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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="Provides a `Visitor` access to the data of an enum in the input."><meta name="keywords" content="rust, rustlang, rust-lang, EnumAccess"><title>EnumAccess in serde::de - Rust</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceSerif4-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../FiraSans-Regular.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../FiraSans-Medium.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceCodePro-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceSerif4-Bold.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceCodePro-Semibold.ttf.woff2"><link rel="stylesheet" href="../../normalize.css"><link rel="stylesheet" href="../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" href="../../ayu.css" disabled><link rel="stylesheet" href="../../dark.css" disabled><link rel="stylesheet" href="../../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../../storage.js"></script><script defer src="sidebar-items.js"></script><script defer src="../../main.js"></script><noscript><link rel="stylesheet" href="../../noscript.css"></noscript><link rel="alternate icon" type="image/png" href="../../favicon-16x16.png"><link rel="alternate icon" type="image/png" href="../../favicon-32x32.png"><link rel="icon" type="image/svg+xml" href="../../favicon.svg"></head><body class="rustdoc trait"><!--[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">&#9776;</button><a class="sidebar-logo" href="../../serde/index.html"><div class="logo-container"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></div></a><h2></h2></nav><nav class="sidebar"><a class="sidebar-logo" href="../../serde/index.html"><div class="logo-container"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></div></a><h2 class="location"><a href="#">EnumAccess</a></h2><div class="sidebar-elems"><section><h3><a href="#required-associated-types">Required Associated Types</a></h3><ul class="block"><li><a href="#associatedtype.Error">Error</a></li><li><a href="#associatedtype.Variant">Variant</a></li></ul><h3><a href="#required-methods">Required Methods</a></h3><ul class="block"><li><a href="#tymethod.variant_seed">variant_seed</a></li></ul><h3><a href="#provided-methods">Provided Methods</a></h3><ul class="block"><li><a href="#method.variant">variant</a></li></ul><h3><a href="#implementors">Implementors</a></h3></section><h2><a href="index.html">In serde::de</a></h2></div></nav><main><div class="width-limiter"><nav class="sub"><form class="search-form"><div class="search-container"><span></span><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><div id="help-button" title="help" tabindex="-1"><a href="../../help.html">?</a></div><div id="settings-menu" tabindex="-1"><a href="../../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../../wheel.svg"></a></div></div></form></nav><section id="main-content" class="content"><div class="main-heading"><h1 class="fqn">Trait <a href="../index.html">serde</a>::<wbr><a href="index.html">de</a>::<wbr><a class="trait" href="#">EnumAccess</a><button id="copy-path" onclick="copy_path(this)" title="Copy item path to clipboard"><img src="../../clipboard.svg" width="19" height="18" alt="Copy item path"></button></h1><span class="out-of-band"><a class="srclink" href="../../src/serde/de/mod.rs.html#1981-2008">source</a> · <a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs">[<span class="inner">&#x2212;</span>]</a></span></div><div class="item-decl"><pre class="rust trait"><code>pub trait EnumAccess&lt;'de&gt;: Sized {
type <a href="#associatedtype.Error" class="associatedtype">Error</a>: <a class="trait" href="trait.Error.html" title="trait serde::de::Error">Error</a>;
