| <!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="An attribute, like `#[repr(transparent)]`."><meta name="keywords" content="rust, rustlang, rust-lang, Attribute"><title>Attribute in syn - 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 struct"><!--[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><a class="sidebar-logo" href="../syn/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="../syn/index.html"><div class="logo-container"><img class="rust-logo" src="../rust-logo.svg" alt="logo"></div></a><h2 class="location"><a href="#">Attribute</a></h2><div class="sidebar-elems"><section><h3><a href="#fields">Fields</a></h3><ul class="block"><li><a href="#structfield.bracket_token">bracket_token</a></li><li><a href="#structfield.meta">meta</a></li><li><a href="#structfield.pound_token">pound_token</a></li><li><a href="#structfield.style">style</a></li></ul><h3><a href="#implementations">Methods</a></h3><ul class="block"><li><a href="#method.parse_args">parse_args</a></li><li><a href="#method.parse_args_with">parse_args_with</a></li><li><a href="#method.parse_inner">parse_inner</a></li><li><a href="#method.parse_nested_meta">parse_nested_meta</a></li><li><a href="#method.parse_outer">parse_outer</a></li><li><a href="#method.path">path</a></li></ul><h3><a href="#trait-implementations">Trait Implementations</a></h3><ul class="block"><li><a href="#impl-Clone-for-Attribute">Clone</a></li><li><a href="#impl-Debug-for-Attribute">Debug</a></li><li><a href="#impl-Eq-for-Attribute">Eq</a></li><li><a href="#impl-Hash-for-Attribute">Hash</a></li><li><a href="#impl-PartialEq%3CAttribute%3E-for-Attribute">PartialEq<Attribute></a></li><li><a href="#impl-ToTokens-for-Attribute">ToTokens</a></li></ul><h3><a href="#synthetic-implementations">Auto Trait Implementations</a></h3><ul class="block"><li><a href="#impl-RefUnwindSafe-for-Attribute">RefUnwindSafe</a></li><li><a href="#impl-Send-for-Attribute">!Send</a></li><li><a href="#impl-Sync-for-Attribute">!Sync</a></li><li><a href="#impl-Unpin-for-Attribute">Unpin</a></li><li><a href="#impl-UnwindSafe-for-Attribute">UnwindSafe</a></li></ul><h3><a href="#blanket-implementations">Blanket Implementations</a></h3><ul class="block"><li><a href="#impl-Any-for-Attribute">Any</a></li><li><a href="#impl-Borrow%3CT%3E-for-Attribute">Borrow<T></a></li><li><a href="#impl-BorrowMut%3CT%3E-for-Attribute">BorrowMut<T></a></li><li><a href="#impl-From%3CT%3E-for-Attribute">From<T></a></li><li><a href="#impl-Into%3CU%3E-for-Attribute">Into<U></a></li><li><a href="#impl-Spanned-for-Attribute">Spanned</a></li><li><a href="#impl-ToOwned-for-Attribute">ToOwned</a></li><li><a href="#impl-TryFrom%3CU%3E-for-Attribute">TryFrom<U></a></li><li><a href="#impl-TryInto%3CU%3E-for-Attribute">TryInto<U></a></li></ul></section><h2><a href="index.html">In syn</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">Struct <a href="index.html">syn</a>::<wbr><a class="struct" href="#">Attribute</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/syn/attr.rs.html#11-171">source</a> · <a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs">[<span class="inner">−</span>]</a></span></div><div class="item-decl"><pre class="rust struct"><code>pub struct Attribute { |
| pub pound_token: <a class="struct" href="token/struct.Pound.html" title="struct syn::token::Pound">Pound</a>, |
| pub style: <a class="enum" href="enum.AttrStyle.html" title="enum syn::AttrStyle">AttrStyle</a>, |
| pub bracket_token: <a class="struct" href="token/struct.Bracket.html" title="struct syn::token::Bracket">Bracket</a>, |
| pub meta: <a class="enum" href="enum.Meta.html" title="enum syn::Meta">Meta</a>, |
| }</code></pre></div><details class="rustdoc-toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>An attribute, like <code>#[repr(transparent)]</code>.</p> |
| <br> |
| <h2 id="syntax"><a href="#syntax">Syntax</a></h2> |
| <p>Rust has six types of attributes.</p> |
| <ul> |
| <li> |
| <p>Outer attributes like <code>#[repr(transparent)]</code>. These appear outside or |
| in front of the item they describe.</p> |
| </li> |
| <li> |
| <p>Inner attributes like <code>#![feature(proc_macro)]</code>. These appear inside |
| of the item they describe, usually a module.</p> |
| </li> |
| <li> |
| <p>Outer one-line doc comments like <code>/// Example</code>.</p> |
| </li> |
| <li> |
| <p>Inner one-line doc comments like <code>//! Please file an issue</code>.</p> |
| </li> |
| <li> |
| <p>Outer documentation blocks <code>/** Example */</code>.</p> |
| </li> |
| <li> |
| <p>Inner documentation blocks <code>/*! Please file an issue */</code>.</p> |
| </li> |
| </ul> |
| <p>The <code>style</code> field of type <code>AttrStyle</code> distinguishes whether an attribute |
| is outer or inner.</p> |
| <p>Every attribute has a <code>path</code> that indicates the intended interpretation |
| of the rest of the attribute’s contents. The path and the optional |
| additional contents are represented together in the <code>meta</code> field of the |
| attribute in three possible varieties:</p> |
| <ul> |
| <li> |
| <p>Meta::Path — attributes whose information content conveys just a |
| path, for example the <code>#[test]</code> attribute.</p> |
| </li> |
| <li> |
| <p>Meta::List — attributes that carry arbitrary tokens after the |
| path, surrounded by a delimiter (parenthesis, bracket, or brace). For |
| example <code>#[derive(Copy)]</code> or <code>#[precondition(x < 5)]</code>.</p> |
| </li> |
| <li> |
| <p>Meta::NameValue — attributes with an <code>=</code> sign after the path, |
| followed by a Rust expression. For example <code>#[path = "sys/windows.rs"]</code>.</p> |
| </li> |
| </ul> |
| <p>All doc comments are represented in the NameValue style with a path of |
| “doc”, as this is how they are processed by the compiler and by |
| <code>macro_rules!</code> macros.</p> |
| <div class="example-wrap"><pre class="language-text"><code>#[derive(Copy, Clone)] |
| ~~~~~~Path |
| ^^^^^^^^^^^^^^^^^^^Meta::List |
| |
| #[path = "sys/windows.rs"] |
| ~~~~Path |
| ^^^^^^^^^^^^^^^^^^^^^^^Meta::NameValue |
| |
| #[test] |
| ^^^^Meta::Path</code></pre></div><br> |
| <h2 id="parsing-from-tokens-to-attribute"><a href="#parsing-from-tokens-to-attribute">Parsing from tokens to Attribute</a></h2> |
| <p>This type does not implement the <a href="parse/trait.Parse.html"><code>Parse</code></a> trait and thus cannot be |
| parsed directly by <a href="parse/struct.ParseBuffer.html#method.parse"><code>ParseStream::parse</code></a>. Instead use |
| <a href="parse/struct.ParseBuffer.html#method.call"><code>ParseStream::call</code></a> with one of the two parser functions |
| <a href="struct.Attribute.html#method.parse_outer" title="Attribute::parse_outer"><code>Attribute::parse_outer</code></a> or <a href="struct.Attribute.html#method.parse_inner" title="Attribute::parse_inner"><code>Attribute::parse_inner</code></a> depending on |
