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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 > < 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 >
< p > This crate provides the < a href = "macro.quote.html" > < code > quote!< / code > < / a > macro for turning Rust syntax tree data
structures into tokens of source code.< / p >
< p > Procedural macros in Rust receive a stream of tokens as input, execute
arbitrary Rust code to determine how to manipulate those tokens, and produce
a stream of tokens to hand back to the compiler to compile into the caller’
crate. Quasi-quoting is a solution to one piece of that — producing
tokens to return to the compiler.< / p >
< p > The idea of quasi-quoting is that we write < em > code< / em > that we treat as < em > data< / em > .
Within the < code > quote!< / code > macro, we can write what looks like code to our text
editor or IDE. We get all the benefits of the editor’
syntax highlighting, indentation, and maybe autocompletion. But rather than
compiling that as code into the current crate, we can treat it as data, pass
it around, mutate it, and eventually hand it back to the compiler as tokens
to compile into the macro caller’ < / p >
< p > This crate is motivated by the procedural macro use case, but is a
general-purpose Rust quasi-quoting library and is not specific to procedural
macros.< / p >
< div class = "example-wrap" > < pre class = "language-toml" > < code > [dependencies]
quote = " 1.0"
< / 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 >
procedural macro having to do with data structure serialization. The < code > #var< / code >
syntax performs interpolation of runtime variables into the quoted tokens.
Check out the documentation of the < a href = "macro.quote.html" > < code > quote!< / code > < / a > macro for more detail about
the syntax. See also the < a href = "macro.quote_spanned.html" > < code > quote_spanned!< / code > < / a > macro which is important for
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 {
value: < span class = "kw-2" > & < / span > < span class = "lifetime" > 'a < / span > #field_ty,
phantom: core::marker::PhantomData< #item_ty> ,
}
< span class = "kw" > impl < / span > #generics serde::Serialize < span class = "kw" > for < / span > SerializeWith #generics #where_clause {
< 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>
< span class = "kw" > where
< / span > S: serde::Serializer,
{
#path(< span class = "self" > self< / span > .value, serializer)
}
}
SerializeWith {
value: #value,
phantom: core::marker::PhantomData::< #item_ty> ,
}
};< / code > < / pre > < / div >
< 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
file, consider having the code generator pass the tokens through
< a href = "https://github.com/dtolnay/prettyplease" > prettyplease< / a > before writing. This way if an error occurs in the generated
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
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 >
