<!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="Source of the Rust file `/home/runner/.cargo/registry/src/index.crates.io-6f17d22bba15001f/quote-1.0.38/src/format.rs`."><title>format.rs - source</title><script>if(window.location.protocol!=="file:")document.head.insertAdjacentHTML("beforeend","SourceSerif4-Regular-6b053e98.ttf.woff2,FiraSans-Regular-0fe48ade.woff2,FiraSans-Medium-e1aa3f0a.woff2,SourceCodePro-Regular-8badfe75.ttf.woff2,SourceCodePro-Semibold-aa29a496.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-9960930a.css"><link rel="stylesheet" href="../../static.files/rustdoc-42caa33d.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="1.84.0 (9fc6b4312 2025-01-07)" data-channel="1.84.0" data-search-js="search-92e6798f.js" data-settings-js="settings-0f613d39.js" ><script src="../../static.files/storage-59e33391.js"></script><script defer src="../../static.files/src-script-56102188.js"></script><script defer src="../../src-files.js"></script><script defer src="../../static.files/main-5f194d8c.js"></script><noscript><link rel="stylesheet" href="../../static.files/noscript-893ab5e7.css"></noscript><link rel="alternate icon" type="image/png" href="../../static.files/favicon-32x32-6580c154.png"><link rel="icon" type="image/svg+xml" href="../../static.files/favicon-044be391.svg"></head><body class="rustdoc src"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><div class="src-sidebar-title"><h2>Files</h2></div></nav><div class="sidebar-resizer"></div><main><rustdoc-search></rustdoc-search><section id="main-content" class="content"><div class="main-heading"><h1><div class="sub-heading">quote/</div>format.rs</h1><rustdoc-toolbar></rustdoc-toolbar></div><div class="example-wrap"><div data-nosnippet><pre class="src-line-numbers">
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///
/// &lt;br&gt;
///
/// # Syntax
///
/// Syntax is copied from the [`format!`] macro, supporting both positional and
/// named arguments.
///
/// Only a limited set of formatting traits are supported. The current mapping
/// of format types to traits is:
///
/// * `{}` ⇒ [`IdentFragment`]
/// * `{:o}` ⇒ [`Octal`](std::fmt::Octal)
/// * `{:x}` ⇒ [`LowerHex`](std::fmt::LowerHex)
/// * `{:X}` ⇒ [`UpperHex`](std::fmt::UpperHex)
/// * `{:b}` ⇒ [`Binary`](std::fmt::Binary)
///
/// See [`std::fmt`] for more information.
///
/// &lt;br&gt;
///
/// # IdentFragment
///
/// Unlike `format!`, this macro uses the [`IdentFragment`] formatting trait by
/// default. This trait is like `Display`, with a few differences:
///
/// * `IdentFragment` is only implemented for a limited set of types, such as
///    unsigned integers and strings.
/// * [`Ident`] arguments will have their `r#` prefixes stripped, if present.
///
/// [`IdentFragment`]: crate::IdentFragment
/// [`Ident`]: proc_macro2::Ident
///
/// &lt;br&gt;
///
/// # Hygiene
///
/// The [`Span`] of the first `Ident` argument is used as the span of the final
/// identifier, falling back to [`Span::call_site`] when no identifiers are
/// provided.
///
/// ```
/// # use quote::format_ident;
/// # let ident = format_ident!("Ident");
/// // If `ident` is an Ident, the span of `my_ident` will be inherited from it.
/// let my_ident = format_ident!("My{}{}", ident, "IsCool");
/// assert_eq!(my_ident, "MyIdentIsCool");
/// ```
///
/// Alternatively, the span can be overridden by passing the `span` named
/// argument.
///
/// ```
/// # use quote::format_ident;
/// # const IGNORE_TOKENS: &amp;'static str = stringify! {
/// let my_span = /* ... */;
/// # };
/// # let my_span = proc_macro2::Span::call_site();
/// format_ident!("MyIdent", span = my_span);
/// ```
///
/// [`Span`]: proc_macro2::Span
/// [`Span::call_site`]: proc_macro2::Span::call_site
///
/// &lt;p&gt;&lt;br&gt;&lt;/p&gt;
///
/// # Panics
///
/// This method will panic if the resulting formatted string is not a valid
/// identifier.
///
/// &lt;br&gt;
///
/// # Examples
///
/// Composing raw and non-raw identifiers:
/// ```
/// # use quote::format_ident;
/// let my_ident = format_ident!("My{}", "Ident");
/// assert_eq!(my_ident, "MyIdent");
///
/// let raw = format_ident!("r#Raw");
/// assert_eq!(raw, "r#Raw");
///
/// let my_ident_raw = format_ident!("{}Is{}", my_ident, raw);
/// assert_eq!(my_ident_raw, "MyIdentIsRaw");
/// ```
///
/// Integer formatting options:
/// ```
/// # use quote::format_ident;
/// let num: u32 = 10;
///
/// let decimal = format_ident!("Id_{}", num);
/// assert_eq!(decimal, "Id_10");
///
/// let octal = format_ident!("Id_{:o}", num);
/// assert_eq!(octal, "Id_12");
///
/// let binary = format_ident!("Id_{:b}", num);
/// assert_eq!(binary, "Id_1010");
///
/// let lower_hex = format_ident!("Id_{:x}", num);
/// assert_eq!(lower_hex, "Id_a");
///
/// let upper_hex = format_ident!("Id_{:X}", num);
/// assert_eq!(upper_hex, "Id_A");
/// ```
</span><span class="attr">#[macro_export]
</span><span class="macro">macro_rules!</span> format_ident {
    (<span class="macro-nonterminal">$fmt</span>:expr) =&gt; {
        <span class="macro-nonterminal">$</span><span class="macro">crate::format_ident_impl!</span>([
            <span class="macro-nonterminal">$crate::__private::Option::None</span>,
            <span class="macro-nonterminal">$fmt
        </span>])
    };