| which you intend to parse.</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>syn::{Attribute, Ident, <span class="prelude-ty">Result</span>, Token}; |
| <span class="kw">use </span>syn::parse::{Parse, ParseStream}; |
| |
| <span class="comment">// Parses a unit struct with attributes. |
| // |
| // #[path = "s.tmpl"] |
| // struct S; |
| </span><span class="kw">struct </span>UnitStruct { |
| attrs: Vec<Attribute>, |
| struct_token: <span class="macro">Token!</span>[<span class="kw">struct</span>], |
| name: Ident, |
| semi_token: <span class="macro">Token!</span>[;], |
| } |
| |
| <span class="kw">impl </span>Parse <span class="kw">for </span>UnitStruct { |
| <span class="kw">fn </span>parse(input: ParseStream) -> <span class="prelude-ty">Result</span><<span class="self">Self</span>> { |
| <span class="prelude-val">Ok</span>(UnitStruct { |
| attrs: input.call(Attribute::parse_outer)<span class="question-mark">?</span>, |
| struct_token: input.parse()<span class="question-mark">?</span>, |
| name: input.parse()<span class="question-mark">?</span>, |
| semi_token: input.parse()<span class="question-mark">?</span>, |
| }) |
| } |
| }</code></pre></div> |
| <p><br></p> |
| <h2 id="parsing-from-attribute-to-structured-arguments"><a href="#parsing-from-attribute-to-structured-arguments">Parsing from Attribute to structured arguments</a></h2> |
| <p>The grammar of attributes in Rust is very flexible, which makes the |
| syntax tree not that useful on its own. In particular, arguments of the |
| <code>Meta::List</code> variety of attribute are held in an arbitrary <code>tokens: TokenStream</code>. Macros are expected to check the <code>path</code> of the attribute, |
| decide whether they recognize it, and then parse the remaining tokens |
| according to whatever grammar they wish to require for that kind of |
| attribute. Use <a href="struct.Attribute.html#method.parse_args"><code>parse_args()</code></a> to parse those tokens into the expected |
| data structure.</p> |
| <p><br></p> |
| <h2 id="doc-comments"><a href="#doc-comments">Doc comments</a></h2> |
| <p>The compiler transforms doc comments, such as <code>/// comment</code> and <code>/*! comment */</code>, into attributes before macros are expanded. Each comment is |
| expanded into an attribute of the form <code>#[doc = r"comment"]</code>.</p> |
| <p>As an example, the following <code>mod</code> items are expanded identically:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">let </span>doc: ItemMod = <span class="macro">parse_quote! </span>{ |
| <span class="doccomment">/// Single line doc comments |
| /// We write so many! |
| /** |
| * Multi-line comments... |
| * May span many lines |
| */ |
| </span><span class="kw">mod </span>example { |
| <span class="doccomment">//! Of course, they can be inner too |
| /*! And fit in a single line */ |
| </span>} |
| }; |
| <span class="kw">let </span>attr: ItemMod = <span class="macro">parse_quote! </span>{ |
| <span class="attribute">#[doc = <span class="string">r" Single line doc comments"</span>] |
| #[doc = <span class="string">r" We write so many!"</span>] |
| #[doc = <span class="string">r" |
| * Multi-line comments... |
| * May span many lines |
| "</span>] |
| </span><span class="kw">mod </span>example { |
| <span class="attribute">#![doc = <span class="string">r" Of course, they can be inner too"</span>] |
| #![doc = <span class="string">r" And fit in a single line "</span>] |
| </span>} |
| }; |
| <span class="macro">assert_eq!</span>(doc, attr);</code></pre></div> |
| </div></details><h2 id="fields" class="fields small-section-header">Fields<a href="#fields" class="anchor"></a></h2><span id="structfield.pound_token" class="structfield small-section-header"><a href="#structfield.pound_token" class="anchor field"></a><code>pound_token: <a class="struct" href="token/struct.Pound.html" title="struct syn::token::Pound">Pound</a></code></span><span id="structfield.style" class="structfield small-section-header"><a href="#structfield.style" class="anchor field"></a><code>style: <a class="enum" href="enum.AttrStyle.html" title="enum syn::AttrStyle">AttrStyle</a></code></span><span id="structfield.bracket_token" class="structfield small-section-header"><a href="#structfield.bracket_token" class="anchor field"></a><code>bracket_token: <a class="struct" href="token/struct.Bracket.html" title="struct syn::token::Bracket">Bracket</a></code></span><span id="structfield.meta" class="structfield small-section-header"><a href="#structfield.meta" class="anchor field"></a><code>meta: <a class="enum" href="enum.Meta.html" title="enum syn::Meta">Meta</a></code></span><h2 id="implementations" class="small-section-header">Implementations<a href="#implementations" class="anchor"></a></h2><div id="implementations-list"><details class="rustdoc-toggle implementors-toggle" open><summary><section id="impl-Attribute" class="impl has-srclink"><a class="srclink rightside" href="../src/syn/attr.rs.html#173-419">source</a><a href="#impl-Attribute" class="anchor"></a><h3 class="code-header">impl <a class="struct" href="struct.Attribute.html" title="struct syn::Attribute">Attribute</a></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle method-toggle" open><summary><section id="method.path" class="method has-srclink"><a class="srclink rightside" href="../src/syn/attr.rs.html#178-180">source</a><h4 class="code-header">pub fn <a href="#method.path" class="fnname">path</a>(&self) -> &<a class="struct" href="struct.Path.html" title="struct syn::Path">Path</a></h4></section></summary><div class="docblock"><p>Returns the path that identifies the interpretation of this attribute.</p> |
| <p>For example this would return the <code>test</code> in <code>#[test]</code>, the <code>derive</code> in |
| <code>#[derive(Copy)]</code>, and the <code>path</code> in <code>#[path = "sys/windows.rs"]</code>.</p> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.parse_args" class="method has-srclink"><a class="srclink rightside" href="../src/syn/attr.rs.html#214-216">source</a><h4 class="code-header">pub fn <a href="#method.parse_args" class="fnname">parse_args</a><T: <a class="trait" href="parse/trait.Parse.html" title="trait syn::parse::Parse">Parse</a>>(&self) -> <a class="type" href="parse/type.Result.html" title="type syn::parse::Result">Result</a><T></h4></section></summary><div class="docblock"><p>Parse the arguments to the attribute as a syntax tree.</p> |
| <p>This is similar to pulling out the <code>TokenStream</code> from <code>Meta::List</code> and |
| doing <code>syn::parse2::<T>(meta_list.tokens)</code>, except that using |
| <code>parse_args</code> the error message has a more useful span when <code>tokens</code> is |
| empty.</p> |
| <p>The surrounding delimiters are <em>not</em> included in the input to the |
| parser.</p> |
| <div class="example-wrap"><pre class="language-text"><code>#[my_attr(value < 5)] |
