19 lines
6.2 KiB
HTML
19 lines
6.2 KiB
HTML
<!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 `discriminant` fn in crate `nom`."><meta name="keywords" content="rust, rustlang, rust-lang, discriminant"><title>nom::lib::std::mem::discriminant - Rust</title><link rel="stylesheet" type="text/css" href="../../../../normalize.css"><link rel="stylesheet" type="text/css" href="../../../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" type="text/css" href="../../../../dark.css"><link rel="stylesheet" type="text/css" href="../../../../light.css" id="themeStyle"><script src="../../../../storage.js"></script><noscript><link rel="stylesheet" href="../../../../noscript.css"></noscript><link rel="shortcut icon" href="../../../../favicon.ico"><style type="text/css">#crate-search{background-image:url("../../../../down-arrow.svg");}</style></head><body class="rustdoc fn"><!--[if lte IE 8]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><div class="sidebar-menu">☰</div><a href='../../../../nom/index.html'><div class='logo-container'><img src='../../../../rust-logo.png' alt='logo'></div></a><div class="sidebar-elems"><p class='location'><a href='../../../index.html'>nom</a>::<wbr><a href='../../index.html'>lib</a>::<wbr><a href='../index.html'>std</a>::<wbr><a href='index.html'>mem</a></p><script>window.sidebarCurrent = {name: 'discriminant', ty: 'fn', relpath: ''};</script><script defer src="sidebar-items.js"></script></div></nav><div class="theme-picker"><button id="theme-picker" aria-label="Pick another theme!"><img src="../../../../brush.svg" width="18" alt="Pick another theme!"></button><div id="theme-choices"></div></div><script src="../../../../theme.js"></script><nav class="sub"><form class="search-form"><div class="search-container"><div><select id="crate-search"><option value="All crates">All crates</option></select><input class="search-input" name="search" disabled autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"></div><a id="settings-menu" href="../../../../settings.html"><img src="../../../../wheel.svg" width="18" alt="Change settings"></a></div></form></nav><section id="main" class="content"><h1 class='fqn'><span class='out-of-band'><span class='since' title='Stable since Rust version 1.21.0'>1.21.0</span><span id='render-detail'><a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs">[<span class='inner'>−</span>]</a></span><a class='srclink' href='https://doc.rust-lang.org/nightly/src/core/mem/mod.rs.html#867-869' title='goto source code'>[src]</a></span><span class='in-band'>Function <a href='../../../index.html'>nom</a>::<wbr><a href='../../index.html'>lib</a>::<wbr><a href='../index.html'>std</a>::<wbr><a href='index.html'>mem</a>::<wbr><a class="fn" href=''>discriminant</a></span></h1><pre class='rust fn'>pub fn discriminant<T>(v: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&</a>T) -> <a class="struct" href="../../../../nom/lib/std/mem/struct.Discriminant.html" title="struct nom::lib::std::mem::Discriminant">Discriminant</a><T></pre><div class='docblock'><p>Returns a value uniquely identifying the enum variant in <code>v</code>.</p>
|
||
<p>If <code>T</code> is not an enum, calling this function will not result in undefined behavior, but the
|
||
return value is unspecified.</p>
|
||
<h1 id="stability" class="section-header"><a href="#stability">Stability</a></h1>
|
||
<p>The discriminant of an enum variant may change if the enum definition changes. A discriminant
|
||
of some variant will not change between compilations with the same compiler.</p>
|
||
<h1 id="examples" class="section-header"><a href="#examples">Examples</a></h1>
|
||
<p>This can be used to compare enums that carry data, while disregarding
|
||
the actual data:</p>
|
||
|
||
<div class="example-wrap"><pre class="rust rust-example-rendered">
|
||
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">mem</span>;
|
||
|
||
<span class="kw">enum</span> <span class="ident">Foo</span> { <span class="ident">A</span>(<span class="kw-2">&</span><span class="lifetime">'static</span> <span class="ident">str</span>), <span class="ident">B</span>(<span class="ident">i32</span>), <span class="ident">C</span>(<span class="ident">i32</span>) }
|
||
|
||
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">mem</span>::<span class="ident">discriminant</span>(<span class="kw-2">&</span><span class="ident">Foo</span>::<span class="ident">A</span>(<span class="string">"bar"</span>)), <span class="ident">mem</span>::<span class="ident">discriminant</span>(<span class="kw-2">&</span><span class="ident">Foo</span>::<span class="ident">A</span>(<span class="string">"baz"</span>)));
|
||
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">mem</span>::<span class="ident">discriminant</span>(<span class="kw-2">&</span><span class="ident">Foo</span>::<span class="ident">B</span>(<span class="number">1</span>)), <span class="ident">mem</span>::<span class="ident">discriminant</span>(<span class="kw-2">&</span><span class="ident">Foo</span>::<span class="ident">B</span>(<span class="number">2</span>)));
|
||
<span class="macro">assert_ne</span><span class="macro">!</span>(<span class="ident">mem</span>::<span class="ident">discriminant</span>(<span class="kw-2">&</span><span class="ident">Foo</span>::<span class="ident">B</span>(<span class="number">3</span>)), <span class="ident">mem</span>::<span class="ident">discriminant</span>(<span class="kw-2">&</span><span class="ident">Foo</span>::<span class="ident">C</span>(<span class="number">3</span>)));</pre></div>
|
||
</div></section><section id="search" class="content hidden"></section><section class="footer"></section><script>window.rootPath = "../../../../";window.currentCrate = "nom";</script><script src="../../../../aliases.js"></script><script src="../../../../main.js"></script><script defer src="../../../../search-index.js"></script></body></html> |