span class="Number">0</span>];
|
|
city <span class="Keyword">=</span> _ref3[<span class="Number">1</span>];
|
|
</pre><button onclick='javascript: var _ref, _ref2, _ref3, city, futurists, name, street;
|
|
futurists = {
|
|
sculptor: "Umberto Boccioni",
|
|
painter: "Vladimir Burliuk",
|
|
poet: {
|
|
name: "F.T. Marinetti",
|
|
address: ["Via Roma 42R", "Bellagio, Italy 22021"]
|
|
}
|
|
};
|
|
_ref = futurists;
|
|
_ref2 = _ref.poet;
|
|
name = _ref2.name;
|
|
_ref3 = _ref2.address;
|
|
street = _ref3[0];
|
|
city = _ref3[1];;alert(name + " — " + street);'>run: name + " — " + 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> _ref, 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>;
|
|
_ref <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> _ref[<span class="Number">0</span>];
|
|
contents <span class="Keyword">=</span> __slice.<span class="LibraryFunction">call</span>(_ref, <span class="Number">1</span>, _ref.<span class="LibraryConstant">length</span> <span class="Keyword">-</span> <span class="Number">1</span>);
|
|
close <span class="Keyword">=</span> _ref[_ref.<span class="LibraryConstant">length</span> <span class="Keyword">-</span> <span class="Number">1</span>];
|
|
</pre><button onclick='javascript: var _ref, close, contents, open, tag;
|
|
var __slice = Array.prototype.slice;
|
|
tag = "<impossible>";
|
|
_ref = tag.split("");
|
|
open = _ref[0];
|
|
contents = __slice.call(_ref, 1, _ref.length - 1);
|
|
close = _ref[_ref.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
|
|
|
|
$(<span class="String"><span class="String">'</span>.shopping_cart<span class="String">'</span></span>).bind <span class="String"><span class="String">'</span>click<span class="String">'</span></span>, <span class="FunctionArgument">(</span><span class="FunctionArgument">event</span><span class="FunctionArgument">)</span> <span class="Storage">=></span>
|
|
<span class="Variable">@customer</span>.purchase <span class="Variable">@cart</span>
|
|
</pre><pre class="idle"><span class="Storage">var</span> Account;
|
|
<span class="Storage">var</span> <span class="FunctionName">__bind</span> = <span class="Storage">function</span>(<span class="FunctionArgument">func, context</span>) {
|
|
<span class="Keyword">return</span> <span class="Storage">function</span>(){ <span class="Keyword">return</span> func.<span class="LibraryFunction">apply</span>(context, arguments); };
|
|
};
|
|
<span class="FunctionName">Account</span> = <span class="Storage">function</span>(<span class="FunctionArgument">customer, cart</span>) {
|
|
<span class="Variable">this</span>.customer <span class="Keyword">=</span> customer;
|
|
<span class="Variable">this</span>.cart <span class="Keyword">=</span> cart;
|
|
<span class="Keyword">return</span> <span class="Keyword">$</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>
|
|
<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 a bit awkward. You 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 prevents accidental fall-through, and can convert the <tt>switch</tt>
|
|
into 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 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 relax
|
|
<span class="Keyword">when</span> <span class="String"><span class="String">"</span>Thu<span class="String">"</span></span> <span class="Keyword">then</span> go iceFishing
|
|
<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> bingoDay
|
|
go 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 church
|
|
<span class="Keyword">else</span> go work
|
|
</pre><pre class="idle"><span class="Keyword">switch</span> (day) {
|
|
<span class="Keyword">case</span> <span class="String"><span class="String">"</span>Mon<span class="String">"</span></span>:
|
|
<span class="LibraryFunction">go</span>(work);
|
|
<span class="Keyword">break</span>;
|
|
<span class="Keyword">case</span> <span class="String"><span class="String">"</span>Tue<span class="String">"</span></span>:
|
|
<span class="LibraryFunction">go</span>(relax);
|
|
<span class="Keyword">break</span>;
|
|
<span class="Keyword">case</span> <span class="String"><span class="String">"</span>Thu<span class="String">"</span></span>:
|
|
<span class="LibraryFunction">go</span>(iceFishing);
|
|
<span class="Keyword">break</span>;