| ^^^^^^^^^ what gets parsed</code></pre></div><h5 id="example"><a href="#example">Example</a></h5> |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>syn::{parse_quote, Attribute, Expr}; |
| |
| <span class="kw">let </span>attr: Attribute = <span class="macro">parse_quote! </span>{ |
| <span class="attribute">#[precondition(value < <span class="number">5</span>)] |
| </span>}; |
| |
| <span class="kw">if </span>attr.path().is_ident(<span class="string">"precondition"</span>) { |
| <span class="kw">let </span>precondition: Expr = attr.parse_args()<span class="question-mark">?</span>; |
| <span class="comment">// ... |
| </span>}</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.parse_args_with" class="method has-srclink"><a class="srclink rightside" href="../src/syn/attr.rs.html#237-258">source</a><h4 class="code-header">pub fn <a href="#method.parse_args_with" class="fnname">parse_args_with</a><F: <a class="trait" href="parse/trait.Parser.html" title="trait syn::parse::Parser">Parser</a>>(&self, parser: F) -> <a class="type" href="parse/type.Result.html" title="type syn::parse::Result">Result</a><F::<a class="associatedtype" href="parse/trait.Parser.html#associatedtype.Output" title="type syn::parse::Parser::Output">Output</a>></h4></section></summary><div class="docblock"><p>Parse the arguments to the attribute using the given parser.</p> |
| <h5 id="example-1"><a href="#example-1">Example</a></h5> |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>syn::{parse_quote, Attribute}; |
| |
| <span class="kw">let </span>attr: Attribute = <span class="macro">parse_quote! </span>{ |
| <span class="attribute">#[inception { <span class="attribute">#[brrrrrrraaaaawwwwrwrrrmrmrmmrmrmmmmm] </span>}] |
| }; |
| |
| <span class="kw">let </span>bwom = attr.parse_args_with(Attribute::parse_outer)<span class="question-mark">?</span>; |
| |
| <span class="comment">// Attribute does not have a Parse impl, so we couldn't directly do: |
| // let bwom: Attribute = attr.parse_args()?;</span></code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.parse_nested_meta" class="method has-srclink"><a class="srclink rightside" href="../src/syn/attr.rs.html#383-388">source</a><h4 class="code-header">pub fn <a href="#method.parse_nested_meta" class="fnname">parse_nested_meta</a>(<br> &self,<br> logic: impl <a class="trait" href="https://doc.rust-lang.org/nightly/core/ops/function/trait.FnMut.html" title="trait core::ops::function::FnMut">FnMut</a>(<a class="struct" href="meta/struct.ParseNestedMeta.html" title="struct syn::meta::ParseNestedMeta">ParseNestedMeta</a><'_>) -> <a class="type" href="parse/type.Result.html" title="type syn::parse::Result">Result</a><<a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.unit.html">()</a>><br>) -> <a class="type" href="parse/type.Result.html" title="type syn::parse::Result">Result</a><<a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.unit.html">()</a>></h4></section></summary><div class="docblock"><p>Parse the arguments to the attribute, expecting it to follow the |
| conventional structure used by most of Rust’s built-in attributes.</p> |
| <p>The <a href="https://doc.rust-lang.org/reference/attributes.html#meta-item-attribute-syntax"><em>Meta Item Attribute Syntax</em></a> section in the Rust reference |
| explains the convention in more detail. Not all attributes follow this |
| convention, so <a href="struct.Attribute.html#method.parse_args" title="Self::parse_args"><code>parse_args()</code></a> is available if you |
| need to parse arbitrarily goofy attribute syntax.</p> |
| <h5 id="example-2"><a href="#example-2">Example</a></h5> |
| <p>We’ll parse a struct, and then parse some of Rust’s <code>#[repr]</code> attribute |
| syntax.</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>syn::{parenthesized, parse_quote, token, ItemStruct, LitInt}; |
| |
| <span class="kw">let </span>input: ItemStruct = <span class="macro">parse_quote! </span>{ |
| <span class="attribute">#[repr(C, align(<span class="number">4</span>))] |
| </span><span class="kw">pub struct </span>MyStruct(u16, u32); |
| }; |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>repr_c = <span class="bool-val">false</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>repr_transparent = <span class="bool-val">false</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>repr_align = <span class="prelude-val">None</span>::<usize>; |
| <span class="kw">let </span><span class="kw-2">mut </span>repr_packed = <span class="prelude-val">None</span>::<usize>; |
| <span class="kw">for </span>attr <span class="kw">in </span><span class="kw-2">&</span>input.attrs { |
| <span class="kw">if </span>attr.path().is_ident(<span class="string">"repr"</span>) { |
| attr.parse_nested_meta(|meta| { |
| <span class="comment">// #[repr(C)] |
| </span><span class="kw">if </span>meta.path.is_ident(<span class="string">"C"</span>) { |
| repr_c = <span class="bool-val">true</span>; |
| <span class="kw">return </span><span class="prelude-val">Ok</span>(()); |
| } |
| |
| <span class="comment">// #[repr(transparent)] |
| </span><span class="kw">if </span>meta.path.is_ident(<span class="string">"transparent"</span>) { |
| repr_transparent = <span class="bool-val">true</span>; |
| <span class="kw">return </span><span class="prelude-val">Ok</span>(()); |
| } |
| |
| <span class="comment">// #[repr(align(N))] |
| </span><span class="kw">if </span>meta.path.is_ident(<span class="string">"align"</span>) { |
| <span class="kw">let </span>content; |
| <span class="macro">parenthesized!</span>(content <span class="kw">in </span>meta.input); |
| <span class="kw">let </span>lit: LitInt = content.parse()<span class="question-mark">?</span>; |
| <span class="kw">let </span>n: usize = lit.base10_parse()<span class="question-mark">?</span>; |
| repr_align = <span class="prelude-val">Some</span>(n); |
| <span class="kw">return </span><span class="prelude-val">Ok</span>(()); |
| } |
| |
| <span class="comment">// #[repr(packed)] or #[repr(packed(N))], omitted N means 1 |
| </span><span class="kw">if </span>meta.path.is_ident(<span class="string">"packed"</span>) { |
| <span class="kw">if </span>meta.input.peek(token::Paren) { |
| <span class="kw">let </span>content; |
| <span class="macro">parenthesized!</span>(content <span class="kw">in </span>meta.input); |
| <span class="kw">let </span>lit: LitInt = content.parse()<span class="question-mark">?</span>; |
| <span class="kw">let </span>n: usize = lit.base10_parse()<span class="question-mark">?</span>; |
| repr_packed = <span class="prelude-val">Some</span>(n); |
| } <span class="kw">else </span>{ |
| repr_packed = <span class="prelude-val">Some</span>(<span class="number">1</span>); |
| } |
| <span class="kw">return </span><span class="prelude-val">Ok</span>(()); |
| } |
| |
| <span class="prelude-val">Err</span>(meta.error(<span class="string">"unrecognized repr"</span>)) |
