<!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="Defines a high-level intermediate (HIR) representation for regular expressions."><title>regex_syntax::hir - 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="regex_syntax"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 mod"><!--[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_syntax/index.html">regex_syntax</a><spanclass="version">0.8.3</span></h2></div><h2class="location"><ahref="#">Module hir</a></h2><divclass="sidebar-elems"><section><ulclass="block"><li><ahref="#modules">Modules</a></li><li><ahref="#structs">Structs</a></li><li><ahref="#enums">Enums</a></li><li><ahref="#traits">Traits</a></li><li><ahref="#functions">Functions</a></li></ul></section><h2><ahref="../index.html">In crate regex_syntax</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="../../regex_syntax/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>Module <ahref="../index.html">regex_syntax</a>::<wbr><aclass="mod"href="#">hir</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/regex_syntax/hir/mod.rs.html#1-3877">source</a> · <buttonid="toggle-all-docs"title="collapse all docs">[<span>−</span>]</button></span></div><detailsclass="toggle top-doc"open><summaryclass="hideme"><span>Expand description</span></summary><divclass="docblock"><p>Defines a high-level intermediate (HIR) representation for regular expressions.</p>
<p>The HIR is represented by the <ahref="struct.Hir.html"title="struct regex_syntax::hir::Hir"><code>Hir</code></a> type, and it principally constructed via
<ahref="translate/index.html"title="mod regex_syntax::hir::translate">translation</a> from an <ahref="../ast/enum.Ast.html"title="enum regex_syntax::ast::Ast"><code>Ast</code></a>. Alternatively, users
may use the smart constructors defined on <code>Hir</code> to build their own by hand. The
smart constructors simultaneously simplify and “optimize” the HIR, and are also
the same routines used by translation.</p>
<p>Most regex engines only have an HIR like this, and usually construct it
directly from the concrete syntax. This crate however first parses the
concrete syntax into an <code>Ast</code>, and only then creates the HIR from the <code>Ast</code>,
as mentioned above. It’s done this way to facilitate better error reporting,
and to have a structured representation of a regex that faithfully represents
its concrete syntax. Namely, while an <code>Hir</code> value can be converted back to an
equivalent regex pattern string, it is unlikely to look like the original due
</div></details><h2id="modules"class="section-header">Modules<ahref="#modules"class="anchor">§</a></h2><ulclass="item-table"><li><divclass="item-name"><aclass="mod"href="literal/index.html"title="mod regex_syntax::hir::literal">literal</a></div><divclass="desc docblock-short">Provides literal extraction from <code>Hir</code> expressions.</div></li><li><divclass="item-name"><aclass="mod"href="print/index.html"title="mod regex_syntax::hir::print">print</a></div><divclass="desc docblock-short">This module provides a regular expression printer for <code>Hir</code>.</div></li><li><divclass="item-name"><aclass="mod"href="translate/index.html"title="mod regex_syntax::hir::translate">translate</a></div><divclass="desc docblock-short">Defines a translator that converts an <code>Ast</code> to an <code>Hir</code>.</div></li></ul><h2id="structs"class="section-header">Structs<ahref="#structs"class="anchor">§</a></h2><ulclass="item-table"><li><divclass="item-name"><aclass="struct"href="struct.Capture.html"title="struct regex_syntax::hir::Capture">Capture</a></div><divclass="desc docblock-short">The high-level intermediate representation for a capturing group.</div></li><li><divclass="item-name"><aclass="struct"href="struct.CaseFoldError.html"title="struct regex_syntax::hir::CaseFoldError">CaseFoldError</a></div><divclass="desc docblock-short">An error that occurs when Unicode-aware simple case folding fails.</div></li><li><divclass="item-name"><aclass="struct"href="struct.ClassBytes.html"title="struct regex_syntax::hir::ClassBytes">ClassBytes</a></div><divclass="desc docblock-short">A set of characters represented by arbitrary bytes.</div></li><li><divclass="item-name"><aclass="struct"href="struct.ClassBytesIter.html"title="struct regex_syntax::hir::ClassBytesIter">ClassBytesIter</a></div><divclass="desc docblock-short">An iterator over all ranges in a byte character class.</div></li><li><divclass="item-name"><aclass="struct"href="struct.ClassBytesRange.html"title="struct regex_syntax::hir::ClassBytesRange">ClassBytesRange</a></div><divclass="desc docblock-short">A single range of characters represented by arbitrary bytes.</div></li><li><divclass="item-name"><aclass="struct"href="struct.ClassUnicode.html"title="struct regex_syntax::hir::ClassUnicode">ClassUnicode</a></div><divclass="desc docblock-short">A set of characters represented by Unicode scalar values.</div></li><li><divclass="item-name"><aclass="struct"href="struct.ClassUnicodeIter.html"title="struct regex_syntax::hir::ClassUnicodeIter">ClassUnicodeIter</a></div><divclass="desc docblock-short">An iterator over all ranges in a Unicode character class.</div></li><li><divclass="item-name"><aclass="struct"href="struct.ClassUnicodeRange.html"title="struct regex_syntax::hir::ClassUnicodeRange">ClassUnicodeRange</a></div><divclass="desc docblock-short">A single range of characters represented by Unicode scalar values.</div></li><li><divclass="item-name"><aclass="struct"href="struct.Error.html"title="struct regex_syntax::hir::Error">Error</a></div><divclass="desc docblock-short">An error that can occur while translating an <code>Ast</code> to a <code>Hir</code>.</div></li><li><divclass="item-name"><aclass="struct"href="struct.Hir.html"title="struct regex_syntax::hir::Hir">Hir</a></div><divclass="desc docblock-short">A high-level intermediate representation (HIR) for a regular expression.</div></li><li><divclass="item-name"><aclass="struct"href="struct.Literal.html"title="struct regex_syntax::hir::Literal">Literal</a></div><divclass="desc docblock-short">The high-level intermediate representation of a literal.</div></li><li><divclass="item-name"><aclass="struct"href="struct.LookSet.html"title="struct regex_syntax::hir::LookSet">LookSet</a></div><divclass="desc docblock-short">A set of look-around assertions.</div></li><li><divclass="item-name"><aclass="struct"href="struct.LookSetIter.html"title="struct regex_syntax::hir::LookSetIter">LookSetIter</a></div><divclass="desc docblock-short">An iter