type <a href="#associatedtype.Variant" class="associatedtype">Variant</a>: <a class="trait" href="trait.VariantAccess.html" title="trait serde::de::VariantAccess">VariantAccess</a>&lt;'de, Error = Self::<a class="associatedtype" href="trait.EnumAccess.html#associatedtype.Error" title="type serde::de::EnumAccess::Error">Error</a>&gt;;
fn <a href="#tymethod.variant_seed" class="fnname">variant_seed</a>&lt;V&gt;(<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;self,<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;seed: V<br>&nbsp;&nbsp;&nbsp;&nbsp;) -&gt; Result&lt;(V::<a class="associatedtype" href="trait.DeserializeSeed.html#associatedtype.Value" title="type serde::de::DeserializeSeed::Value">Value</a>, Self::<a class="associatedtype" href="trait.EnumAccess.html#associatedtype.Variant" title="type serde::de::EnumAccess::Variant">Variant</a>), Self::<a class="associatedtype" href="trait.EnumAccess.html#associatedtype.Error" title="type serde::de::EnumAccess::Error">Error</a>&gt;<br>&nbsp;&nbsp;&nbsp;&nbsp;<span class="where">where<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;V: <a class="trait" href="trait.DeserializeSeed.html" title="trait serde::de::DeserializeSeed">DeserializeSeed</a>&lt;'de&gt;</span>;
fn <a href="#method.variant" class="fnname">variant</a>&lt;V&gt;(self) -&gt; Result&lt;(V, Self::<a class="associatedtype" href="trait.EnumAccess.html#associatedtype.Variant" title="type serde::de::EnumAccess::Variant">Variant</a>), Self::<a class="associatedtype" href="trait.EnumAccess.html#associatedtype.Error" title="type serde::de::EnumAccess::Error">Error</a>&gt;<br>&nbsp;&nbsp;&nbsp;&nbsp;<span class="where">where<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;V: <a class="trait" href="../trait.Deserialize.html" title="trait serde::Deserialize">Deserialize</a>&lt;'de&gt;</span>,
{ ... }
}</code></pre></div><details class="rustdoc-toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Provides a <code>Visitor</code> access to the data of an enum in the input.</p>
<p><code>EnumAccess</code> is created by the <code>Deserializer</code> and passed to the
<code>Visitor</code> in order to identify which variant of an enum to deserialize.</p>
<h2 id="lifetime"><a href="#lifetime">Lifetime</a></h2>
<p>The <code>'de</code> lifetime of this trait is the lifetime of data that may be
borrowed by the deserialized enum variant. See the page <a href="https://serde.rs/lifetimes.html">Understanding
deserializer lifetimes</a> for a more detailed explanation of these lifetimes.</p>
<h2 id="example-implementation"><a href="#example-implementation">Example implementation</a></h2>
<p>The <a href="https://serde.rs/data-format.html">example data format</a> presented on the website demonstrates an
implementation of <code>EnumAccess</code> for a basic JSON data format.</p>
</div></details><h2 id="required-associated-types" class="small-section-header">Required Associated Types<a href="#required-associated-types" class="anchor"></a></h2><div class="methods"><details class="rustdoc-toggle method-toggle" open><summary><section id="associatedtype.Error" class="method has-srclink"><a class="srclink rightside" href="../../src/serde/de/mod.rs.html#1984">source</a><h4 class="code-header">type <a href="#associatedtype.Error" class="associatedtype">Error</a>: <a class="trait" href="trait.Error.html" title="trait serde::de::Error">Error</a></h4></section></summary><div class="docblock"><p>The error type that can be returned if some error occurs during
deserialization.</p>
</div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="associatedtype.Variant" class="method has-srclink"><a class="srclink rightside" href="../../src/serde/de/mod.rs.html#1987">source</a><h4 class="code-header">type <a href="#associatedtype.Variant" class="associatedtype">Variant</a>: <a class="trait" href="trait.VariantAccess.html" title="trait serde::de::VariantAccess">VariantAccess</a>&lt;'de, Error = Self::<a class="associatedtype" href="trait.EnumAccess.html#associatedtype.Error" title="type serde::de::EnumAccess::Error">Error</a>&gt;</h4></section></summary><div class="docblock"><p>The <code>Visitor</code> that will be used to deserialize the content of the enum
