<!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="Parse command-line arguments into `Self`."><title>Parser in clap - Rust</title><script>if(window.location.protocol!=="file:")document.write(`<link rel="preload" as="font" type="font/woff2" crossorigin href="../static.files/SourceSerif4-Regular-46f98efaafac5295.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../static.files/FiraSans-Regular-018c141bf0843ffd.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../static.files/FiraSans-Medium-8f9a781e4970d388.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../static.files/SourceCodePro-Regular-562dcc5011b6de7d.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../static.files/SourceCodePro-Semibold-d899c5a5c4aeb14a.ttf.woff2">`)</script><linkrel="stylesheet"href="../static.files/normalize-76eba96aa4d2e634.css"><linkrel="stylesheet"href="../static.files/rustdoc-e935ef01ae1c1829.css"><metaname="rustdoc-vars"data-root-path="../"data-static-root-path="../static.files/"data-current-crate="clap"data-themes=""data-resource-suffix=""data-rustdoc-version="1.78.0 (9b00956e5 2024-04-29)"data-channel="1.78.0"data-search-js="search-42d8da7a6b9792c2.js"data-settings-js="settings-4313503d2e1961c2.js"><scriptsrc="../static.files/storage-4c98445ec4002617.js"></script><scriptdefersrc="sidebar-items.js"></script><scriptdefersrc="../static.files/main-12cf3b4f4f9dc36d.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 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><aclass="logo-container"href="../clap/index.html"><imgsrc="https://raw.githubusercontent.com/clap-rs/clap/master/assets/clap.png"alt=""></a></nav><navclass="sidebar"><divclass="sidebar-crate"><aclass="logo-container"href="../clap/index.html"><imgsrc="https://raw.githubusercontent.com/clap-rs/clap/master/assets/clap.png"alt="logo"></a><h2><ahref="../clap/index.html">clap</a><spanclass="version">4.5.4</span></h2></div><h2class="location"><ahref="#">Parser</a></h2><divclass="sidebar-elems"><section><h3><ahref="#provided-methods">Provided Methods</a></h3><ulclass="block"><li><ahref="#method.parse">parse</a></li><li><ahref="#method.parse_from">parse_from</a></li><li><ahref="#method.try_parse">try_parse</a></li><li><ahref="#method.try_parse_from">try_parse_from</a></li><li><ahref="#method.try_update_from">try_update_from</a></li><li><ahref="#method.update_from">update_from</a></li></ul><h3><ahref="#foreign-impls">Implementations on Foreign Types</a></h3><ulclass="block"><li><ahref="#impl-Parser-for-Box%3CT%3E">Box<T></a></li></ul><h3><ahref="#object-safety">Object Safety</a></h3><h3><ahref="#implementors">Implementors</a></h3></section><h2><ahref="index.html">In crate clap</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="../clap/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>Trait <ahref="index.html">clap</a>::<wbr><aclass="trait"href="#">Parser</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/clap_builder/derive.rs.html#24">source</a> · <buttonid="toggle-all-docs"title="collapse all docs">[<span>−</span>]</button></span></div><preclass="rust item-decl"><code>pub trait Parser: <aclass="trait"href="https://doc.rust-lang.org/1.78.0/core/marker/trait.Sized.html"title="trait core::marker::Sized">Sized</a> + <aclass="trait"href="trait.FromArgMatches.html"title="trait clap::FromArgMatches">FromArgMatches</a> + <aclass="trait"href="trait.CommandFactory.html"title="trait clap::CommandFactory">CommandFactory</a> {
}</code></pre><detailsclass="toggle top-doc"open><summaryclass="hideme"><span>Expand description</span></summary><divclass="docblock"><p>Parse command-line arguments into <code>Self</code>.</p>
<p>The primary one-stop-shop trait used to create an instance of a <code>clap</code>
<ahref="struct.Command.html"title="struct clap::Command"><code>Command</code></a>, conduct the parsing, and turn the resulting <ahref="struct.ArgMatches.html"title="struct clap::ArgMatches"><code>ArgMatches</code></a> back
into concrete instance of the user struct.</p>
<p>This trait is primarily a convenience on top of <ahref="trait.FromArgMatches.html"title="trait clap::FromArgMatches"><code>FromArgMatches</code></a> +
<ahref="trait.CommandFactory.html"title="trait clap::CommandFactory"><code>CommandFactory</code></a> which uses those two underlying traits to build the two
fundamental functions <code>parse</code> which uses the <code>std::env::args_os</code> iterator,
and <code>parse_from</code> which allows the consumer to supply the iterator (along
with fallible options for each).</p>
<p>See also <ahref="trait.Subcommand.html"title="trait clap::Subcommand"><code>Subcommand</code></a> and <ahref="trait.Args.html"title="trait clap::Args"><code>Args</code></a>.</p>
<p><strong>NOTE:</strong> Deriving requires the <code>derive</code> feature flag</p>
</div></details><h2id="provided-methods"class="section-header">Provided Methods<ahref="#provided-methods"class="anchor">§</a></h2><divclass="methods"><detailsclass="toggle method-toggle"open><summary><sectionid="method.parse"class="method"><aclass="src rightside"href="../src/clap_builder/derive.rs.html#26">source</a><h4class="code-header">fn <ahref="#method.parse"class="fn">parse</a>() -> Self</h4></section></summary><divclass="docblock"><p>Parse from <code>std::env::args_os()</code>, <ahref="error/struct.Error.html#method.exit"title="method clap::error::Error::exit">exit</a> on error.</p>
T: <aclass="trait"href="https://doc.rust-lang.org/1.78.0/core/convert/trait.Into.html"title="trait core::convert::Into">Into</a><<aclass="struct"href="https://doc.rust-lang.org/1.78.0/std/ffi/os_str/struct.OsString.html"title="struct std::ffi::os_str::OsString">OsString</a>> + <aclass="trait"href="https://doc.rust-lang.org/1.78.0/core/clone/trait.Clone.html"title="trait core::clone::Clone">Clone</a>,</div></h4></section></summary><divclass="docblock"><p>Update from iterator, return Err on error.</p>
</div></details></div><h2id="object-safety"class="section-header">Object Safety<ahref="#object-safety"class="anchor">§</a></h2><divclass="object-safety-info">This trait is <b>not</b><ahref="https://doc.rust-lang.org/1.78.0/reference/items/traits.html#object-safety">object safe</a>.</div><h2id="foreign-impls"class="section-header">Implementations on Foreign Types<ahref="#foreign-impls"class="anchor">§</a></h2><detailsclass="toggle implementors-toggle"><summary><sectionid="impl-Parser-for-Box%3CT%3E"class="impl"><aclass="src rightside"href="../src/clap_builder/derive.rs.html#287">source</a><ahref="#impl-Parser-for-Box%3CT%3E"class="anchor">§</a><h3class="code-header">impl<T><aclass="trait"href="trait.Parser.html"title="trait clap::Parser">Parser</a> for <aclass="struct"href="https://doc.rust-lang.org/1.78.0/alloc/boxed/struct.Box.html"title="struct alloc::boxed::Box">Box</a><T><divclass="where">where
