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28 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="API documentation for the Rust `alt_complete` macro in crate `nom`."><meta name="keywords" content="rust, rustlang, rust-lang, alt_complete"><title>nom::alt_complete - Rust</title><link rel="stylesheet" type="text/css" href="../normalize.css"><link rel="stylesheet" type="text/css" href="../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" type="text/css" href="../dark.css"><link rel="stylesheet" type="text/css" href="../light.css" id="themeStyle"><script src="../storage.js"></script><noscript><link rel="stylesheet" href="../noscript.css"></noscript><link rel="shortcut icon" href="../favicon.ico"><style type="text/css">#crate-search{background-image:url("../down-arrow.svg");}</style></head><body class="rustdoc macro"><!--[if lte IE 8]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><div class="sidebar-menu">☰</div><a href='../nom/index.html'><div class='logo-container'><img src='../rust-logo.png' alt='logo'></div></a><div class="sidebar-elems"><p class='location'><a href='index.html'>nom</a></p><script>window.sidebarCurrent = {name: 'alt_complete', ty: 'macro', relpath: ''};</script><script defer src="sidebar-items.js"></script></div></nav><div class="theme-picker"><button id="theme-picker" aria-label="Pick another theme!"><img src="../brush.svg" width="18" alt="Pick another theme!"></button><div id="theme-choices"></div></div><script src="../theme.js"></script><nav class="sub"><form class="search-form"><div class="search-container"><div><select id="crate-search"><option value="All crates">All crates</option></select><input class="search-input" name="search" disabled autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"></div><a id="settings-menu" href="../settings.html"><img src="../wheel.svg" width="18" alt="Change settings"></a></div></form></nav><section id="main" class="content"><h1 class='fqn'><span class='out-of-band'><span id='render-detail'><a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs">[<span class='inner'>−</span>]</a></span><a class='srclink' href='../src/nom/branch.rs.html#281-360' title='goto source code'>[src]</a></span><span class='in-band'>Macro <a href='index.html'>nom</a>::<wbr><a class="macro" href=''>alt_complete</a></span></h1><div class="docblock type-decl hidden-by-usual-hider"><div class="example-wrap"><pre class="rust macro">
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<span class="macro">macro_rules</span><span class="macro">!</span> <span class="ident">alt_complete</span> {
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(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">i</span>:<span class="ident">expr</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">e</span>:<span class="ident">path</span> <span class="op">|</span> $(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">rest</span>:<span class="ident">tt</span>)<span class="kw-2">*</span>) <span class="op">=</span><span class="op">></span> { ... };
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(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">i</span>:<span class="ident">expr</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">subrule</span>:<span class="macro">ident</span><span class="macro">!</span>( $(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">args</span>:<span class="ident">tt</span>)<span class="kw-2">*</span>) <span class="op">|</span> $(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">rest</span>:<span class="ident">tt</span>)<span class="kw-2">*</span>) <span class="op">=</span><span class="op">></span> { ... };
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(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">i</span>:<span class="ident">expr</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">subrule</span>:<span class="macro">ident</span><span class="macro">!</span>( $(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">args</span>:<span class="ident">tt</span>)<span class="op">*</span> ) <span class="op">=</span><span class="op">></span> { <span class="macro-nonterminal">$</span><span class="macro-nonterminal">gen</span>:<span class="ident">expr</span> } <span class="op">|</span> $(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">rest</span>:<span class="ident">tt</span>)<span class="op">+</span>) <span class="op">=</span><span class="op">></span> { ... };
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(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">i</span>:<span class="ident">expr</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">e</span>:<span class="ident">path</span> <span class="op">=</span><span class="op">></span> { <span class="macro-nonterminal">$</span><span class="macro-nonterminal">gen</span>:<span class="ident">expr</span> } <span class="op">|</span> $(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">rest</span>:<span class="ident">tt</span>)<span class="kw-2">*</span>) <span class="op">=</span><span class="op">></span> { ... };
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(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">i</span>:<span class="ident">expr</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">e</span>:<span class="ident">path</span> <span class="op">=</span><span class="op">></span> { <span class="macro-nonterminal">$</span><span class="macro-nonterminal">gen</span>:<span class="ident">expr</span> }) <span class="op">=</span><span class="op">></span> { ... };
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(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">i</span>:<span class="ident">expr</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">subrule</span>:<span class="macro">ident</span><span class="macro">!</span>( $(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">args</span>:<span class="ident">tt</span>)<span class="op">*</span> ) <span class="op">=</span><span class="op">></span> { <span class="macro-nonterminal">$</span><span class="macro-nonterminal">gen</span>:<span class="ident">expr</span> }) <span class="op">=</span><span class="op">></span> { ... };
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(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">i</span>:<span class="ident">expr</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">e</span>:<span class="ident">path</span>) <span class="op">=</span><span class="op">></span> { ... };
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(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">i</span>:<span class="ident">expr</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">subrule</span>:<span class="macro">ident</span><span class="macro">!</span>( $(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">args</span>:<span class="ident">tt</span>)<span class="kw-2">*</span>)) <span class="op">=</span><span class="op">></span> { ... };
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}</pre></div>
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</div><div class='docblock'><p>Is equivalent to the <code>alt!</code> combinator, except that it will not return <code>Incomplete</code>
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when one of the constituting parsers returns <code>Incomplete</code>. Instead, it will try the
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next alternative in the chain.</p>
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<p>You should use this combinator only if you know you
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will not receive partial input for the rules you're trying to match (this
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is almost always the case for parsing programming languages).</p>
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<div class='information'><div class='tooltip ignore'>ⓘ<span class='tooltiptext'>This example is not tested</span></div></div><div class="example-wrap"><pre class="rust rust-example-rendered ignore">
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<span class="macro">alt_complete</span><span class="macro">!</span>(<span class="ident">I</span> <span class="op">-</span><span class="op">></span> <span class="ident">IResult</span><span class="op"><</span><span class="ident">I</span>,<span class="ident">O</span><span class="op">></span> <span class="op">|</span> <span class="ident">I</span> <span class="op">-</span><span class="op">></span> <span class="ident">IResult</span><span class="op"><</span><span class="ident">I</span>,<span class="ident">O</span><span class="op">></span> <span class="op">|</span> ... <span class="op">|</span> <span class="ident">I</span> <span class="op">-</span><span class="op">></span> <span class="ident">IResult</span><span class="op"><</span><span class="ident">I</span>,<span class="ident">O</span><span class="op">></span> ) <span class="op">=</span><span class="op">></span> <span class="ident">I</span> <span class="op">-</span><span class="op">></span> <span class="ident">IResult</span><span class="op"><</span><span class="ident">I</span>, <span class="ident">O</span><span class="op">></span></pre></div>
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<p>All the parsers must have the same return type.</p>
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<p>If one of the parsers return <code>Incomplete</code>, <code>alt_complete!</code> will try the next alternative.
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If there is no other parser left to try, an <code>Error</code> will be returned.</p>
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<div class='information'><div class='tooltip ignore'>ⓘ<span class='tooltiptext'>This example is not tested</span></div></div><div class="example-wrap"><pre class="rust rust-example-rendered ignore">
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<span class="macro">alt_complete</span><span class="macro">!</span>(<span class="ident">parser_1</span> <span class="op">|</span> <span class="ident">parser_2</span> <span class="op">|</span> ... <span class="op">|</span> <span class="ident">parser_n</span>)</pre></div>
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<p><strong>For more in depth examples, refer to the documentation of <code>alt!</code></strong></p>
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