|
|
<span class="Keyword">case</span> <span class="String"><span class="String">"</span>Fri<span class="String">"</span></span>:
|
|
<span class="Keyword">case</span> <span class="String"><span class="String">"</span>Sat<span class="String">"</span></span>:
|
|
<span class="Keyword">if</span> (day <span class="Keyword">===</span> bingoDay) {
|
|
<span class="LibraryFunction">go</span>(bingo);
|
|
<span class="LibraryFunction">go</span>(dancing);
|
|
}
|
|
<span class="Keyword">break</span>;
|
|
<span class="Keyword">case</span> <span class="String"><span class="String">"</span>Sun<span class="String">"</span></span>:
|
|
<span class="LibraryFunction">go</span>(church);
|
|
<span class="Keyword">break</span>;
|
|
<span class="Keyword">default</span>:
|
|
<span class="LibraryFunction">go</span>(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>
|
|
allHellBreaksLoose()
|
|
catsAndDogsLivingTogether()
|
|
<span class="Keyword">catch</span> error
|
|
print error
|
|
<span class="Keyword">finally</span>
|
|
cleanUp()
|
|
</pre><pre class="idle"><span class="Keyword">try</span> {
|
|
allHellBreaksLoose();
|
|
catsAndDogsLivingTogether();
|
|
} <span class="Keyword">catch</span> (error) {
|
|
<span class="LibraryFunction">print</span>(error);
|
|
} <span class="Keyword">finally</span> {
|
|
cleanUp();
|
|
}
|
|
</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>
|
|
Ruby-style string interpolation is included in CoffeeScript. Double-quoted
|
|
strings allow for interpolated values, while single-quoted strings are literal.
|
|
</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 class="String">}</span></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"> /\d+#{sep}\d+#{sep}\d+/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="heredocs" class="bookmark"></span>
|
|
<b class="header">Multiline Strings, Heredocs, and Block Comments</b>
|
|
Multiline strings are allowed in CoffeeScript.
|
|
</p>
|
|
<div class='code'><pre class="idle">mobyDick <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> mobyDick;
|
|
mobyDick <span class="Keyword">=</span> <span class="String"><span class="String">"</span>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...<span class="String">"</span></span>;
|
|
</pre><button onclick='javascript: var mobyDick;
|
|
mobyDick = "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(mobyDick);'>run: mobyDick</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>
|
|
<p>
|
|
Sometimes you'd like to pass a block comment through to the generated
|
|
JavaScript. For example, when you need to embed a licensing header at
|
|
the top of a file. Block comments, which mirror the synax for heredocs,
|
|
are preserved in the generated code.
|
|
</p>
|
|
<div class='code'><pre class="idle"><span class="Comment"><span class="Comment">###</span></span>
|
|
<span class="Comment">CoffeeScript Compiler v0.9.4</span>
|
|
<span class="Comment">Released under the MIT License</span>
|
|
<span class="Comment">###</span>
|
|
</pre><pre class="idle"><span class="Comment"><span class="Comment">/*</span></span>
|
|
<span class="Comment">CoffeeScript Compiler v0.9.4</span>
|
|
<span class="Comment">Released under the MIT License</span>
|
|
<span class="Comment"><span class="Comment">*/</span></span>
|
|
</pre><br class='clear' /></div>
|
|
|
|
<h2>
|
|
<span id="cake" class="bookmark"></span>
|
|
Cake, and Cakefiles
|
|
</h2>
|
|
|
|
<p>
|
|
CoffeeScript includes a simple build system similar to
|
|
<a href="http://www.gnu.org/software/make/">Make</a> and
|
|
<a href="http://rake.rubyforge.org/">Rake</a>. 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 and options, 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. If your task takes a command-line
|
|
option, you can define the option with short and long flags, and it will
|
|
be made available in the <tt>options</tt> object. Here's a task that uses
|
|
the Node.js API to rebuild CoffeeScript's parser:
|
|
</p>
|
|
<div class='code'><pre class="idle">fs <span class="Keyword">=</span> require <span class="String"><span class="String">'</span>fs<span class="String">'</span></span>
|
|
|
|