    (<span class="macro-nonterminal">$fmt</span>:expr, $(<span class="macro-nonterminal">$rest</span>:tt)<span class="kw-2">*</span>) =&gt; {
        <span class="macro-nonterminal">$</span><span class="macro">crate::format_ident_impl!</span>([
            <span class="macro-nonterminal">$crate::__private::Option::None</span>,
            <span class="macro-nonterminal">$fmt
        </span>] $(<span class="macro-nonterminal">$rest</span>)<span class="kw-2">*</span>)
    };
}

<span class="attr">#[macro_export]
#[doc(hidden)]
</span><span class="macro">macro_rules!</span> format_ident_impl {
    <span class="comment">// Final state
    </span>([<span class="macro-nonterminal">$span</span>:expr, $(<span class="macro-nonterminal">$fmt</span>:tt)<span class="kw-2">*</span>]) =&gt; {
        <span class="macro-nonterminal">$crate::__private::mk_ident</span>(
            <span class="kw-2">&amp;</span><span class="macro-nonterminal">$</span><span class="macro">crate::__private::format!</span>($(<span class="macro-nonterminal">$fmt</span>)<span class="kw-2">*</span>),
            <span class="macro-nonterminal">$span</span>,
        )
    };

    <span class="comment">// Span argument
    </span>([<span class="macro-nonterminal">$old</span>:expr, $(<span class="macro-nonterminal">$fmt</span>:tt)<span class="kw-2">*</span>] span = <span class="macro-nonterminal">$span</span>:expr) =&gt; {
        <span class="macro-nonterminal">$</span><span class="macro">crate::format_ident_impl!</span>([<span class="macro-nonterminal">$old</span>, $(<span class="macro-nonterminal">$fmt</span>)<span class="kw-2">*</span>] span = <span class="macro-nonterminal">$span</span>,)
    };
    ([<span class="macro-nonterminal">$old</span>:expr, $(<span class="macro-nonterminal">$fmt</span>:tt)<span class="kw-2">*</span>] span = <span class="macro-nonterminal">$span</span>:expr, $(<span class="macro-nonterminal">$rest</span>:tt)<span class="kw-2">*</span>) =&gt; {
        <span class="macro-nonterminal">$</span><span class="macro">crate::format_ident_impl!</span>([
            <span class="macro-nonterminal">$crate::__private::Option::Some</span>::&lt;<span class="macro-nonterminal">$crate::__private::Span</span>&gt;(<span class="macro-nonterminal">$span</span>),
            $(<span class="macro-nonterminal">$fmt</span>)*
        ] $(<span class="macro-nonterminal">$rest</span>)<span class="kw-2">*</span>)
    };