| })<span class="question-mark">?</span>; |
| } |
| }</code></pre></div> |
| <h5 id="alternatives"><a href="#alternatives">Alternatives</a></h5> |
| <p>In some cases, for attributes which have nested layers of structured |
| content, the following less flexible approach might be more convenient:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>syn::punctuated::Punctuated; |
| <span class="kw">use </span>syn::{parenthesized, token, Error, LitInt, Meta, Token}; |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>repr_c = <span class="bool-val">false</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>repr_transparent = <span class="bool-val">false</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>repr_align = <span class="prelude-val">None</span>::<usize>; |
| <span class="kw">let </span><span class="kw-2">mut </span>repr_packed = <span class="prelude-val">None</span>::<usize>; |
| <span class="kw">for </span>attr <span class="kw">in </span><span class="kw-2">&</span>input.attrs { |
| <span class="kw">if </span>attr.path().is_ident(<span class="string">"repr"</span>) { |
| <span class="kw">let </span>nested = attr.parse_args_with(Punctuated::<Meta, <span class="macro">Token!</span>[,]>::parse_terminated)<span class="question-mark">?</span>; |
| <span class="kw">for </span>meta <span class="kw">in </span>nested { |
| <span class="kw">match </span>meta { |
| <span class="comment">// #[repr(C)] |
| </span>Meta::Path(path) <span class="kw">if </span>path.is_ident(<span class="string">"C"</span>) => { |
| repr_c = <span class="bool-val">true</span>; |
| } |
| |
| <span class="comment">// #[repr(align(N))] |
| </span>Meta::List(meta) <span class="kw">if </span>meta.path.is_ident(<span class="string">"align"</span>) => { |
| <span class="kw">let </span>lit: LitInt = meta.parse_args()<span class="question-mark">?</span>; |
| <span class="kw">let </span>n: usize = lit.base10_parse()<span class="question-mark">?</span>; |
| repr_align = <span class="prelude-val">Some</span>(n); |
| } |
| |
| <span class="comment">/* ... */ |
| |
| </span><span class="kw">_ </span>=> { |
| <span class="kw">return </span><span class="prelude-val">Err</span>(Error::new_spanned(meta, <span class="string">"unrecognized repr"</span>)); |
| } |
| } |
| } |
| } |
| }</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.parse_outer" class="method has-srclink"><a class="srclink rightside" href="../src/syn/attr.rs.html#398-404">source</a><h4 class="code-header">pub fn <a href="#method.parse_outer" class="fnname">parse_outer</a>(input: <a class="type" href="parse/type.ParseStream.html" title="type syn::parse::ParseStream">ParseStream</a><'_>) -> <a class="type" href="parse/type.Result.html" title="type syn::parse::Result">Result</a><<a class="struct" href="https://doc.rust-lang.org/nightly/alloc/vec/struct.Vec.html" title="struct alloc::vec::Vec">Vec</a><Self>></h4></section></summary><div class="docblock"><p>Parses zero or more outer attributes from the stream.</p> |
| <h5 id="example-3"><a href="#example-3">Example</a></h5> |
| <p>See |
| <a href="#parsing-from-tokens-to-attribute"><em>Parsing from tokens to Attribute</em></a>.</p> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.parse_inner" class="method has-srclink"><a class="srclink rightside" href="../src/syn/attr.rs.html#414-418">source</a><h4 class="code-header">pub fn <a href="#method.parse_inner" class="fnname">parse_inner</a>(input: <a class="type" href="parse/type.ParseStream.html" title="type syn::parse::ParseStream">ParseStream</a><'_>) -> <a class="type" href="parse/type.Result.html" title="type syn::parse::Result">Result</a><<a class="struct" href="https://doc.rust-lang.org/nightly/alloc/vec/struct.Vec.html" title="struct alloc::vec::Vec">Vec</a><Self>></h4></section></summary><div class="docblock"><p>Parses zero or more inner attributes from the stream.</p> |
| <h5 id="example-4"><a href="#example-4">Example</a></h5> |
| <p>See |
| <a href="#parsing-from-tokens-to-attribute"><em>Parsing from tokens to Attribute</em></a>.</p> |
| </div></details></div></details></div><h2 id="trait-implementations" class="small-section-header">Trait Implementations<a href="#trait-implementations" class="anchor"></a></h2><div id="trait-implementations-list"><details class="rustdoc-toggle implementors-toggle" open><summary><section id="impl-Clone-for-Attribute" class="impl has-srclink"><a class="srclink rightside" href="../src/syn/gen/clone.rs.html#78-87">source</a><a href="#impl-Clone-for-Attribute" class="anchor"></a><h3 class="code-header">impl <a class="trait" href="https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a> for <a class="struct" href="struct.Attribute.html" title="struct syn::Attribute">Attribute</a></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle method-toggle" open><summary><section id="method.clone" class="method trait-impl has-srclink"><a class="srclink rightside" href="../src/syn/gen/clone.rs.html#79-86">source</a><a href="#method.clone" class="anchor"></a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html#tymethod.clone" class="fnname">clone</a>(&self) -> Self</h4></section></summary><div class='docblock'>Returns a copy of the value. <a href="https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html#tymethod.clone">Read more</a></div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.clone_from" class="method trait-impl has-srclink"><span class="rightside"><span class="since" title="Stable since Rust version 1.0.0">1.0.0</span> · <a class="srclink" href="https://doc.rust-lang.org/nightly/src/core/clone.rs.html#132-134">source</a></span><a href="#method.clone_from" class="anchor"></a><h4 class="code-header">const fn <a href="https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html#method.clone_from" class="fnname">clone_from</a>(&mut self, source: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&</a>Self)</h4></section></summary><div class='docblock'>Performs copy-assignment from <code>source</code>. <a href="https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html#method.clone_from">Read more</a></div></details></div></details><details class="rustdoc-toggle implementors-toggle" open><summary><section id="impl-Debug-for-Attribute" class="impl has-srclink"><a class="srclink rightside" href="../src/syn/gen/debug.rs.html#88-97">source</a><a href="#impl-Debug-for-Attribute" class="anchor"></a><h3 class="code-header">impl <a class="trait" href="https://doc.rust-lang.org/nightly/core/fmt/trait.Debug.html" title="trait core::fmt::Debug">Debug</a> for <a class="struct" href="struct.Attribute.html" title="struct syn::Attribute">Attribute</a></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle method-toggle" open><summary><section id="method.fmt" class="method trait-impl has-srclink"><a class="srclink rightside" href="../src/syn/gen/debug.rs.html#89-96">source</a><a