option <span class="String"><span class="String">'</span>-o<span class="String">'</span></span>, <span class="String"><span class="String">'</span>--output [DIR]<span class="String">'</span></span>, <span class="String"><span class="String">'</span>directory for compiled code<span class="String">'</span></span>
|
|
|
|
task <span class="String"><span class="String">'</span>build:parser<span class="String">'</span></span>, <span class="String"><span class="String">'</span>rebuild the Jison parser<span class="String">'</span></span>, <span class="FunctionArgument">(</span><span class="FunctionArgument">options</span><span class="FunctionArgument">)</span> <span class="Storage">-></span>
|
|
require <span class="String"><span class="String">'</span>jison<span class="String">'</span></span>
|
|
code <span class="Keyword">=</span> require(<span class="String"><span class="String">'</span>./lib/grammar<span class="String">'</span></span>).parser.generate()
|
|
dir <span class="Keyword">=</span> options.output <span class="Keyword">or</span> <span class="String"><span class="String">'</span>lib<span class="String">'</span></span>
|
|
fs.writeFile <span class="String"><span class="String">"</span><span class="String"><span class="String">#{</span>dir<span class="String">}</span></span>/parser.js<span class="String">"</span></span>, code
|
|
</pre><pre class="idle"><span class="Storage">var</span> fs;
|
|
fs <span class="Keyword">=</span> require(<span class="String"><span class="String">'</span>fs<span class="String">'</span></span>);
|
|
option(<span class="String"><span class="String">'</span>-o<span class="String">'</span></span>, <span class="String"><span class="String">'</span>--output [DIR]<span class="String">'</span></span>, <span class="String"><span class="String">'</span>directory for compiled code<span class="String">'</span></span>);
|
|
task(<span class="String"><span class="String">'</span>build:parser<span class="String">'</span></span>, <span class="String"><span class="String">'</span>rebuild the Jison parser<span class="String">'</span></span>, <span class="Storage">function</span>(options) {
|
|
<span class="Storage">var</span> code, dir;
|
|
require(<span class="String"><span class="String">'</span>jison<span class="String">'</span></span>);
|
|
code <span class="Keyword">=</span> require(<span class="String"><span class="String">'</span>./lib/grammar<span class="String">'</span></span>).parser.generate();
|
|
dir <span class="Keyword">=</span> options.output <span class="Keyword">||</span> <span class="String"><span class="String">'</span>lib<span class="String">'</span></span>;
|
|
<span class="Keyword">return</span> fs.writeFile(<span class="String"><span class="String">"</span><span class="String">"</span></span> <span class="Keyword">+</span> (dir) <span class="Keyword">+</span> <span class="String"><span class="String">"</span>/parser.js<span class="String">"</span></span>, code);
|
|
});
|
|
</pre><br class='clear' /></div>
|
|
<p>
|
|
If you need to invoke one task before another — for example, running
|
|
<tt>build</tt> before <tt>test</tt>, you can use the <tt>invoke</tt> function:
|
|
<tt>invoke 'build'</tt>
|
|
</p>
|
|
|
|
<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>yeungda</b>'s <a href="http://github.com/yeungda/jcoffeescript">JCoffeeScript</a>
|
|
— A Java Library that uses Rhino to compile CoffeeScript, allowing
|
|
compilation within Java projects or on systems that Node.js doesn't support.
|
|
</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>wavded</b>'s <a href="http://github.com/wavded/gedit-coffeescript">gedit-coffeescript</a>
|
|
— a CoffeeScript syntax highlighter for the gedit text editor.
|
|
</li>
|
|
<li>
|
|
<b>yeungda</b>'s <a href="http://yeungda.github.com/coffeescript-idea/">coffeescript-idea</a>
|
|
— a plugin for IntelliJ IDEA and RubyMine providing syntax highlighting.
|
|
</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>
|
|
<li>
|
|
<b>dsc</b>'s <a href="http://github.com/dsc/coffeecup">CoffeeCup</a>
|
|
— a Python WSGI middleware that compiles CoffeeScript to JavaScript
|
|
on-demand during development.
|
|
</li>
|
|
<li>
|
|
<b>sutto</b>'s <a href="http://github.com/Sutto/barista">Barista</a>
|
|
— a BistroCar alternative that integrates well with
|
|
<a href="http://documentcloud.github.com/jammit">Jammit</a> and Rails 3.
