<!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="A trait for types that can be used to replace matches in a haystack."><title>Replacer in regex::bytes - 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><linkrel="stylesheet"href="../../static.files/normalize-76eba96aa4d2e634.css"><linkrel="stylesheet"href="../../static.files/rustdoc-dd39b87e5fcfba68.css"><metaname="rustdoc-vars"data-root-path="../../"data-static-root-path="../../static.files/"data-current-crate="regex"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"><scriptsrc="../../static.files/storage-118b08c4c78b968e.js"></script><scriptdefersrc="sidebar-items.js"></script><scriptdefersrc="../../static.files/main-20a3ad099b048cf2.js"></script><noscript><linkrel="stylesheet"href="../../static.files/noscript-df360f571f6edeae.css"></noscript><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 trait"><!--[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="../../regex/index.html">regex</a><spanclass="version">1.10.5</span></h2></div><h2class="location"><ahref="#">Replacer</a></h2><divclass="sidebar-elems"><section><h3><ahref="#required-methods">Required Methods</a></h3><ulclass="block"><li><ahref="#tymethod.replace_append">replace_append</a></li></ul><h3><ahref="#provided-methods">Provided Methods</a></h3><ulclass="block"><li><ahref="#method.by_ref">by_ref</a></li><li><ahref="#method.no_expansion">no_expansion</a></li></ul><h3><ahref="#foreign-impls">Implementations on Foreign Types</a></h3><ulclass="block"><li><ahref="#impl-Replacer-for-%26Cow%3C'a,+%5Bu8%5D%3E">&'a Cow<'a, [u8]></a></li><li><ahref="#impl-Replacer-for-%26Vec%3Cu8%3E">&'a Vec<u8></a></li><li><ahref="#impl-Replacer-for-%26%5Bu8;+N%5D">&'a [u8; N]</a></li><li><ahref="#impl-Replacer-for-%26%5Bu8%5D">&'a [u8]</a></li><li><ahref="#impl-Replacer-for-Cow%3C'a,+%5Bu8%5D%3E">Cow<'a, [u8]></a></li><li><ahref="#impl-Replacer-for-Vec%3Cu8%3E">Vec<u8></a></li><li><ahref="#impl-Replacer-for-%5Bu8;+N%5D">[u8; N]</a></li></ul><h3><ahref="#object-safety">Object Safety</a></h3><h3><ahref="#implementors">Implementors</a></h3></section><h2><ahref="index.html">In regex::bytes</a></h2></div></nav><divclass="sidebar-resizer"></div><main><divclass="width-limiter"><rustdoc-search></rustdoc-search><sectionid="main-content"class="content"><divclass="main-heading"><h1>Trait <ahref="../index.html">regex</a>::<wbr><ahref="index.html">bytes</a>::<wbr><aclass="trait"href="#">Replacer</a><buttonid="copy-path"title="Copy item path to clipboard">Copy item path</button></h1><spanclass="out-of-band"><aclass="src"href="../../src/regex/regex/bytes.rs.html#2423-2470">source</a> · <buttonid="toggle-all-docs"title="collapse all docs">[<span>−</span>]</button></span></div><preclass="rust item-decl"><code>pub trait Replacer {
}</code></pre><detailsclass="toggle top-doc"open><summaryclass="hideme"><span>Expand description</span></summary><divclass="docblock"><p>A trait for types that can be used to replace matches in a haystack.</p>
<p>In general, users of this crate shouldn’t need to implement this trait,
since implementations are already provided for <code>&[u8]</code> along with other
variants of byte string types, as well as <code>FnMut(&Captures) -> Vec<u8></code> (or
any <code>FnMut(&Captures) -> T</code> where <code>T: AsRef<[u8]></code>). Those cover most use
cases, but callers can implement this trait directly if necessary.</p>
</div></details><h2id="required-methods"class="section-header">Required Methods<ahref="#required-methods"class="anchor">§</a></h2><divclass="methods"><detailsclass="toggle method-toggle"open><summary><sectionid="tymethod.replace_append"class="method"><aclass="src rightside"href="../../src/regex/regex/bytes.rs.html#2431">source</a><h4class="code-header">fn <ahref="#tymethod.replace_append"class="fn">replace_append</a>(&mut self, caps: &<aclass="struct"href="struct.Captures.html"title="struct regex::bytes::Captures">Captures</a><'_>, dst: &mut <aclass="struct"href="https://doc.rust-lang.org/1.80.0/alloc/vec/struct.Vec.html"title="struct alloc::vec::Vec">Vec</a><<aclass="primitive"href="https://doc.rust-lang.org/1.80.0/std/primitive.u8.html">u8</a>>)</h4></section></summary><divclass="docblock"><p>Appends possibly empty data to <code>dst</code> to replace the current match.</p>
<p>When doing replacements, if access to <ahref="struct.Captures.html"title="struct regex::bytes::Captures"><code>Captures</code></a> is not needed (e.g.,
the replacement byte string does not need <code>$</code> expansion), then it can
be beneficial to avoid finding sub-captures.</p>
<p>In general, this is called once for every call to a replacement routine
such as <ahref="struct.Regex.html#method.replace_all"title="method regex::bytes::Regex::replace_all"><code>Regex::replace_all</code></a>.</p>
</div></details><detailsclass="toggle method-toggle"open><summary><sectionid="method.by_ref"class="method"><aclass="src rightside"href="../../src/regex/regex/bytes.rs.html#2467-2469">source</a><h4class="code-header">fn <ahref="#method.by_ref"class="fn">by_ref</a><'r>(&'r mut self) -><aclass="struct"href="struct.ReplacerRef.html"title="struct regex::bytes::ReplacerRef">ReplacerRef</a><'r, Self></h4></section></summary><divclass="docblock"><p>Returns a type that implements <code>Replacer</code>, but that borrows and wraps