    <span class="comment">// Named argument
    </span>([<span class="macro-nonterminal">$span</span>:expr, $(<span class="macro-nonterminal">$fmt</span>:tt)<span class="kw-2">*</span>] <span class="macro-nonterminal">$name</span>:ident = <span class="macro-nonterminal">$arg</span>:expr) =&gt; {
        <span class="macro-nonterminal">$</span><span class="macro">crate::format_ident_impl!</span>([<span class="macro-nonterminal">$span</span>, $(<span class="macro-nonterminal">$fmt</span>)<span class="kw-2">*</span>] <span class="macro-nonterminal">$name </span>= <span class="macro-nonterminal">$arg</span>,)
    };
    ([<span class="macro-nonterminal">$span</span>:expr, $(<span class="macro-nonterminal">$fmt</span>:tt)<span class="kw-2">*</span>] <span class="macro-nonterminal">$name</span>:ident = <span class="macro-nonterminal">$arg</span>:expr, $(<span class="macro-nonterminal">$rest</span>:tt)<span class="kw-2">*</span>) =&gt; {
        <span class="kw">match </span><span class="macro-nonterminal">$crate::__private::IdentFragmentAdapter</span>(<span class="kw-2">&amp;</span><span class="macro-nonterminal">$arg</span>) {
            arg =&gt; <span class="macro-nonterminal">$</span><span class="macro">crate::format_ident_impl!</span>([<span class="macro-nonterminal">$span</span>.or(arg.span()), $(<span class="macro-nonterminal">$fmt</span>)<span class="kw-2">*</span>, <span class="macro-nonterminal">$name </span>= arg] $(<span class="macro-nonterminal">$rest</span>)<span class="kw-2">*</span>),
        }
    };

    <span class="comment">// Positional argument
    </span>([<span class="macro-nonterminal">$span</span>:expr, $(<span class="macro-nonterminal">$fmt</span>:tt)<span class="kw-2">*</span>] <span class="macro-nonterminal">$arg</span>:expr) =&gt; {
        <span class="macro-nonterminal">$</span><span class="macro">crate::format_ident_impl!</span>([<span class="macro-nonterminal">$span</span>, $(<span class="macro-nonterminal">$fmt</span>)<span class="kw-2">*</span>] <span class="macro-nonterminal">$arg</span>,)
    };
    ([<span class="macro-nonterminal">$span</span>:expr, $(<span class="macro-nonterminal">$fmt</span>:tt)<span class="kw-2">*</span>] <span class="macro-nonterminal">$arg</span>:expr, $(<span class="macro-nonterminal">$rest</span>:tt)<span class="kw-2">*</span>) =&gt; {
        <span class="kw">match </span><span class="macro-nonterminal">$crate::__private::IdentFragmentAdapter</span>(<span class="kw-2">&amp;</span><span class="macro-nonterminal">$arg</span>) {
            arg =&gt; <span class="macro-nonterminal">$</span><span class="macro">crate::format_ident_impl!</span>([<span class="macro-nonterminal">$span</span>.or(arg.span()), $(<span class="macro-nonterminal">$fmt</span>)<span class="kw-2">*</span>, arg] $(<span class="macro-nonterminal">$rest</span>)<span class="kw-2">*</span>),
        }
    };
}
</code></pre></div></section></main></body></html>