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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="Recognize an input slice containing the first N input elements (I[..N])."><title>take in winnow::token - Rust</title><script>if(window.location.protocol!=="file:")document.head.insertAdjacentHTML("beforeend","SourceSerif4-Regular-46f98efaafac5295.ttf.woff2,FiraSans-Regular-018c141bf0843ffd.woff2,FiraSans-Medium-8f9a781e4970d388.woff2,SourceCodePro-Regular-562dcc5011b6de7d.ttf.woff2,SourceCodePro-Semibold-d899c5a5c4aeb14a.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-76eba96aa4d2e634.css"><link rel="stylesheet" href="../../static.files/rustdoc-dd39b87e5fcfba68.css"><meta name="rustdoc-vars" data-root-path="../../" data-static-root-path="../../static.files/" data-current-crate="winnow" data-themes="" data-resource-suffix="" data-rustdoc-version="1.80.0 (051478957 2024-07-21)" data-channel="1.80.0" data-search-js="search-d52510db62a78183.js" data-settings-js="settings-4313503d2e1961c2.js" ><script src="../../static.files/storage-118b08c4c78b968e.js"></script><script defer src="sidebar-items.js"></script><script defer src="../../static.files/main-20a3ad099b048cf2.js"></script><noscript><link rel="stylesheet" href="../../static.files/noscript-df360f571f6edeae.css"></noscript><link rel="alternate icon" type="image/png" href="../../static.files/favicon-32x32-422f7d1d52889060.png"><link rel="icon" type="image/svg+xml" href="../../static.files/favicon-2c020d218678b618.svg"></head><body class="rustdoc fn"><!--[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="../../winnow/index.html">winnow</a><span class="version">0.6.18</span></h2></div><div class="sidebar-elems"><h2><a href="index.html">In winnow::token</a></h2></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"><h1>Function <a href="../index.html">winnow</a>::<wbr><a href="index.html">token</a>::<wbr><a class="fn" href="#">take</a><button id="copy-path" title="Copy item path to clipboard">Copy item path</button></h1><span class="out-of-band"><a class="src" href="../../src/winnow/token/mod.rs.html#851-867">source</a> · <button id="toggle-all-docs" title="collapse all docs">[<span>&#x2212;</span>]</button></span></div><pre class="rust item-decl"><code>pub fn take&lt;UsizeLike, Input, Error&gt;(
token_count: UsizeLike,
) -&gt; impl <a class="trait" href="../trait.Parser.html" title="trait winnow::Parser">Parser</a>&lt;Input, &lt;Input as <a class="trait" href="../stream/trait.Stream.html" title="trait winnow::stream::Stream">Stream</a>&gt;::<a class="associatedtype" href="../stream/trait.Stream.html#associatedtype.Slice" title="type winnow::stream::Stream::Slice">Slice</a>, Error&gt;<div class="where">where
Input: <a class="trait" href="../stream/trait.StreamIsPartial.html" title="trait winnow::stream::StreamIsPartial">StreamIsPartial</a> + <a class="trait" href="../stream/trait.Stream.html" title="trait winnow::stream::Stream">Stream</a>,
UsizeLike: <a class="trait" href="../stream/trait.ToUsize.html" title="trait winnow::stream::ToUsize">ToUsize</a>,
Error: <a class="trait" href="../error/trait.ParserError.html" title="trait winnow::error::ParserError">ParserError</a>&lt;Input&gt;,</div></code></pre><details class="toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Recognize an input slice containing the first N input elements (I[..N]).</p>
<p><em>Complete version</em>: It will return <code>Err(ErrMode::Backtrack(InputError::new(_, ErrorKind::Slice)))</code> if the input is shorter than the argument.</p>
<p><em>[Partial version][crate::_topic::partial]</em>: if the input has less than N elements, <code>take</code> will
return a <code>ErrMode::Incomplete(Needed::new(M))</code> where M is the number of
additional bytes the parser would need to succeed.
