| <!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="Quasi-quotation macro that accepts input like the `quote!` macro but uses type inference to figure out a return type for those tokens."><meta name="keywords" content="rust, rustlang, rust-lang, parse_quote"><title>parse_quote 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 macro"><!--[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><div class="sidebar-elems"><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">Macro <a href="index.html">syn</a>::<wbr><a class="macro" href="#">parse_quote</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/parse_quote.rs.html#69-73">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"><div class="example-wrap"><pre class="rust macro"><code><span class="macro">macro_rules! </span>parse_quote { |
| ($(<span class="macro-nonterminal">$tt</span>:tt)<span class="kw-2">*</span>) => { ... }; |
| }</code></pre></div> |
| </div><details class="rustdoc-toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Quasi-quotation macro that accepts input like the <a href="https://docs.rs/quote/1.0/quote/index.html"><code>quote!</code></a> macro but uses |
| type inference to figure out a return type for those tokens.</p> |
| <p>The return type can be any syntax tree node that implements the <a href="parse/trait.Parse.html"><code>Parse</code></a> |
| trait.</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>quote::quote; |
| <span class="kw">use </span>syn::{parse_quote, Stmt}; |
| |
| <span class="kw">fn </span>main() { |
| <span class="kw">let </span>name = <span class="macro">quote!</span>(v); |
| <span class="kw">let </span>ty = <span class="macro">quote!</span>(u8); |
| |
| <span class="kw">let </span>stmt: Stmt = <span class="macro">parse_quote! </span>{ |
| <span class="kw">let </span>#name: #ty = Default::default(); |
| }; |
| |
| <span class="macro">println!</span>(<span class="string">"{:#?}"</span>, stmt); |
| }</code></pre></div> |
| <p><em>This macro is available only if Syn is built with both the <code>"parsing"</code> and |
| <code>"printing"</code> features.</em></p> |
| <h2 id="example"><a href="#example">Example</a></h2> |
| <p>The following helper function adds a bound <code>T: HeapSize</code> to every type |
| parameter <code>T</code> in the input generics.</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>syn::{parse_quote, Generics, GenericParam}; |
| |
| <span class="comment">// Add a bound `T: HeapSize` to every type parameter T. |
| </span><span class="kw">fn </span>add_trait_bounds(<span class="kw-2">mut </span>generics: Generics) -> Generics { |
| <span class="kw">for </span>param <span class="kw">in </span><span class="kw-2">&mut </span>generics.params { |
| <span class="kw">if let </span>GenericParam::Type(type_param) = param { |
| type_param.bounds.push(<span class="macro">parse_quote!</span>(HeapSize)); |
| } |
| } |
| generics |
| }</code></pre></div> |
| <h2 id="special-cases"><a href="#special-cases">Special cases</a></h2> |
| <p>This macro can parse the following additional types as a special case even |
| though they do not implement the <code>Parse</code> trait.</p> |
| <ul> |
| <li><a href="struct.Attribute.html" title="Attribute"><code>Attribute</code></a> — parses one attribute, allowing either outer like <code>#[...]</code> |
| or inner like <code>#![...]</code></li> |
| <li><a href="punctuated/struct.Punctuated.html" title="Punctuated<T, P>"><code>Punctuated<T, P></code></a> — parses zero or more <code>T</code> separated by punctuation |
| <code>P</code> with optional trailing punctuation</li> |
| <li><a href="struct.Block.html#method.parse_within"><code>Vec<Stmt></code></a> — parses the same as <code>Block::parse_within</code></li> |
| </ul> |
| <h2 id="panics"><a href="#panics">Panics</a></h2> |
| <p>Panics if the tokens fail to parse as the expected syntax tree type. The |
| caller is responsible for ensuring that the input tokens are syntactically |
| valid.</p> |
| </div></details></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> |
