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<!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="Add custom properties to enum variants."><title>EnumProperty in strum - Rust</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../static.files/SourceSerif4-Regular-46f98efaafac5295.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../static.files/FiraSans-Regular-018c141bf0843ffd.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../static.files/FiraSans-Medium-8f9a781e4970d388.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../static.files/SourceCodePro-Regular-562dcc5011b6de7d.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../static.files/SourceCodePro-Semibold-d899c5a5c4aeb14a.ttf.woff2"><link rel="stylesheet" href="../static.files/normalize-76eba96aa4d2e634.css"><link rel="stylesheet" href="../static.files/rustdoc-ac92e1bbe349e143.css"><meta name="rustdoc-vars" data-root-path="../" data-static-root-path="../static.files/" data-current-crate="strum" data-themes="" data-resource-suffix="" data-rustdoc-version="1.76.0 (07dca489a 2024-02-04)" data-channel="1.76.0" data-search-js="search-2b6ce74ff89ae146.js" data-settings-js="settings-4313503d2e1961c2.js" ><script src="../static.files/storage-f2adc0d6ca4d09fb.js"></script><script defer src="sidebar-items.js"></script><script defer src="../static.files/main-305769736d49e732.js"></script><noscript><link rel="stylesheet" href="../static.files/noscript-feafe1bb7466e4bd.css"></noscript><link rel="alternate icon" type="image/png" href="../static.files/favicon-16x16-8b506e7a72182f1c.png"><link rel="alternate icon" type="image/png" href="../static.files/favicon-32x32-422f7d1d52889060.png"><link rel="icon" type="image/svg+xml" href="../static.files/favicon-2c020d218678b618.svg"></head><body class="rustdoc derive"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="mobile-topbar"><button class="sidebar-menu-toggle">☰</button></nav><nav class="sidebar"><div class="sidebar-crate"><h2><a href="../strum/index.html">strum</a><span class="version">0.26.3</span></h2></div><div class="sidebar-elems"></div></nav><div class="sidebar-resizer"></div>
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<main><div class="width-limiter"><nav class="sub"><form class="search-form"><span></span><div id="sidebar-button" tabindex="-1"><a href="../strum/all.html" title="show sidebar"></a></div><input class="search-input" name="search" aria-label="Run search in the documentation" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><div id="help-button" tabindex="-1"><a href="../help.html" title="help">?</a></div><div id="settings-menu" tabindex="-1"><a href="../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../static.files/wheel-7b819b6101059cd0.svg"></a></div></form></nav><section id="main-content" class="content"><div class="main-heading"><h1>Derive Macro <a href="index.html">strum</a>::<wbr><a class="derive" href="#">EnumProperty</a><button id="copy-path" title="Copy item path to clipboard"><img src="../static.files/clipboard-7571035ce49a181d.svg" width="19" height="18" alt="Copy item path"></button></h1><span class="out-of-band"><a class="src" href="../src/strum_macros/lib.rs.html#804">source</a> · <button id="toggle-all-docs" title="collapse all docs">[<span>−</span>]</button></span></div><pre class="rust item-decl"><code>#[derive(EnumProperty)]
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{
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<span class="comment">// Attributes available to this derive:</span>
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#[strum]
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}
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</code></pre><details class="toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Add custom properties to enum variants.</p>
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<p>Enables the encoding of arbitrary constants into enum variants. This method
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currently only supports adding additional string values. Other types of literals are still
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experimental in the rustc compiler. The generated code works by nesting match statements.
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The first match statement matches on the type of the enum, and the inner match statement
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matches on the name of the property requested. This design works well for enums with a small
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number of variants and properties, but scales linearly with the number of variants so may not
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be the best choice in all situations.</p>
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<div class="example-wrap"><pre class="rust rust-example-rendered"><code>
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<span class="kw">use </span>strum_macros;
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<span class="comment">// bring the trait into scope
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</span><span class="kw">use </span>strum::EnumProperty;
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<span class="attr">#[derive(strum_macros::EnumProperty, Debug)]
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#[allow(dead_code)]
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</span><span class="kw">enum </span>Color {
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<span class="attr">#[strum(props(Red = <span class="string">"255"</span>, Blue = <span class="string">"255"</span>, Green = <span class="string">"255"</span>))]
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</span>White,
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<span class="attr">#[strum(props(Red = <span class="string">"0"</span>, Blue = <span class="string">"0"</span>, Green = <span class="string">"0"</span>))]
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</span>Black,
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<span class="attr">#[strum(props(Red = <span class="string">"0"</span>, Blue = <span class="string">"255"</span>, Green = <span class="string">"0"</span>))]
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</span>Blue,
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<span class="attr">#[strum(props(Red = <span class="string">"255"</span>, Blue = <span class="string">"0"</span>, Green = <span class="string">"0"</span>))]
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</span>Red,
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<span class="attr">#[strum(props(Red = <span class="string">"0"</span>, Blue = <span class="string">"0"</span>, Green = <span class="string">"255"</span>))]
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</span>Green,
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}
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<span class="kw">let </span>my_color = Color::Red;
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<span class="kw">let </span>display = <span class="macro">format!</span>(
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<span class="string">"My color is {:?}. It's RGB is {},{},{}"</span>,
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my_color,
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my_color.get_str(<span class="string">"Red"</span>).unwrap(),
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my_color.get_str(<span class="string">"Green"</span>).unwrap(),
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my_color.get_str(<span class="string">"Blue"</span>).unwrap()
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);
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<span class="macro">assert_eq!</span>(<span class="string">"My color is Red. It\'s RGB is 255,0,0"</span>, <span class="kw-2">&</span>display);</code></pre></div>
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