|
|
</li>
|
|
<li>
|
|
<b>inem</b> and <b>gerad</b>'s <a href="http://github.com/gerad/coffee-haml-filter">coffee-haml-filter</a>
|
|
— a custom filter for rendering CoffeeScript inline within
|
|
<a href="http://haml-lang.com/">HAML</a> templates.
|
|
</li>
|
|
<li>
|
|
<b>chrislloyd</b>'s <a href="http://github.com/chrislloyd/roast">Roast</a>
|
|
— a CoffeeScript compiler plug-in that allows you to include external
|
|
source files.
|
|
</li>
|
|
<li>
|
|
<b>mauricemach</b>'s <a href="http://github.com/mauricemach/coffeekup">CoffeeKup</a>
|
|
— Markup as CoffeeScript. After _why's
|
|
<a href="http://markaby.github.com/">Markaby</a>.
|
|
</li>
|
|
<li>
|
|
<b>jashkenas</b>'s <a href="http://jashkenas.github.com/docco/">Docco</a>
|
|
— a quick-and-dirty literate-programming-style documentation generator
|
|
for CoffeeScript. Used to produce the annotated source.
|
|
</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;">0.9.4</b>
|
|
CoffeeScript now uses appropriately-named temporary variables, and recycles
|
|
their references after use. Added <tt>require.extensions</tt> support for
|
|
<b>Node.js 0.3</b>. Loading CoffeeScript in the browser now adds just a
|
|
single <tt>CoffeeScript</tt> object to global scope.
|
|
Fixes for implicit object and block comment edge cases.
|
|
</p>
|
|
|
|
<p>
|
|
<b class="header" style="margin-top: 20px;">0.9.3</b>
|
|
CoffeeScript <tt>switch</tt> statements now compile into JS <tt>switch</tt>
|
|
statements — they previously compiled into <tt>if/else</tt> chains
|
|
for JavaScript 1.3 compatibility.
|
|
Soaking a function invocation is now supported. Users of the RubyMine
|
|
editor should now be able to use <tt>--watch</tt> mode.
|
|
</p>
|
|
|
|
<p>
|
|
<b class="header" style="margin-top: 20px;">0.9.2</b>
|
|
Specifying the start and end of a range literal is now optional, eg. <tt>array[3..]</tt>.
|
|
You can now say <tt>a not instanceof b</tt>.
|
|
Fixed important bugs with nested significant and non-significant indentation (Issue #637).
|
|
Added a <tt>--require</tt> flag that allows you to hook into the <tt>coffee</tt> command.
|
|
Added a custom <tt>jsl.conf</tt> file for our preferred JavaScriptLint setup.
|
|
Sped up Jison grammar compilation time by flattening rules for operations.
|
|
Block comments can now be used with JavaScript-minifier-friendly syntax.
|
|
Added JavaScript's compound assignment bitwise operators. Bugfixes to
|
|
implicit object literals with leading number and string keys, as the subject
|
|
of implicit calls, and as part of compound assignment.
|
|
</p>
|
|
|
|
<p>
|
|
<b class="header" style="margin-top: 20px;">0.9.1</b>
|
|
Bugfix release for <b>0.9.1</b>. Greatly improves the handling of mixed
|
|
implicit objects, implicit function calls, and implicit indentation.
|
|
String and regex interpolation is now strictly <tt>#{ ... }</tt> (Ruby style).
|
|
The compiler now takes a <tt>--require</tt> flag, which specifies scripts
|
|
to run before compilation.
|
|
</p>
|
|
|
|
<p>
|
|
<b class="header" style="margin-top: 20px;">0.9.0</b>
|
|
The CoffeeScript <b>0.9</b> series is considered to be a release candidate
|
|
for <b>1.0</b>; let's give her a shakedown cruise. <b>0.9.0</b> introduces a massive
|
|
backwards-incompatible change: Assignment now uses <tt>=</tt>, and object
|
|
literals use <tt>:</tt>, as in JavaScript. This allows us to have implicit
|
|
object literals, and YAML-style object definitions. Half assignments are
|
|
removed, in favor of <tt>+=</tt>, <tt>or=</tt>, and friends.
