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diff --git a/lazy_static/index.html b/lazy_static/index.html new file mode 100644 index 0000000..037359f --- /dev/null +++ b/lazy_static/index.html @@ -0,0 +1,174 @@ +<!DOCTYPE html> +<html lang="en"> +<head> + <meta charset="utf-8"> + <meta name="viewport" content="width=device-width, initial-scale=1.0"> + <meta name="generator" content="rustdoc"> + <meta name="description" content="API documentation for the Rust `lazy_static` crate."> + <meta name="keywords" content="rust, rustlang, rust-lang, lazy_static"> + + <title>lazy_static - Rust</title> + + <link rel="stylesheet" type="text/css" href="../main.css"> + + + +</head> +<body class="rustdoc"> + <!--[if lte IE 8]> + <div class="warning"> + This old browser is unsupported and will most likely display funky + things. + </div> + <![endif]--> + + + + <section class="sidebar"> + + <p class='location'></p><script>window.sidebarCurrent = {name: 'lazy_static', ty: 'mod', relpath: '../'};</script> + </section> + + <nav class="sub"> + <form class="search-form js-only"> + <div class="search-container"> + <input class="search-input" name="search" + autocomplete="off" + placeholder="Click or press 'S' to search, '?' for more options..." + type="search"> + </div> + </form> + </nav> + + <section id='main' class="content mod"> +<h1 class='fqn'><span class='in-band'>Crate <a class='mod' href=''>lazy_static</a></span><span class='out-of-band'><span id='render-detail'> + <a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs"> + [<span class='inner'>−</span>] + </a> + </span><a id='src-0' class='srclink' href='../src/lazy_static/lib.rs.html#1-124' title='goto source code'>[src]</a></span></h1> +<div class='docblock'><p>A macro for declaring lazily evaluated statics.</p> + +<p>Using this macro, it is possible to have <code>static</code>s that require code to be +executed at runtime in order to be initialized. +This includes anything requiring heap allocations, like vectors or hash maps, +as well as anything that requires function calls to be computed.</p> + +<h1 id="syntax" class='section-header'><a + href="#syntax">Syntax</a></h1><pre class='rust rust-example-rendered'> +<span class='macro'>lazy_static</span><span class='macro'>!</span> { + [<span class='kw'>pub</span>] <span class='kw'>static</span> <span class='kw-2'>ref</span> <span class='ident'>NAME_1</span>: <span class='ident'>TYPE_1</span> <span class='op'>=</span> <span class='ident'>EXPR_1</span>; + [<span class='kw'>pub</span>] <span class='kw'>static</span> <span class='kw-2'>ref</span> <span class='ident'>NAME_2</span>: <span class='ident'>TYPE_2</span> <span class='op'>=</span> <span class='ident'>EXPR_2</span>; + ... + [<span class='kw'>pub</span>] <span class='kw'>static</span> <span class='kw-2'>ref</span> <span class='ident'>NAME_N</span>: <span class='ident'>TYPE_N</span> <span class='op'>=</span> <span class='ident'>EXPR_N</span>; +} +</pre> + +<h1 id="semantic" class='section-header'><a + href="#semantic">Semantic</a></h1> +<p>For a given <code>static ref NAME: TYPE = EXPR;</code>, the macro generates a +unique type that implements <code>Deref<TYPE></code> and stores it in a static with name <code>NAME</code>.</p> + +<p>On first deref, <code>EXPR</code> gets evaluated and stored internally, such that all further derefs +can return a reference to the same object.</p> + +<p>Like regular <code>static mut</code>s, this macro only works for types that fulfill the <code>Sync</code> +trait.</p> + +<h1 id="example" class='section-header'><a + href="#example">Example</a></h1> +<p>Using the macro:</p> +<pre class='rust rust-example-rendered'> +<span class='attribute'>#[<span class='ident'>macro_use</span>]</span> +<span class='kw'>extern</span> <span class='kw'>crate</span> <span class='ident'>lazy_static</span>; + +<span class='kw'>use</span> <span class='ident'>std</span>::<span class='ident'>collections</span>::<span class='ident'>HashMap</span>; + +<span class='macro'>lazy_static</span><span class='macro'>!