href="#method.fmt" class="anchor"></a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/nightly/core/fmt/trait.Debug.html#tymethod.fmt" class="fnname">fmt</a>(&self, formatter: &mut <a class="struct" href="https://doc.rust-lang.org/nightly/core/fmt/struct.Formatter.html" title="struct core::fmt::Formatter">Formatter</a><'_>) -> <a class="type" href="https://doc.rust-lang.org/nightly/core/fmt/type.Result.html" title="type core::fmt::Result">Result</a></h4></section></summary><div class='docblock'>Formats the value using the given formatter. <a href="https://doc.rust-lang.org/nightly/core/fmt/trait.Debug.html#tymethod.fmt">Read more</a></div></details></div></details><details class="rustdoc-toggle implementors-toggle" open><summary><section id="impl-Hash-for-Attribute" class="impl has-srclink"><a class="srclink rightside" href="../src/syn/gen/hash.rs.html#86-94">source</a><a href="#impl-Hash-for-Attribute" class="anchor"></a><h3 class="code-header">impl <a class="trait" href="https://doc.rust-lang.org/nightly/core/hash/trait.Hash.html" title="trait core::hash::Hash">Hash</a> for <a class="struct" href="struct.Attribute.html" title="struct syn::Attribute">Attribute</a></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle method-toggle" open><summary><section id="method.hash" class="method trait-impl has-srclink"><a class="srclink rightside" href="../src/syn/gen/hash.rs.html#87-93">source</a><a href="#method.hash" class="anchor"></a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/nightly/core/hash/trait.Hash.html#tymethod.hash" class="fnname">hash</a><H>(&self, state: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&mut </a>H)<span class="where fmt-newline">where<br> H: <a class="trait" href="https://doc.rust-lang.org/nightly/core/hash/trait.Hasher.html" title="trait core::hash::Hasher">Hasher</a>,</span></h4></section></summary><div class='docblock'>Feeds this value into the given <a href="https://doc.rust-lang.org/nightly/core/hash/trait.Hasher.html" title="Hasher"><code>Hasher</code></a>. <a href="https://doc.rust-lang.org/nightly/core/hash/trait.Hash.html#tymethod.hash">Read more</a></div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.hash_slice" class="method trait-impl has-srclink"><span class="rightside"><span class="since" title="Stable since Rust version 1.3.0">1.3.0</span> · <a class="srclink" href="https://doc.rust-lang.org/nightly/src/core/hash/mod.rs.html#237-239">source</a></span><a href="#method.hash_slice" class="anchor"></a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/nightly/core/hash/trait.Hash.html#method.hash_slice" class="fnname">hash_slice</a><H>(data: &<a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.slice.html">[Self]</a>, state: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&mut </a>H)<span class="where fmt-newline">where<br> H: <a class="trait" href="https://doc.rust-lang.org/nightly/core/hash/trait.Hasher.html" title="trait core::hash::Hasher">Hasher</a>,</span></h4></section></summary><div class='docblock'>Feeds a slice of this type into the given <a href="https://doc.rust-lang.org/nightly/core/hash/trait.Hasher.html" title="Hasher"><code>Hasher</code></a>. <a href="https://doc.rust-lang.org/nightly/core/hash/trait.Hash.html#method.hash_slice">Read more</a></div></details></div></details><details class="rustdoc-toggle implementors-toggle" open><summary><section id="impl-PartialEq%3CAttribute%3E-for-Attribute" class="impl has-srclink"><a class="srclink rightside" href="../src/syn/gen/eq.rs.html#79-83">source</a><a href="#impl-PartialEq%3CAttribute%3E-for-Attribute" class="anchor"></a><h3 class="code-header">impl <a class="trait" href="https://doc.rust-lang.org/nightly/core/cmp/trait.PartialEq.html" title="trait core::cmp::PartialEq">PartialEq</a><<a class="struct" href="struct.Attribute.html" title="struct syn::Attribute">Attribute</a>> for <a class="struct" href="struct.Attribute.html" title="struct syn::Attribute">Attribute</a></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle method-toggle" open><summary><section id="method.eq" class="method trait-impl has-srclink"><a class="srclink rightside" href="../src/syn/gen/eq.rs.html#80-82">source</a><a href="#method.eq" class="anchor"></a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/nightly/core/cmp/trait.PartialEq.html#tymethod.eq" class="fnname">eq</a>(&self, other: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&</a>Self) -> <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.bool.html">bool</a></h4></section></summary><div class='docblock'>This method tests for <code>self</code> and <code>other</code> values to be equal, and is used |
| by <code>==</code>. <a href="https://doc.rust-lang.org/nightly/core/cmp/trait.PartialEq.html#tymethod.eq">Read more</a></div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.ne" class="method trait-impl has-srclink"><span class="rightside"><span class="since" title="Stable since Rust version 1.0.0">1.0.0</span> · <a class="srclink" href="https://doc.rust-lang.org/nightly/src/core/cmp.rs.html#227">source</a></span><a href="#method.ne" class="anchor"></a><h4 class="code-header">const fn <a href="https://doc.rust-lang.org/nightly/core/cmp/trait.PartialEq.html#method.ne" class="fnname">ne</a>(&self, other: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&</a>Rhs) -> <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.bool.html">bool</a></h4></section></summary><div class='docblock'>This method tests for <code>!=</code>. The default implementation is almost always |
| sufficient, and should not be overridden without very good reason. <a href="https://doc.rust-lang.org/nightly/core/cmp/trait.PartialEq.html#method.ne">Read more</a></div></details></div></details><details class="rustdoc-toggle implementors-toggle" open><summary><section id="impl-ToTokens-for-Attribute" class="impl has-srclink"><a class="srclink rightside" href="../src/syn/attr.rs.html#748-758">source</a><a href="#impl-ToTokens-for-Attribute" class="anchor"></a><h3 class="code-header">impl <a class="trait" href="../quote/to_tokens/trait.ToTokens.html" title="trait quote::to_tokens::ToTokens">ToTokens</a> for <a class="struct" href="struct.Attribute.html" title="struct syn::Attribute">Attribute</a></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle method-toggle" open><summary><section id="method.to_tokens" class="method trait-impl has-srclink"><a class="srclink rightside" href="../src/syn/attr.rs.html#749-757">source</a><a href="#method.to_tokens" class="anchor"></a><h4 class="code-header">fn <a href="../quote/to_tokens/trait.ToTokens.html#tymethod.to_tokens" class="fnname">to_tokens</a>(&self, tokens: &mut <a class="struct" href="../proc_macro2/struct.TokenStream.html" title="struct proc_macro2::TokenStream">TokenStream</a>)</h4></section></summary><div class='docblock'>Write <code>self</code> to