|
|
Interpolation now uses a hash mark <tt>#</tt> instead of the dollar sign
|
|
<tt>$</tt> — because dollar signs may be part of a valid JS identifier.
|
|
Downwards range comprehensions are now safe again, and are optimized to
|
|
straight for loops when created with integer endpoints.
|
|
A fast, unguarded form of object comprehension was added:
|
|
<tt>for all key, value of object</tt>. Mentioning the <tt>super</tt> keyword
|
|
with no arguments now forwards all arguments passed to the function,
|
|
as in Ruby. If you extend class <tt>B</tt> from parent class <tt>A</tt>, if
|
|
<tt>A</tt> has an <tt>extended</tt> method defined, it will be called, passing in <tt>B</tt> —
|
|
this enables static inheritance, among other things. Cleaner output for
|
|
functions bound with the fat arrow. <tt>@variables</tt> can now be used
|
|
in parameter lists, with the parameter being automatically set as a property
|
|
on the object — useful in constructors and setter functions.
|
|
Constructor functions can now take splats.
|
|
</p>
|
|
|
|
<p>
|
|
<b class="header" style="margin-top: 20px;">0.7.2</b>
|
|
Quick bugfix (right after 0.7.1) for a problem that prevented <tt>coffee</tt>
|
|
command-line options from being parsed in some circumstances.
|
|
</p>
|
|
|
|
<p>
|
|
<b class="header" style="margin-top: 20px;">0.7.1</b>
|
|
Block-style comments are now passed through and printed as JavaScript block
|
|
comments -- making them useful for licenses and copyright headers. Better
|
|
support for running coffee scripts standalone via hashbangs.
|
|
Improved syntax errors for tokens that are not in the grammar.
|
|
</p>
|
|
|
|
<p>
|
|
<b class="header" style="margin-top: 20px;">0.7.0</b>
|
|
Official CoffeeScript variable style is now camelCase, as in JavaScript.
|
|
Reserved words are now allowed as object keys, and will be quoted for you.
|
|
Range comprehensions now generate cleaner code, but you have to specify <tt>by -1</tt>
|
|
if you'd like to iterate downward. Reporting of syntax errors is greatly
|
|
improved from the previous release. Running <tt>coffee</tt> with no arguments
|
|
now launches the REPL, with Readline support. The <tt><-</tt> bind operator
|
|
has been removed from CoffeeScript. The <tt>loop</tt> keyword was added,
|
|
which is equivalent to a <tt>while true</tt> loop. Comprehensions that contain
|
|
closures will now close over their variables, like the semantics of a <tt>forEach</tt>.
|
|
You can now use bound function in class definitions (bound to the instance).
|
|
For consistency, <tt>a in b</tt> is now an array presence check, and <tt>a of b</tt>
|
|
is an object-key check. Comments are no longer passed through to the generated
|
|
JavaScript.
|
|
</p>
|
|
|
|
<p>
|
|
<b class="header" style="margin-top: 20px;">0.6.2</b>
|
|
The <tt>coffee</tt> command will now preserve directory structure when
|
|
compiling a directory full of scripts. Fixed two omissions that were preventing
|
|
the CoffeeScript compiler from running live within Internet Explorer.
|
|
There's now a syntax for block comments, similar in spirit to CoffeeScript's heredocs.
|
|
ECMA Harmony DRY-style pattern matching is now supported, where the name
|
|
of the property is the same as the name of the value: <tt>{name, length}: func</tt>.
|
|
Pattern matching is now allowed within comprehension variables. <tt>unless</tt>
|
|
is now allowed in block form. <tt>until</tt> loops were added, as the inverse
|
|
of <tt>while</tt> loops. <tt>switch</tt> statements are now allowed without
|
|
switch object clauses. Compatible
|
|
with Node.js <b>v0.1.95</b>.
|
|
</p>
|
|
|
|
<p>
|
|
<b class="header" style="margin-top: 20px;">0.6.1</b>
|
|
Upgraded CoffeeScript for compatibility with the new Node.js <b>v0.1.90</b>
|
|
series.
|
|
</p>
|
|
|
|
<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/liamoc">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, noWrap: 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>
|