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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="Converts enum variants to strings."><title>Display in strum_macros - 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_macros" 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_macros/index.html">strum_macros</a><span class="version">0.26.4</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_macros/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_macros</a>::<wbr><a class="derive" href="#">Display</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#424-430">source</a> · <button id="toggle-all-docs" title="collapse all docs">[<span>−</span>]</button></span></div><pre class="rust item-decl"><code>#[derive(Display)]
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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>Converts enum variants to strings.</p>
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<p>Deriving <code>Display</code> on an enum prints out the given enum. This enables you to perform round
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trip style conversions from enum into string and back again for unit style variants. <code>Display</code>
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choose which serialization to used based on the following criteria:</p>
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<ol>
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<li>
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<p>If there is a <code>to_string</code> property, this value will be used. There can only be one per variant.</p>
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</li>
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<li>
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<p>Of the various <code>serialize</code> properties, the value with the longest length is chosen. If that
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behavior isn’t desired, you should use <code>to_string</code>.</p>
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</li>
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<li>
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<p>The name of the variant will be used if there are no <code>serialize</code> or <code>to_string</code> attributes.</p>
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</li>
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<li>
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<p>If the enum has a <code>strum(prefix = "some_value_")</code>, every variant will have that prefix prepended
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to the serialization.</p>
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</li>
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<li>
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<p>Enums with fields support string interpolation.
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Note this means the variant will not “round trip” if you then deserialize the string.</p>
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<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="attr">#[derive(strum_macros::Display)]
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</span><span class="kw">pub enum </span>Color {
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<span class="attr">#[strum(to_string = <span class="string">"saturation is {sat}"</span>)]
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</span>Red { sat: usize },
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<span class="attr">#[strum(to_string = <span class="string">"hue is {1}, saturation is {0}"</span>)]
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</span>Blue(usize, usize),
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}</code></pre></div>
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</li>
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</ol>
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<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="comment">// You need to bring the ToString trait into scope to use it
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</span><span class="kw">use </span>std::string::ToString;
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<span class="kw">use </span>strum_macros::Display;
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<span class="attr">#[derive(Display, Debug)]
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</span><span class="kw">enum </span>Color {
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<span class="attr">#[strum(serialize = <span class="string">"redred"</span>)]
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</span>Red,
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Green {
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range: usize,
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},
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Blue(usize),
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Yellow,
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<span class="attr">#[strum(to_string = <span class="string">"purple with {sat} saturation"</span>)]
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</span>Purple {
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sat: usize,
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},
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}
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<span class="comment">// uses the serialize string for Display
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</span><span class="kw">let </span>red = Color::Red;
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<span class="macro">assert_eq!</span>(String::from(<span class="string">"redred"</span>), <span class="macro">format!</span>(<span class="string">"{}"</span>, red));
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<span class="comment">// by default the variants Name
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</span><span class="kw">let </span>yellow = Color::Yellow;
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<span class="macro">assert_eq!</span>(String::from(<span class="string">"Yellow"</span>), yellow.to_string());
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<span class="comment">// or for string formatting
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</span><span class="macro">println!</span>(
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<span class="string">"blue: {} green: {}"</span>,
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Color::Blue(<span class="number">10</span>),
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Color::Green { range: <span class="number">42 </span>}
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);
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<span class="comment">// you can also use named fields in message
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</span><span class="kw">let </span>purple = Color::Purple { sat: <span class="number">10 </span>};
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<span class="macro">assert_eq!</span>(String::from(<span class="string">"purple with 10 saturation"</span>), purple.to_string());</code></pre></div>
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</div></details></section></div></main></body></html> |