variant.</p>
</div></details></div><h2 id="required-methods" class="small-section-header">Required Methods<a href="#required-methods" class="anchor"></a></h2><div class="methods"><details class="rustdoc-toggle method-toggle" open><summary><section id="tymethod.variant_seed" class="method has-srclink"><a class="srclink rightside" href="../../src/serde/de/mod.rs.html#1993-1995">source</a><h4 class="code-header">fn <a href="#tymethod.variant_seed" class="fnname">variant_seed</a>&lt;V&gt;(<br>&nbsp;&nbsp;&nbsp;&nbsp;self,<br>&nbsp;&nbsp;&nbsp;&nbsp;seed: V<br>) -&gt; Result&lt;(V::<a class="associatedtype" href="trait.DeserializeSeed.html#associatedtype.Value" title="type serde::de::DeserializeSeed::Value">Value</a>, Self::<a class="associatedtype" href="trait.EnumAccess.html#associatedtype.Variant" title="type serde::de::EnumAccess::Variant">Variant</a>), Self::<a class="associatedtype" href="trait.EnumAccess.html#associatedtype.Error" title="type serde::de::EnumAccess::Error">Error</a>&gt;<span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;V: <a class="trait" href="trait.DeserializeSeed.html" title="trait serde::de::DeserializeSeed">DeserializeSeed</a>&lt;'de&gt;,</span></h4></section></summary><div class="docblock"><p><code>variant</code> is called to identify which variant to deserialize.</p>
<p><code>Deserialize</code> implementations should typically use <code>EnumAccess::variant</code>
instead.</p>
</div></details></div><h2 id="provided-methods" class="small-section-header">Provided Methods<a href="#provided-methods" class="anchor"></a></h2><div class="methods"><details class="rustdoc-toggle method-toggle" open><summary><section id="method.variant" class="method has-srclink"><a class="srclink rightside" href="../../src/serde/de/mod.rs.html#2002-2007">source</a><h4 class="code-header">fn <a href="#method.variant" class="fnname">variant</a>&lt;V&gt;(self) -&gt; Result&lt;(V, Self::<a class="associatedtype" href="trait.EnumAccess.html#associatedtype.Variant" title="type serde::de::EnumAccess::Variant">Variant</a>), Self::<a class="associatedtype" href="trait.EnumAccess.html#associatedtype.Error" title="type serde::de::EnumAccess::Error">Error</a>&gt;<span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;V: <a class="trait" href="../trait.Deserialize.html" title="trait serde::Deserialize">Deserialize</a>&lt;'de&gt;,</span></h4></section></summary><div class="docblock"><p><code>variant</code> is called to identify which variant to deserialize.</p>
<p>This method exists as a convenience for <code>Deserialize</code> implementations.
<code>EnumAccess</code> implementations should not override the default behavior.</p>
</div></details></div><h2 id="implementors" class="small-section-header">Implementors<a href="#implementors" class="anchor"></a></h2><div id="implementors-list"><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-EnumAccess%3C%27de%3E-for-CowStrDeserializer%3C%27a%2C%20E%3E" class="impl has-srclink"><a class="srclink rightside" href="../../src/serde/de/value.rs.html#749-762">source</a><a href="#impl-EnumAccess%3C%27de%3E-for-CowStrDeserializer%3C%27a%2C%20E%3E" class="anchor"></a><h3 class="code-header">impl&lt;'de, 'a, E&gt; <a class="trait" href="trait.EnumAccess.html" title="trait serde::de::EnumAccess">EnumAccess</a>&lt;'de&gt; for <a class="struct" href="value/struct.CowStrDeserializer.html" title="struct serde::de::value::CowStrDeserializer">CowStrDeserializer</a>&lt;'a, E&gt;<span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;E: <a class="trait" href="trait.Error.html" title="trait serde::de::Error">Error</a>,</span></h3></section></summary><div class="impl-items"><section