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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="github crates-io docs-rs"><title>quote - Rust</title><script>if(window.location.protocol!=="file:")document.head.insertAdjacentHTML("beforeend","SourceSerif4-Regular-46f98efaafac5295.ttf.woff2,FiraSans-Regular-018c141bf0843ffd.woff2,FiraSans-Medium-8f9a781e4970d388.woff2,SourceCodePro-Regular-562dcc5011b6de7d.ttf.woff2,SourceCodePro-Semibold-d899c5a5c4aeb14a.ttf.woff2".split(",").map(f=>`<link rel="preload" as="font" type="font/woff2" crossorigin href="../static.files/${f}">`).join(""))</script><link rel="stylesheet" href="../static.files/normalize-76eba96aa4d2e634.css"><link rel="stylesheet" href="../static.files/rustdoc-dd39b87e5fcfba68.css"><meta name="rustdoc-vars" data-root-path="../" data-static-root-path="../static.files/" data-current-crate="quote" data-themes="" data-resource-suffix="" data-rustdoc-version="1.80.0 (051478957 2024-07-21)" data-channel="1.80.0" data-search-js="search-d52510db62a78183.js" data-settings-js="settings-4313503d2e1961c2.js" ><script src="../static.files/storage-118b08c4c78b968e.js"></script><script defer src="../crates.js"></script><script defer src="../static.files/main-20a3ad099b048cf2.js"></script><noscript><link rel="stylesheet" href="../static.files/noscript-df360f571f6edeae.css"></noscript><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 mod crate"><!--[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" title="show sidebar"></button></nav><nav class="sidebar"><div class="sidebar-crate"><h2><a href="../quote/index.html">quote</a><span class="version">1.0.36</span></h2></div><div class="sidebar-elems"><ul class="block"><li><a id="all-types" href="all.html">All Items</a></li></ul><section><ul class="block"><li><a href="#macros">Macros</a></li><li><a href="#traits">Traits</a></li></ul></section></div></nav><div class="sidebar-resizer"></div><main><div class="width-limiter"><rustdoc-search></rustdoc-search><section id="main-content" class="content"><div class="main-heading"><h1>Crate <a class="mod" href="#">quote</a><button id="copy-path" title="Copy item path to clipboard">Copy item path</button></h1><span class="out-of-band"><a class="src" href="../src/quote/lib.rs.html#1-1464">source</a> · <button id="toggle-all-docs" title="collapse all docs">[<span>−</span>]</button></span></div><details class="toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p><a href="https://github.com/dtolnay/quote"><img src="https://img.shields.io/badge/github-8da0cb?style=for-the-badge&labelColor=555555&logo=github" alt="github" /></a> <a href="https://crates.io/crates/quote"><img src="https://img.shields.io/badge/crates.io-fc8d62?style=for-the-badge&labelColor=555555&logo=rust" alt="crates-io" /></a> <a href="https://docs.rs/quote"><img src="https://img.shields.io/badge/docs.rs-66c2a5?style=for-the-badge&labelColor=555555&logo=docs.rs" alt="docs-rs" /></a></p>
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<br>
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<p>This crate provides the <a href="macro.quote.html"><code>quote!</code></a> macro for turning Rust syntax tree data
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structures into tokens of source code.</p>
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<p>Procedural macros in Rust receive a stream of tokens as input, execute
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arbitrary Rust code to determine how to manipulate those tokens, and produce
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a stream of tokens to hand back to the compiler to compile into the caller’s
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crate. Quasi-quoting is a solution to one piece of that — producing
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tokens to return to the compiler.</p>
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<p>The idea of quasi-quoting is that we write <em>code</em> that we treat as <em>data</em>.