the given <code>TokenStream</code>. <a href="../quote/to_tokens/trait.ToTokens.html#tymethod.to_tokens">Read more</a></div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.to_token_stream" class="method trait-impl has-srclink"><a class="srclink rightside" href="../src/quote/to_tokens.rs.html#59">source</a><a href="#method.to_token_stream" class="anchor"></a><h4 class="code-header">fn <a href="../quote/to_tokens/trait.ToTokens.html#method.to_token_stream" class="fnname">to_token_stream</a>(&self) -> <a class="struct" href="../proc_macro2/struct.TokenStream.html" title="struct proc_macro2::TokenStream">TokenStream</a></h4></section></summary><div class='docblock'>Convert <code>self</code> directly into a <code>TokenStream</code> object. <a href="../quote/to_tokens/trait.ToTokens.html#method.to_token_stream">Read more</a></div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.into_token_stream" class="method trait-impl has-srclink"><a class="srclink rightside" href="../src/quote/to_tokens.rs.html#69-71">source</a><a href="#method.into_token_stream" class="anchor"></a><h4 class="code-header">fn <a href="../quote/to_tokens/trait.ToTokens.html#method.into_token_stream" class="fnname">into_token_stream</a>(self) -> <a class="struct" href="../proc_macro2/struct.TokenStream.html" title="struct proc_macro2::TokenStream">TokenStream</a></h4></section></summary><div class='docblock'>Convert <code>self</code> directly into a <code>TokenStream</code> object. <a href="../quote/to_tokens/trait.ToTokens.html#method.into_token_stream">Read more</a></div></details></div></details><section id="impl-Eq-for-Attribute" class="impl has-srclink"><a class="srclink rightside" href="../src/syn/gen/eq.rs.html#76">source</a><a href="#impl-Eq-for-Attribute" class="anchor"></a><h3 class="code-header">impl <a class="trait" href="https://doc.rust-lang.org/nightly/core/cmp/trait.Eq.html" title="trait core::cmp::Eq">Eq</a> for <a class="struct" href="struct.Attribute.html" title="struct syn::Attribute">Attribute</a></h3></section></div><h2 id="synthetic-implementations" class="small-section-header">Auto Trait Implementations<a href="#synthetic-implementations" class="anchor"></a></h2><div id="synthetic-implementations-list"><section id="impl-RefUnwindSafe-for-Attribute" class="impl has-srclink"><a href="#impl-RefUnwindSafe-for-Attribute" class="anchor"></a><h3 class="code-header">impl <a class="trait" href="https://doc.rust-lang.org/nightly/core/panic/unwind_safe/trait.RefUnwindSafe.html" title="trait core::panic::unwind_safe::RefUnwindSafe">RefUnwindSafe</a> for <a class="struct" href="struct.Attribute.html" title="struct syn::Attribute">Attribute</a></h3></section><section id="impl-Send-for-Attribute" class="impl has-srclink"><a href="#impl-Send-for-Attribute" class="anchor"></a><h3 class="code-header">impl !<a class="trait" href="https://doc.rust-lang.org/nightly/core/marker/trait.Send.html" title="trait core::marker::Send">Send</a> for <a class="struct" href="struct.Attribute.html" title="struct syn::Attribute">Attribute</a></h3></section><section id="impl-Sync-for-Attribute" class="impl has-srclink"><a href="#impl-Sync-for-Attribute" class="anchor"></a><h3 class="code-header">impl !<a class="trait" href="https://doc.rust-lang.org/nightly/core/marker/trait.Sync.html" title="trait core::marker::Sync">Sync</a> for <a class="struct" href="struct.Attribute.html" title="struct syn::Attribute">Attribute</a></h3></section><section id="impl-Unpin-for-Attribute" class="impl has-srclink"><a href="#impl-Unpin-for-Attribute" class="anchor"></a><h3 class="code-header">impl <a class="trait" href="https://doc.rust-lang.org/nightly/core/marker/trait.Unpin.html" title="trait core::marker::Unpin">Unpin</a> for <a class="struct" href="struct.Attribute.html" title="struct syn::Attribute">Attribute</a></h3></section><section id="impl-UnwindSafe-for-Attribute" class="impl has-srclink"><a href="#impl-UnwindSafe-for-Attribute" class="anchor"></a><h3 class="code-header">impl <a class="trait" href="https://doc.rust-lang.org/nightly/core/panic/unwind_safe/trait.UnwindSafe.html" title="trait core::panic::unwind_safe::UnwindSafe">UnwindSafe</a> for <a class="struct" href="struct.Attribute.html" title="struct syn::Attribute">Attribute</a></h3></section></div><h2 id="blanket-implementations" class="small-section-header">Blanket Implementations<a href="#blanket-implementations" class="anchor"></a></h2><div id="blanket-implementations-list"><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-Any-for-Attribute" class="impl has-srclink"><a class="srclink rightside" href="https://doc.rust-lang.org/nightly/src/core/any.rs.html#200">source</a><a href="#impl-Any-for-Attribute" class="anchor"></a><h3 class="code-header">impl<T> <a class="trait" href="https://doc.rust-lang.org/nightly/core/any/trait.Any.html" title="trait core::any::Any">Any</a> for T<span class="where fmt-newline">where<br> T: 'static + ?<a class="trait" href="https://doc.rust-lang.org/nightly/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a>,</span></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle method-toggle" open><summary><section id="method.type_id" class="method trait-impl has-srclink"><a class="srclink rightside" href="https://doc.rust-lang.org/nightly/src/core/any.rs.html#201">source</a><a href="#method.type_id" class="anchor"></a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/nightly/core/any/trait.Any.html#tymethod.type_id" class="fnname">type_id</a>(&self) -> <a class="struct" href="https://doc.rust-lang.org/nightly/core/any/struct.TypeId.html" title="struct core::any::TypeId">TypeId</a></h4></section></summary><div class='docblock'>Gets the <code>TypeId</code> of <code>self</code>. <a href="https://doc.rust-lang.org/nightly/core/any/trait.Any.html#tymethod.type_id">Read more</a></div></details></div></details><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-Borrow%3CT%3E-for-Attribute" class="impl has-srclink"><a class="srclink rightside" href="https://doc.rust-lang.org/nightly/src/core/borrow.rs.html#211">source</a><a href="#impl-Borrow%3CT%3E-for-Attribute" class="anchor"></a><h3 class="code-header">impl<T> <a class="trait" href="https://doc.rust-lang.org/nightly/core/borrow/trait.Borrow.html" title="trait core::borrow::Borrow">Borrow</a><T> for T<span class="where fmt-newline">where<br> T: ?