It is well defined for <code>&amp;[u8]</code> as the number of elements is the byte size,
but for types like <code>&amp;str</code>, we cannot know how many bytes correspond for
the next few chars, so the result will be <code>ErrMode::Incomplete(Needed::Unknown)</code></p>
<h2 id="effective-signature"><a class="doc-anchor" href="#effective-signature">§</a>Effective Signature</h2>
<p>Assuming you are parsing a <code>&amp;str</code> <a href="../stream/trait.Stream.html" title="trait winnow::stream::Stream">Stream</a> with <code>0..</code> or <code>1..</code> ranges:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">pub fn </span>take&lt;<span class="lifetime">'i</span>&gt;(token_count: usize) -&gt; <span class="kw">impl </span>Parser&lt;<span class="kw-2">&amp;</span><span class="lifetime">'i </span>str, <span class="kw-2">&amp;</span><span class="lifetime">'i </span>str, ContextError&gt;</code></pre></div>
<h2 id="example"><a class="doc-anchor" href="#example">§</a>Example</h2>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>winnow::token::take;
<span class="kw">fn </span>take6(s: <span class="kw-2">&amp;</span>str) -&gt; IResult&lt;<span class="kw-2">&amp;</span>str, <span class="kw-2">&amp;</span>str&gt; {
take(<span class="number">6usize</span>).parse_peek(s)
}
<span class="macro">assert_eq!</span>(take6(<span class="string">"1234567"</span>), <span class="prelude-val">Ok</span>((<span class="string">"7"</span>, <span class="string">"123456"</span>)));
<span class="macro">assert_eq!</span>(take6(<span class="string">"things"</span>), <span class="prelude-val">Ok</span>((<span class="string">""</span>, <span class="string">"things"</span>)));
<span class="macro">assert_eq!</span>(take6(<span class="string">"short"</span>), <span class="prelude-val">Err</span>(ErrMode::Backtrack(InputError::new(<span class="string">"short"</span>, ErrorKind::Slice))));
<span class="macro">assert_eq!</span>(take6(<span class="string">""</span>), <span class="prelude-val">Err</span>(ErrMode::Backtrack(InputError::new(<span class="string">""</span>, ErrorKind::Slice))));</code></pre></div>
<p>The units that are taken will depend on the input type. For example, for a
<code>&amp;str</code> it will take a number of <code>char</code>s, whereas for a <code>&amp;[u8]</code> it will
take that many <code>u8</code>s:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>winnow::error::InputError;
<span class="kw">use </span>winnow::token::take;
<span class="macro">assert_eq!</span>(take::&lt;<span class="kw">_</span>, <span class="kw">_</span>, InputError&lt;<span class="kw">_</span>&gt;&gt;(<span class="number">1usize</span>).parse_peek(<span class="string">"💙"</span>), <span class="prelude-val">Ok</span>((<span class="string">""</span>, <span class="string">"💙"</span>)));
<span class="macro">assert_eq!</span>(take::&lt;<span class="kw">_</span>, <span class="kw">_</span>, InputError&lt;<span class="kw">_</span>&gt;&gt;(<span class="number">1usize</span>).parse_peek(<span class="string">"💙"</span>.as_bytes()), <span class="prelude-val">Ok</span>((<span class="string">b"\x9F\x92\x99"</span>.as_ref(), <span class="string">b"\xF0"</span>.as_ref())));</code></pre></div>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>winnow::token::take;
<span class="kw">fn </span>take6(s: Partial&lt;<span class="kw-2">&amp;</span>str&gt;) -&gt; IResult&lt;Partial&lt;<span class="kw-2">&amp;</span>str&gt;, <span class="kw-2">&amp;</span>str&gt; {
take(<span class="number">6usize</span>).parse_peek(s)
}
<span class="macro">assert_eq!</span>(take6(Partial::new(<span class="string">"1234567"</span>)), <span class="prelude-val">Ok</span>((Partial::new(<span class="string">"7"</span>), <span class="string">"123456"</span>)));
<span class="macro">assert_eq!</span>(take6(Partial::new(<span class="string">"things"</span>)), <span class="prelude-val">Ok</span>((Partial::new(<span class="string">""</span>), <span class="string">"things"</span>)));
<span class="comment">// `Unknown` as we don't know the number of bytes that `count` corresponds to
</span><span class="macro">assert_eq!</span>(take6(Partial::new(<span class="string">"short"</span>)), <span class="prelude-val">Err</span>(ErrMode::Incomplete(Needed::Unknown)));</code></pre></div>
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