id="associatedtype.Error-1" class="associatedtype trait-impl has-srclink"><a href="#associatedtype.Error-1" class="anchor"></a><h4 class="code-header">type <a href="#associatedtype.Error" class="associatedtype">Error</a> = E</h4></section><section id="associatedtype.Variant-1" class="associatedtype trait-impl has-srclink"><a href="#associatedtype.Variant-1" class="anchor"></a><h4 class="code-header">type <a href="#associatedtype.Variant" class="associatedtype">Variant</a> = UnitOnly&lt;E&gt;</h4></section></div></details><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-EnumAccess%3C%27de%3E-for-StrDeserializer%3C%27a%2C%20E%3E" class="impl has-srclink"><a class="srclink rightside" href="../../src/serde/de/value.rs.html#462-475">source</a><a href="#impl-EnumAccess%3C%27de%3E-for-StrDeserializer%3C%27a%2C%20E%3E" class="anchor"></a><h3 class="code-header">impl&lt;'de, 'a, E&gt; <a class="trait" href="trait.EnumAccess.html" title="trait serde::de::EnumAccess">EnumAccess</a>&lt;'de&gt; for <a class="struct" href="value/struct.StrDeserializer.html" title="struct serde::de::value::StrDeserializer">StrDeserializer</a>&lt;'a, E&gt;<span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;E: <a class="trait" href="trait.Error.html" title="trait serde::de::Error">Error</a>,</span></h3></section></summary><div class="impl-items"><section id="associatedtype.Error-2" class="associatedtype trait-impl has-srclink"><a href="#associatedtype.Error-2" class="anchor"></a><h4 class="code-header">type <a href="#associatedtype.Error" class="associatedtype">Error</a> = E</h4></section><section id="associatedtype.Variant-2" class="associatedtype trait-impl has-srclink"><a href="#associatedtype.Variant-2" class="anchor"></a><h4 class="code-header">type <a href="#associatedtype.Variant" class="associatedtype">Variant</a> = UnitOnly&lt;E&gt;</h4></section></div></details><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-EnumAccess%3C%27de%3E-for-MapAccessDeserializer%3CA%3E" class="impl has-srclink"><a class="srclink rightside" href="../../src/serde/de/value.rs.html#1493-1509">source</a><a href="#impl-EnumAccess%3C%27de%3E-for-MapAccessDeserializer%3CA%3E" class="anchor"></a><h3 class="code-header">impl&lt;'de, A&gt; <a class="trait" href="trait.EnumAccess.html" title="trait serde::de::EnumAccess">EnumAccess</a>&lt;'de&gt; for <a class="struct" href="value/struct.MapAccessDeserializer.html" title="struct serde::de::value::MapAccessDeserializer">MapAccessDeserializer</a>&lt;A&gt;<span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;A: <a class="trait" href="trait.MapAccess.html" title="trait serde::de::MapAccess">MapAccess</a>&lt;'de&gt;,</span></h3></section></summary><div class="impl-items"><section id="associatedtype.Error-3" class="associatedtype trait-impl has-srclink"><a href="#associatedtype.Error-3" class="anchor"></a><h4 class="code-header">type <a href="#associatedtype.Error" class="associatedtype">Error</a> = &lt;A as <a class="trait" href="trait.MapAccess.html" title="trait serde::de::MapAccess">MapAccess</a>&lt;'de&gt;&gt;::<a class="associatedtype" href="trait.MapAccess.html#associatedtype.Error" title="type serde::de::MapAccess::Error">Error</a></h4></section><section id="associatedtype.Variant-3" class="associatedtype trait-impl has-srclink"><a href="#associatedtype.Variant-3" class="anchor"></a><h4 class="code-header">type <a href="#associatedtype.Variant" class="associatedtype">Variant</a> = MapAsEnum&lt;A&gt;</h4></section></div></details><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-EnumAccess%3C%27de%3E-for-BorrowedStrDeserializer%3C%27de%2C%20E%3E" class="impl has-srclink"><a class="srclink rightside" href="../../src/serde/de/value.rs.html#541-554">source</a><a href="#impl-EnumAccess%3C%27de%3E-for-BorrowedStrDeserializer%3C%27de%2C%20E%3E" class="anchor"></a><h3 class="code-header">impl&lt;'de, E&gt; <a