<!DOCTYPE html><htmllang="en"><head><metacharset="utf-8"><metaname="viewport"content="width=device-width, initial-scale=1.0"><metaname="generator"content="rustdoc"><metaname="description"content="Recognize the longest (m <= len <= n) input slice that matches a set of tokens"><title>take_while in winnow::token - Rust</title><linkrel="preload"as="font"type="font/woff2"crossoriginhref="../../static.files/SourceSerif4-Regular-46f98efaafac5295.ttf.woff2"><linkrel="preload"as="font"type="font/woff2"crossoriginhref="../../static.files/FiraSans-Regular-018c141bf0843ffd.woff2"><linkrel="preload"as="font"type="font/woff2"crossoriginhref="../../static.files/FiraSans-Medium-8f9a781e4970d388.woff2"><linkrel="preload"as="font"type="font/woff2"crossoriginhref="../../static.files/SourceCodePro-Regular-562dcc5011b6de7d.ttf.woff2"><linkrel="preload"as="font"type="font/woff2"crossoriginhref="../../static.files/SourceCodePro-Semibold-d899c5a5c4aeb14a.ttf.woff2"><linkrel="stylesheet"href="../../static.files/normalize-76eba96aa4d2e634.css"><linkrel="stylesheet"href="../../static.files/rustdoc-5bc39a1768837dd0.css"><metaname="rustdoc-vars"data-root-path="../../"data-static-root-path="../../static.files/"data-current-crate="winnow"data-themes=""data-resource-suffix=""data-rustdoc-version="1.77.0 (aedd173a2 2024-03-17)"data-channel="1.77.0"data-search-js="search-dd67cee4cfa65049.js"data-settings-js="settings-4313503d2e1961c2.js"><scriptsrc="../../static.files/storage-4c98445ec4002617.js"></script><scriptdefersrc="sidebar-items.js"></script><scriptdefersrc="../../static.files/main-48f368f3872407c8.js"></script><noscript><linkrel="stylesheet"href="../../static.files/noscript-04d5337699b92874.css"></noscript><linkrel="alternate icon"type="image/png"href="../../static.files/favicon-16x16-8b506e7a72182f1c.png"><linkrel="alternate icon"type="image/png"href="../../static.files/favicon-32x32-422f7d1d52889060.png"><linkrel="icon"type="image/svg+xml"href="../../static.files/favicon-2c020d218678b618.svg"></head><bodyclass="rustdoc fn"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><navclass="mobile-topbar"><buttonclass="sidebar-menu-toggle"title="show sidebar"></button></nav><navclass="sidebar"><divclass="sidebar-crate"><h2><ahref="../../winnow/index.html">winnow</a><spanclass="version">0.6.5</span></h2></div><divclass="sidebar-elems"><h2><ahref="index.html">In winnow::token</a></h2></div></nav><divclass="sidebar-resizer"></div>
<main><divclass="width-limiter"><navclass="sub"><formclass="search-form"><span></span><divid="sidebar-button"tabindex="-1"><ahref="../../winnow/all.html"title="show sidebar"></a></div><inputclass="search-input"name="search"aria-label="Run search in the documentation"autocomplete="off"spellcheck="false"placeholder="Click or press ‘S’ to search, ‘?’ for more options…"type="search"><divid="help-button"tabindex="-1"><ahref="../../help.html"title="help">?</a></div><divid="settings-menu"tabindex="-1"><ahref="../../settings.html"title="settings"><imgwidth="22"height="22"alt="Change settings"src="../../static.files/wheel-7b819b6101059cd0.svg"></a></div></form></nav><sectionid="main-content"class="content"><divclass="main-heading"><h1>Function <ahref="../index.html">winnow</a>::<wbr><ahref="index.html">token</a>::<wbr><aclass="fn"href="#">take_while</a><buttonid="copy-path"title="Copy item path to clipboard"><imgsrc="../../static.files/clipboard-7571035ce49a181d.svg"width="19"height="18"alt="Copy item path"></button></h1><spanclass="out-of-band"><aclass="src"href="../../src/winnow/token/mod.rs.html#478-517">source</a> · <buttonid="toggle-all-docs"title="collapse all docs">[<span>−</span>]</button></span></div><preclass="rust item-decl"><code>pub fn take_while<Set, Input, Error>(
Set: <aclass="trait"href="../stream/trait.ContainsToken.html"title="trait winnow::stream::ContainsToken">ContainsToken</a><<Input as <aclass="trait"href="../stream/trait.Stream.html"title="trait winnow::stream::Stream">Stream</a>>::<aclass="associatedtype"href="../stream/trait.Stream.html#associatedtype.Token"title="type winnow::stream::Stream::Token">Token</a>>,
Error: <aclass="trait"href="../error/trait.ParserError.html"title="trait winnow::error::ParserError">ParserError</a><Input>,</div></code></pre><detailsclass="toggle top-doc"open><summaryclass="hideme"><span>Expand description</span></summary><divclass="docblock"><p>Recognize the longest (m <= len <= n) input slice that matches a <ahref="../stream/trait.ContainsToken.html"title="trait winnow::stream::ContainsToken">set of tokens</a></p>
<p>It will return an <code>ErrMode::Backtrack(InputError::new(_, ErrorKind::Slice))</code> if the set of tokens wasn’t met or is out
of range (m <= len <= n).</p>
<p><em>[Partial version][crate::_topic::partial]</em> will return a <code>ErrMode::Incomplete(Needed::new(1))</code> if a member of the set of tokens reaches the end of the input or is too short.</p>
<p>To recognize a series of tokens, use <ahref="../combinator/fn.repeat.html"title="fn winnow::combinator::repeat"><code>repeat</code></a> to <ahref="../stream/trait.Accumulate.html"title="trait winnow::stream::Accumulate"><code>Accumulate</code></a> into a <code>()</code> and then <ahref="../trait.Parser.html#method.recognize"title="method winnow::Parser::recognize"><code>Parser::recognize</code></a>.</p>
<p>Assuming you are parsing a <code>&str</code><ahref="../stream/trait.Stream.html"title="trait winnow::stream::Stream">Stream</a> with <code>0..</code> or <code>1..</code><ahref="../stream/struct.Range.html"title="struct winnow::stream::Range">ranges</a>:</p>
<spanclass="macro">assert_eq!</span>(hex(<spanclass="string">"123 and voila"</span>), <spanclass="prelude-val">Ok</span>((<spanclass="string">" and voila"</span>, <spanclass="string">"123"</span>)));
<spanclass="macro">assert_eq!</span>(hex(<spanclass="string">"DEADBEEF and others"</span>), <spanclass="prelude-val">Ok</span>((<spanclass="string">" and others"</span>, <spanclass="string">"DEADBEEF"</span>)));
<spanclass="macro">assert_eq!</span>(hex(Partial::new(<spanclass="string">"123 and voila"</span>)), <spanclass="prelude-val">Ok</span>((Partial::new(<spanclass="string">" and voila"</span>), <spanclass="string">"123"</span>)));
<spanclass="macro">assert_eq!</span>(hex(Partial::new(<spanclass="string">"DEADBEEF and others"</span>)), <spanclass="prelude-val">Ok</span>((Partial::new(<spanclass="string">" and others"</span>), <spanclass="string">"DEADBEEF"</span>)));