</span> { + <span class='kw'>static</span> <span class='kw-2'>ref</span> <span class='ident'>HASHMAP</span>: <span class='ident'>HashMap</span><span class='op'><</span><span class='ident'>u32</span>, <span class='kw-2'>&</span><span class='lifetime'>'static</span> <span class='ident'>str</span><span class='op'>></span> <span class='op'>=</span> { + <span class='kw'>let</span> <span class='kw-2'>mut</span> <span class='ident'>m</span> <span class='op'>=</span> <span class='ident'>HashMap</span>::<span class='ident'>new</span>(); + <span class='ident'>m</span>.<span class='ident'>insert</span>(<span class='number'>0</span>, <span class='string'>"foo"</span>); + <span class='ident'>m</span>.<span class='ident'>insert</span>(<span class='number'>1</span>, <span class='string'>"bar"</span>); + <span class='ident'>m</span>.<span class='ident'>insert</span>(<span class='number'>2</span>, <span class='string'>"baz"</span>); + <span class='ident'>m</span> + }; + <span class='kw'>static</span> <span class='kw-2'>ref</span> <span class='ident'>COUNT</span>: <span class='ident'>usize</span> <span class='op'>=</span> <span class='ident'>HASHMAP</span>.<span class='ident'>len</span>(); + <span class='kw'>static</span> <span class='kw-2'>ref</span> <span class='ident'>NUMBER</span>: <span class='ident'>u32</span> <span class='op'>=</span> <span class='ident'>times_two</span>(<span class='number'>21</span>); +} + +<span class='kw'>fn</span> <span class='ident'>times_two</span>(<span class='ident'>n</span>: <span class='ident'>u32</span>) <span class='op'>-></span> <span class='ident'>u32</span> { <span class='ident'>n</span> <span class='op'>*</span> <span class='number'>2</span> } + +<span class='kw'>fn</span> <span class='ident'>main</span>() { + <span class='macro'>println</span><span class='macro'>!</span>(<span class='string'>"The map has {} entries."</span>, <span class='op'>*</span><span class='ident'>COUNT</span>); + <span class='macro'>println</span><span class='macro'>!</span>(<span class='string'>"The entry for `0` is \"{}\"."</span>, <span class='ident'>HASHMAP</span>.<span class='ident'>get</span>(<span class='kw-2'>&</span><span class='number'>0</span>).<span class='ident'>unwrap</span>()); + <span class='macro'>println</span><span class='macro'>!</span>(<span class='string'>"A expensive calculation on a static results in: {}."</span>, <span class='op'>*</span><span class='ident'>NUMBER</span>); +} +</pre> + +<h1 id="implementation-details" class='section-header'><a + href="#implementation-details">Implementation details</a></h1> +<p>The <code>Deref</code> implementation uses a hidden <code>static mut</code> that is guarded by a atomic check +using the <code>sync::Once</code> abstraction. All lazily evaluated values are currently +put in a heap allocated box, due to the Rust language currently not providing any way to +define uninitialized <code>static mut</code> values.</p> +</div><h2 id='macros' class='section-header'><a href="#macros">Macros</a></h2> +<table> + <tr class=' module-item'> + <td><a class='macro' href='macro.lazy_static!.html' + title='lazy_static::lazy_static!'>lazy_static!</a></td> + <td class='docblock short'> + + </td> + </tr> + </table></section> + <section id='search' class="content hidden"></section> + + <section class="footer"></section> + + <div id="help" class="hidden"> + <div class="shortcuts"> + <h1>Keyboard shortcuts</h1> + <dl> + <dt>?</dt> + <dd>Show this help dialog</dd> + <dt>S</dt> + <dd>Focus the search field</dd> + <dt>⇤</dt> + <dd>Move up in search results</dd> + <dt>⇥</dt> + <dd>Move down in search results</dd> + <dt>⏎</dt> + <dd>Go to active search result</dd> + </dl> + </div> + <div class="infos"> + <h1>Search tricks</h1> + <p> + Prefix searches with a type followed by a colon (e.g. + <code>fn:</code>) to restrict the search to a given type. + </p> + <p> + Accepted types are: <code>fn</code>, <code>mod</code>, + <code>struct</code>, <code>enum</code>, + <code>trait</code>, <code>typedef</code> (or + <code>tdef</code>). + </p> + <p> + Search functions by type signature (e.g. + <code>vec -> usize</code>) + </p> + </div> + </div> + + + + <script> + window.rootPath = "../"; + window.currentCrate = "lazy_static"; + window.playgroundUrl = ""; + </script> + <script src="../jquery.js"></script> + <script src="../main.js"></script> + + <script async src="../search-index.js"></script> +</body> +</html>
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