<a class="trait" href="https://doc.rust-lang.org/nightly/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a>,</span></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle method-toggle" open><summary><section id="method.borrow" class="method trait-impl has-srclink"><span class="rightside"><span class="since" title="const unstable">const: <a href="https://github.com/rust-lang/rust/issues/91522" title="Tracking issue for const_borrow">unstable</a></span> · <a class="srclink" href="https://doc.rust-lang.org/nightly/src/core/borrow.rs.html#213">source</a></span><a href="#method.borrow" class="anchor"></a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/nightly/core/borrow/trait.Borrow.html#tymethod.borrow" class="fnname">borrow</a>(&self) -> <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&</a>T</h4></section></summary><div class='docblock'>Immutably borrows from an owned value. <a href="https://doc.rust-lang.org/nightly/core/borrow/trait.Borrow.html#tymethod.borrow">Read more</a></div></details></div></details><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-BorrowMut%3CT%3E-for-Attribute" class="impl has-srclink"><a class="srclink rightside" href="https://doc.rust-lang.org/nightly/src/core/borrow.rs.html#220">source</a><a href="#impl-BorrowMut%3CT%3E-for-Attribute" class="anchor"></a><h3 class="code-header">impl<T> <a class="trait" href="https://doc.rust-lang.org/nightly/core/borrow/trait.BorrowMut.html" title="trait core::borrow::BorrowMut">BorrowMut</a><T> for T<span class="where fmt-newline">where<br> T: ?<a class="trait" href="https://doc.rust-lang.org/nightly/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a>,</span></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle method-toggle" open><summary><section id="method.borrow_mut" class="method trait-impl has-srclink"><span class="rightside"><span class="since" title="const unstable">const: <a href="https://github.com/rust-lang/rust/issues/91522" title="Tracking issue for const_borrow">unstable</a></span> · <a class="srclink" href="https://doc.rust-lang.org/nightly/src/core/borrow.rs.html#221">source</a></span><a href="#method.borrow_mut" class="anchor"></a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/nightly/core/borrow/trait.BorrowMut.html#tymethod.borrow_mut" class="fnname">borrow_mut</a>(&mut self) -> <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&mut </a>T</h4></section></summary><div class='docblock'>Mutably borrows from an owned value. <a href="https://doc.rust-lang.org/nightly/core/borrow/trait.BorrowMut.html#tymethod.borrow_mut">Read more</a></div></details></div></details><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-From%3CT%3E-for-Attribute" class="impl has-srclink"><a class="srclink rightside" href="https://doc.rust-lang.org/nightly/src/core/convert/mod.rs.html#733">source</a><a href="#impl-From%3CT%3E-for-Attribute" class="anchor"></a><h3 class="code-header">impl<T> <a class="trait" href="https://doc.rust-lang.org/nightly/core/convert/trait.From.html" title="trait core::convert::From">From</a><T> for T</h3></section></summary><div class="impl-items"><details class="rustdoc-toggle method-toggle" open><summary><section id="method.from" class="method trait-impl has-srclink"><span class="rightside"><span class="since" title="const unstable">const: <a href="https://github.com/rust-lang/rust/issues/88674" title="Tracking issue for const_convert">unstable</a></span> · <a class="srclink" href="https://doc.rust-lang.org/nightly/src/core/convert/mod.rs.html#736">source</a></span><a href="#method.from" class="anchor"></a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/nightly/core/convert/trait.From.html#tymethod.from" class="fnname">from</a>(t: T) -> T</h4></section></summary><div class="docblock"><p>Returns the argument unchanged.</p> |
| </div></details></div></details><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-Into%3CU%3E-for-Attribute" class="impl has-srclink"><a class="srclink rightside" href="https://doc.rust-lang.org/nightly/src/core/convert/mod.rs.html#717">source</a><a href="#impl-Into%3CU%3E-for-Attribute" class="anchor"></a><h3 class="code-header">impl<T, U> <a class="trait" href="https://doc.rust-lang.org/nightly/core/convert/trait.Into.html" title="trait core::convert::Into">Into</a><U> for T<span class="where fmt-newline">where<br> U: <a class="trait" href="https://doc.rust-lang.org/nightly/core/convert/trait.From.html" title="trait core::convert::From">From</a><T>,</span></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle method-toggle" open><summary><section id="method.into" class="method trait-impl has-srclink"><span class="rightside"><span class="since" title="const unstable">const: <a href="https://github.com/rust-lang/rust/issues/88674" title="Tracking issue for const_convert">unstable</a></span> · <a class="srclink" href="https://doc.rust-lang.org/nightly/src/core/convert/mod.rs.html#725">source</a></span><a href="#method.into" class="anchor"></a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/nightly/core/convert/trait.Into.html#tymethod.into" class="fnname">into</a>(self) -> U</h4></section></summary><div class="docblock"><p>Calls <code>U::from(self)</code>.</p> |
| <p>That is, this conversion is whatever the implementation of |
| <code><a href="https://doc.rust-lang.org/nightly/core/convert/trait.From.html" title="From">From</a><T> for U</code> chooses to do.</p> |
| </div></details></div></details><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-Spanned-for-Attribute" class="impl has-srclink"><a class="srclink rightside" href="../src/syn/spanned.rs.html#104-108">source</a><a href="#impl-Spanned-for-Attribute" class="anchor"></a><h3 class="code-header">impl<T> <a class="trait" href="spanned/trait.Spanned.html" title="trait syn::spanned::Spanned">Spanned</a> for T<span class="where fmt-newline">where<br> T: Spanned + ?<a class="trait" href="https://doc.rust-lang.org/nightly/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a>,</span></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle method-toggle" open><summary><section id="method.span" class="method trait-impl has-srclink"><a class="srclink rightside" href="../src/syn/spanned.rs.html#105-107">source</a><a href="#method.span" class="anchor"></a><h4 class="code-header">fn <a href="spanned/trait.Spanned.html#tymethod.span" class="fnname">span</a>(&self) -> <a class="struct" href="../proc_macro2/struct.Span.html" title="struct proc_macro2::Span">Span</a></h4></section></summary><div class='docblock'>Returns a <code>Span</code> covering the complete contents of this syntax tree |