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Within the <code>quote!</code> macro, we can write what looks like code to our text
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editor or IDE. We get all the benefits of the editor’s brace matching,
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syntax highlighting, indentation, and maybe autocompletion. But rather than
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compiling that as code into the current crate, we can treat it as data, pass
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it around, mutate it, and eventually hand it back to the compiler as tokens
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to compile into the macro caller’s crate.</p>
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<p>This crate is motivated by the procedural macro use case, but is a
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general-purpose Rust quasi-quoting library and is not specific to procedural
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macros.</p>
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<div class="example-wrap"><pre class="language-toml"><code>[dependencies]
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quote = "1.0"
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</code></pre></div><br>
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<h2 id="example"><a class="doc-anchor" href="#example">§</a>Example</h2>
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<p>The following quasi-quoted block of code is something you might find in <a href="https://serde.rs/">a</a>
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procedural macro having to do with data structure serialization. The <code>#var</code>
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syntax performs interpolation of runtime variables into the quoted tokens.
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Check out the documentation of the <a href="macro.quote.html"><code>quote!</code></a> macro for more detail about
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the syntax. See also the <a href="macro.quote_spanned.html"><code>quote_spanned!</code></a> macro which is important for
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implementing hygienic procedural macros.</p>
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<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">let </span>tokens = <span class="macro">quote!</span> {
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<span class="kw">struct </span>SerializeWith #generics #where_clause {
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value: <span class="kw-2">&</span><span class="lifetime">'a </span>#field_ty,
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phantom: core::marker::PhantomData<#item_ty>,
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}
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<span class="kw">impl </span>#generics serde::Serialize <span class="kw">for </span>SerializeWith #generics #where_clause {
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<span class="kw">fn </span>serialize<S>(<span class="kw-2">&</span><span class="self">self</span>, serializer: S) -> <span class="prelude-ty">Result</span><S::Ok, S::Error>
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<span class="kw">where
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</span>S: serde::Serializer,
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{
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#path(<span class="self">self</span>.value, serializer)
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}
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}
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SerializeWith {
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value: #value,
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phantom: core::marker::PhantomData::<#item_ty>,
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}
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};</code></pre></div>
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<br>
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<h2 id="non-macro-code-generators"><a class="doc-anchor" href="#non-macro-code-generators">§</a>Non-macro code generators</h2>
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<p>When using <code>quote</code> in a build.rs or main.rs and writing the output out to a
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file, consider having the code generator pass the tokens through
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<a href="https://github.com/dtolnay/prettyplease">prettyplease</a> before writing. This way if an error occurs in the generated
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code it is convenient for a human to read and debug.</p>
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</div></details><h2 id="macros" class="section-header">Macros<a href="#macros" class="anchor">§</a></h2><ul class="item-table"><li><div class="item-name"><a class="macro" href="macro.format_ident.html" title="macro quote::format_ident">format_ident</a></div><div class="desc docblock-short">Formatting macro for constructing <code>Ident</code>s.</div></li><li><div class="item-name"><a class="macro" href="macro.quote.html" title="macro quote::quote">quote</a></div><div class="desc docblock-short">The whole point.</div></li><li><div class="item-name"><a class="macro" href="macro.quote_spanned.html" title="macro quote::quote_spanned">quote_spanned</a></div><div class="desc docblock-short">Same as <code>quote!</code>, but applies a given span to all tokens originating within
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the macro invocation.</div></li></ul><h2 id="traits" class="section-header">Traits<a href="#traits" class="anchor">§</a></h2><ul class="item-table"><li><div class="item-name"><a class="trait" href="trait.IdentFragment.html" title="trait quote::IdentFragment">IdentFragment</a></div><div class="desc docblock-short">Specialized formatting trait used by <code>format_ident!</code>.</div></li><li><div class="item-name"><a class="trait" href="trait.ToTokens.html" title="trait quote::ToTokens">ToTokens</a></div><div class="desc docblock-short">Types that can be interpolated inside a <code>quote!</code> invocation.</div></li><li><div class="item-name"><a class="trait" href="trait.TokenStreamExt.html" title="trait quote::TokenStreamExt">TokenStreamExt</a></div><div class="desc docblock-short">TokenStream extension trait with methods for appending tokens.</div></li></ul></section></div></main></body></html> |