class="trait" href="trait.EnumAccess.html" title="trait serde::de::EnumAccess">EnumAccess</a>&lt;'de&gt; for <a class="struct" href="value/struct.BorrowedStrDeserializer.html" title="struct serde::de::value::BorrowedStrDeserializer">BorrowedStrDeserializer</a>&lt;'de, E&gt;<span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;E: <a class="trait" href="trait.Error.html" title="trait serde::de::Error">Error</a>,</span></h3></section></summary><div class="impl-items"><section id="associatedtype.Error-4" class="associatedtype trait-impl has-srclink"><a href="#associatedtype.Error-4" class="anchor"></a><h4 class="code-header">type <a href="#associatedtype.Error" class="associatedtype">Error</a> = E</h4></section><section id="associatedtype.Variant-4" class="associatedtype trait-impl has-srclink"><a href="#associatedtype.Variant-4" class="anchor"></a><h4 class="code-header">type <a href="#associatedtype.Variant" class="associatedtype">Variant</a> = UnitOnly&lt;E&gt;</h4></section></div></details><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-EnumAccess%3C%27de%3E-for-StringDeserializer%3CE%3E" class="impl has-srclink"><a class="srclink rightside" href="../../src/serde/de/value.rs.html#643-656">source</a><a href="#impl-EnumAccess%3C%27de%3E-for-StringDeserializer%3CE%3E" class="anchor"></a><h3 class="code-header">impl&lt;'de, E&gt; <a class="trait" href="trait.EnumAccess.html" title="trait serde::de::EnumAccess">EnumAccess</a>&lt;'de&gt; for <a class="struct" href="value/struct.StringDeserializer.html" title="struct serde::de::value::StringDeserializer">StringDeserializer</a>&lt;E&gt;<span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;E: <a class="trait" href="trait.Error.html" title="trait serde::de::Error">Error</a>,</span></h3></section></summary><div class="impl-items"><section id="associatedtype.Error-5" class="associatedtype trait-impl has-srclink"><a href="#associatedtype.Error-5" class="anchor"></a><h4 class="code-header">type <a href="#associatedtype.Error" class="associatedtype">Error</a> = E</h4></section><section id="associatedtype.Variant-5" class="associatedtype trait-impl has-srclink"><a href="#associatedtype.Variant-5" class="anchor"></a><h4 class="code-header">type <a href="#associatedtype.Variant" class="associatedtype">Variant</a> = UnitOnly&lt;E&gt;</h4></section></div></details><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-EnumAccess%3C%27de%3E-for-U32Deserializer%3CE%3E" class="impl has-srclink"><a class="srclink rightside" href="../../src/serde/de/value.rs.html#373-386">source</a><a href="#impl-EnumAccess%3C%27de%3E-for-U32Deserializer%3CE%3E" class="anchor"></a><h3 class="code-header">impl&lt;'de, E&gt; <a class="trait" href="trait.EnumAccess.html" title="trait serde::de::EnumAccess">EnumAccess</a>&lt;'de&gt; for <a class="struct" href="value/struct.U32Deserializer.html" title="struct serde::de::value::U32Deserializer">U32Deserializer</a>&lt;E&gt;<span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;E: <a class="trait" href="trait.Error.html" title="trait serde::de::Error">Error</a>,</span></h3></section></summary><div class="impl-items"><section id="associatedtype.Error-6" class="associatedtype trait-impl has-srclink"><a href="#associatedtype.Error-6" class="anchor"></a><h4 class="code-header">type <a href="#associatedtype.Error" class="associatedtype">Error</a> = E</h4></section><section id="associatedtype.Variant-6" class="associatedtype trait-impl has-srclink"><a href="#associatedtype.Variant-6" class="anchor"></a><h4 class="code-header">type <a href="#associatedtype.Variant" class="associatedtype">Variant</a> = UnitOnly&lt;E&gt;</h4></section></div></details></div><script src="../../implementors/serde/de/trait.EnumAccess.js" async></script></section></div></main><div id="rustdoc-vars" data-root-path="../../" data-current-crate="serde" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html>