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61 lines
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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="Coerces `$reff` to a type that has a `to_panicvals` method, which is expected to return a `[PanicVal<'_>; LEN]`."><title>coerce_fmt in const_panic - Rust</title><script>if(window.location.protocol!=="file:")document.head.insertAdjacentHTML("beforeend","SourceSerif4-Regular-6b053e98.ttf.woff2,FiraSans-Regular-0fe48ade.woff2,FiraSans-Medium-e1aa3f0a.woff2,SourceCodePro-Regular-8badfe75.ttf.woff2,SourceCodePro-Semibold-aa29a496.ttf.woff2".split(",").map(f=>`<link rel="preload" as="font" type="font/woff2" crossorigin href="../static.files/${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="const_panic" 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="sidebar-items.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 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" title="show sidebar"></button></nav><nav class="sidebar"><div class="sidebar-crate"><h2><a href="../const_panic/index.html">const_<wbr>panic</a><span class="version">0.2.10</span></h2></div><div class="sidebar-elems"><section id="rustdoc-toc"><h2 class="location"><a href="#">coerce_<wbr>fmt</a></h2><h3><a href="#">Sections</a></h3><ul class="block top-toc"><li><a href="#limitations" title="Limitations">Limitations</a></li><li><a href="#example" title="Example">Example</a></li></ul></section><div id="rustdoc-modnav"><h2 class="in-crate"><a href="index.html">In crate const_<wbr>panic</a></h2></div></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"><span class="rustdoc-breadcrumbs"><a href="index.html">const_panic</a></span><h1>Macro <span class="macro">coerce_fmt</span><button id="copy-path" title="Copy item path to clipboard">Copy item path</button></h1><rustdoc-toolbar></rustdoc-toolbar><span class="sub-heading"><a class="src" href="../src/const_panic/macros.rs.html#106-112">Source</a> </span></div><pre class="rust item-decl"><code>macro_rules! coerce_fmt {
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($reff:expr) => { ... };
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}</code></pre><details class="toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Coerces <code>$reff</code> to a type that has a <code>to_panicvals</code> method,
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which is expected to return a <code>[PanicVal<'_>; LEN]</code>.</p>
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<h2 id="limitations"><a class="doc-anchor" href="#limitations">§</a>Limitations</h2>
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<p>Arguments to the formatting/panicking macros must have a fully inferred concrete type,
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because <code>const_panic</code> macros use duck typing to call methods on those arguments.</p>
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<p>One effect of that limitation is that you will have to pass suffixed
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integer literals (eg: <code>100u8</code>) when those integers aren’t inferred to be a concrete type.</p>
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<h2 id="example"><a class="doc-anchor" href="#example">§</a>Example</h2>
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<p>This example uses <a href="crate::ArrayString"><code>const_panic::ArrayString</code></a>
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to show what the values format into,
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which requires the <code>"non_basic"</code> crate feature (enabled by default).</p>
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<div class="example-wrap ignore"><a href="#" class="tooltip" title="This example is not tested">ⓘ</a><pre class="rust rust-example-rendered"><code><span class="kw">use </span>const_panic::{ArrayString, FmtArg, IsCustomType, PanicFmt, PanicVal, coerce_fmt};
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<span class="kw">type </span>AS = ArrayString<<span class="number">100</span>>;
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<span class="macro">assert_eq!</span>(
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AS::from_panicvals(<span class="kw-2">&</span><span class="macro">coerce_fmt!</span>(<span class="number">100u8</span>).to_panicvals(FmtArg::DEBUG)).unwrap(),
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<span class="string">"100"</span>,
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);
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<span class="macro">assert_eq!</span>(
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AS::from_panicvals(<span class="kw-2">&</span><span class="macro">coerce_fmt!</span>(<span class="string">"hello\n"</span>).to_panicvals(FmtArg::DEBUG)).unwrap(),
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<span class="string">r#""hello\n""#</span>,
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);
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<span class="macro">assert_eq!</span>(
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AS::from_panicvals(<span class="kw-2">&</span><span class="macro">coerce_fmt!</span>(IsReal::No).to_panicvals(FmtArg::DEBUG)).unwrap(),
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<span class="string">"No"</span>,
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);
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<span class="macro">assert_eq!</span>(
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AS::from_panicvals(<span class="kw-2">&</span><span class="macro">coerce_fmt!</span>(IsReal::Yes).to_panicvals(FmtArg::DEBUG)).unwrap(),
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<span class="string">"Yes"</span>,
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);
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<span class="kw">enum </span>IsReal{Yes, No}
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<span class="comment">// All the code below manually implements panic formatting for a field-less enum.
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// This can be written concisely with the `PanicFmt` derive or `impl_panicfmt` macro.
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</span><span class="kw">impl </span>PanicFmt <span class="kw">for </span>IsReal {
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<span class="kw">type </span>This = <span class="self">Self</span>;
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<span class="kw">type </span>Kind = IsCustomType;
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<span class="kw">const </span>PV_COUNT: usize = <span class="number">1</span>;
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}
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<span class="kw">impl </span>IsReal {
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<span class="kw">pub const fn </span>to_panicvals(<span class="kw-2">&</span><span class="self">self</span>, _f: FmtArg) -> [PanicVal<<span class="lifetime">'_</span>>; IsReal::PV_COUNT] {
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<span class="kw">let </span>x = <span class="kw">match </span><span class="self">self </span>{
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<span class="self">Self</span>::Yes => <span class="string">"Yes"</span>,
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<span class="self">Self</span>::No => <span class="string">"No"</span>,
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};
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[PanicVal::write_str(x)]
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}
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}
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</code></pre></div>
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</div></details></section></div></main></body></html> |