| node, or <a href="../proc_macro2/struct.Span.html#method.call_site"><code>Span::call_site()</code></a> if this node is empty. <a href="spanned/trait.Spanned.html#tymethod.span">Read more</a></div></details></div></details><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-ToOwned-for-Attribute" class="impl has-srclink"><a class="srclink rightside" href="https://doc.rust-lang.org/nightly/src/alloc/borrow.rs.html#83">source</a><a href="#impl-ToOwned-for-Attribute" class="anchor"></a><h3 class="code-header">impl<T> <a class="trait" href="https://doc.rust-lang.org/nightly/alloc/borrow/trait.ToOwned.html" title="trait alloc::borrow::ToOwned">ToOwned</a> for T<span class="where fmt-newline">where<br> T: <a class="trait" href="https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>,</span></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle" open><summary><section id="associatedtype.Owned" class="associatedtype trait-impl has-srclink"><a href="#associatedtype.Owned" class="anchor"></a><h4 class="code-header">type <a href="https://doc.rust-lang.org/nightly/alloc/borrow/trait.ToOwned.html#associatedtype.Owned" class="associatedtype">Owned</a> = T</h4></section></summary><div class='docblock'>The resulting type after obtaining ownership.</div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.to_owned" class="method trait-impl has-srclink"><a class="srclink rightside" href="https://doc.rust-lang.org/nightly/src/alloc/borrow.rs.html#88">source</a><a href="#method.to_owned" class="anchor"></a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/nightly/alloc/borrow/trait.ToOwned.html#tymethod.to_owned" class="fnname">to_owned</a>(&self) -> T</h4></section></summary><div class='docblock'>Creates owned data from borrowed data, usually by cloning. <a href="https://doc.rust-lang.org/nightly/alloc/borrow/trait.ToOwned.html#tymethod.to_owned">Read more</a></div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.clone_into" class="method trait-impl has-srclink"><a class="srclink rightside" href="https://doc.rust-lang.org/nightly/src/alloc/borrow.rs.html#92">source</a><a href="#method.clone_into" class="anchor"></a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/nightly/alloc/borrow/trait.ToOwned.html#method.clone_into" class="fnname">clone_into</a>(&self, target: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&mut </a>T)</h4></section></summary><div class='docblock'>Uses borrowed data to replace owned data, usually by cloning. <a href="https://doc.rust-lang.org/nightly/alloc/borrow/trait.ToOwned.html#method.clone_into">Read more</a></div></details></div></details><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-TryFrom%3CU%3E-for-Attribute" class="impl has-srclink"><a class="srclink rightside" href="https://doc.rust-lang.org/nightly/src/core/convert/mod.rs.html#775">source</a><a href="#impl-TryFrom%3CU%3E-for-Attribute" class="anchor"></a><h3 class="code-header">impl<T, U> <a class="trait" href="https://doc.rust-lang.org/nightly/core/convert/trait.TryFrom.html" title="trait core::convert::TryFrom">TryFrom</a><U> for T<span class="where fmt-newline">where<br> U: <a class="trait" href="https://doc.rust-lang.org/nightly/core/convert/trait.Into.html" title="trait core::convert::Into">Into</a><T>,</span></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle" open><summary><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="https://doc.rust-lang.org/nightly/core/convert/trait.TryFrom.html#associatedtype.Error" class="associatedtype">Error</a> = <a class="enum" href="https://doc.rust-lang.org/nightly/core/convert/enum.Infallible.html" title="enum core::convert::Infallible">Infallible</a></h4></section></summary><div class='docblock'>The type returned in the event of a conversion error.</div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.try_from" class="method trait-impl has-srclink"><span class="rightside"><span class="since" title="const unstable">const: <a href="https://github.com/rust-lang/rust/issues/88674" title="Tracking issue for const_convert">unstable</a></span> · <a class="srclink" href="https://doc.rust-lang.org/nightly/src/core/convert/mod.rs.html#781">source</a></span><a href="#method.try_from" class="anchor"></a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/nightly/core/convert/trait.TryFrom.html#tymethod.try_from" class="fnname">try_from</a>(value: U) -> <a class="enum" href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html" title="enum core::result::Result">Result</a><T, <T as <a class="trait" href="https://doc.rust-lang.org/nightly/core/convert/trait.TryFrom.html" title="trait core::convert::TryFrom">TryFrom</a><U>>::<a class="associatedtype" href="https://doc.rust-lang.org/nightly/core/convert/trait.TryFrom.html#associatedtype.Error" title="type core::convert::TryFrom::Error">Error</a>></h4></section></summary><div class='docblock'>Performs the conversion.</div></details></div></details><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-TryInto%3CU%3E-for-Attribute" class="impl has-srclink"><a class="srclink rightside" href="https://doc.rust-lang.org/nightly/src/core/convert/mod.rs.html#760">source</a><a href="#impl-TryInto%3CU%3E-for-Attribute" class="anchor"></a><h3 class="code-header">impl<T, U> <a class="trait" href="https://doc.rust-lang.org/nightly/core/convert/trait.TryInto.html" title="trait core::convert::TryInto">TryInto</a><U> for T<span class="where fmt-newline">where<br> U: <a class="trait" href="https://doc.rust-lang.org/nightly/core/convert/trait.TryFrom.html" title="trait core::convert::TryFrom">TryFrom</a><T>,</span></h3></section></summary><div class="impl-items"><details class="rustdoc-toggle" open><summary><section id="associatedtype.Error" class="associatedtype trait-impl has-srclink"><a href="#associatedtype.Error" class="anchor"></a><h4 class="code-header">type <a href="https://doc.rust-lang.org/nightly/core/convert/trait.TryInto.html#associatedtype.Error" class="associatedtype">Error</a> = <U as <a class="trait" href="https://doc.rust-lang.org/nightly/core/convert/trait.TryFrom.html" title="trait core::convert::TryFrom">TryFrom</a><T>>::<a class="associatedtype" href="https://doc.rust-lang.org/nightly/core/convert/trait.TryFrom.html#associatedtype.Error" title="type core::convert::TryFrom::Error">Error</a></h4></section></summary><div class='docblock'>The type returned in the event of a conversion error.</div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.try_into" class="method trait-impl has-srclink"><span class="rightside"><span class="since" title="const unstable">const: <a href="https://github.com/rust-lang/rust/issues/88674" title="Tracking issue for const_convert">unstable</a></span> · <a class="srclink" href="https://doc.rust-lang.org/nightly/src/core/convert/mod.rs.html#766">source</a></span><a href="#method.try_into" class="anchor"></a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/nightly/core/convert/trait.TryInto.html#tymethod.try_into" class="fnname">try_into</a>(self) -> <a class="enum" href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html" title="enum core::result::Result">Result</a><U, <U as <a class="trait" href="https://doc.rust-lang.org/nightly/core/convert/trait.TryFrom.html" title="trait core::convert::TryFrom">TryFrom</a><T>>::<a class="associatedtype" href="https://doc.rust-lang.org/nightly/core/convert/trait.TryFrom.html#associatedtype.Error" title="type core::convert::TryFrom::Error">Error</a>></h4></section></summary><div class='docblock'>Performs the conversion.</div></details></div></details></div></section></div></main><div id="rustdoc-vars" data-root-path="../" data-current-crate="syn" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
