38 lines
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38 lines
5.3 KiB
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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="Gets the value in the `Some` variant."><title>unwrap_some 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="#">unwrap_<wbr>some</a></h2><h3><a href="#">Sections</a></h3><ul class="block top-toc"><li><a href="#panics" title="Panics">Panics</a></li><li><a href="#example" title="Example">Example</a><ul><li><a href="#error" title="Error">Error</a></li></ul></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">unwrap_some</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/unwrapping.rs.html#51-60">Source</a> </span></div><pre class="rust item-decl"><code>macro_rules! unwrap_some {
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($opt: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>Gets the value in the <code>Some</code> variant.</p>
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<h2 id="panics"><a class="doc-anchor" href="#panics">§</a>Panics</h2>
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<p>Panics if <code>$opt</code> is a None.</p>
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<h2 id="example"><a class="doc-anchor" href="#example">§</a>Example</h2>
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<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>const_panic::unwrap_some;
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<span class="kw">const </span>SUM: u8 = <span class="macro">unwrap_some!</span>(add_up(<span class="kw-2">&</span>[<span class="number">3</span>, <span class="number">5</span>, <span class="number">8</span>, <span class="number">13</span>]));
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<span class="macro">assert_eq!</span>(SUM, <span class="number">29</span>);
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<span class="kw">const fn </span>add_up(<span class="kw-2">mut </span>slice: <span class="kw-2">&</span>[u8]) -> <span class="prelude-ty">Option</span><u8> {
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<span class="kw">let </span><span class="kw-2">mut </span>sum = <span class="number">0u8</span>;
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<span class="kw">while let </span>[x, <span class="kw-2">ref </span>rem @ ..] = <span class="kw-2">*</span>slice {
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<span class="kw">match </span>sum.checked_add(x) {
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<span class="prelude-val">Some</span>(x) => sum = x,
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<span class="prelude-val">None </span>=> <span class="kw">return </span><span class="prelude-val">None</span>,
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}
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slice = rem;
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}
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<span class="prelude-val">Some</span>(sum)
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}
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</code></pre></div>
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<h4 id="error"><a class="doc-anchor" href="#error">§</a>Error</h4>
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<p>This is what the compile-time error looks like when attempting to unwrap a <code>None</code>:</p>
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<div class="example-wrap"><pre class="language-text"><code>error[E0080]: evaluation of constant value failed
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--> src/macros/unwrapping.rs:10:17
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6 | const SUM: u8 = unwrap_some!(add_up(&[3, 5, 8, 13, 250]));
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked at '
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invoked `unwrap_some` macro with a `None` value', src/macros/unwrapping.rs:6:17
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= note: this error originates in the macro `unwrap_some` (in Nightly builds, run with -Z macro-backtrace for more info)
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</code></pre></div></div></details></section></div></main></body></html> |