edlang/clap/macro.arg.html
2024-03-11 07:31:05 +00:00

64 lines
8.6 KiB
HTML
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

<!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="Create an `Arg` from a usage string."><title>arg in clap - Rust</title><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"><link rel="stylesheet" href="../static.files/normalize-76eba96aa4d2e634.css"><link rel="stylesheet" href="../static.files/rustdoc-ac92e1bbe349e143.css"><meta name="rustdoc-vars" data-root-path="../" data-static-root-path="../static.files/" data-current-crate="clap" data-themes="" data-resource-suffix="" data-rustdoc-version="1.76.0 (07dca489a 2024-02-04)" data-channel="1.76.0" data-search-js="search-2b6ce74ff89ae146.js" data-settings-js="settings-4313503d2e1961c2.js" ><script src="../static.files/storage-f2adc0d6ca4d09fb.js"></script><script defer src="sidebar-items.js"></script><script defer src="../static.files/main-305769736d49e732.js"></script><noscript><link rel="stylesheet" href="../static.files/noscript-feafe1bb7466e4bd.css"></noscript><link rel="alternate icon" type="image/png" href="../static.files/favicon-16x16-8b506e7a72182f1c.png"><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 macro"><!--[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">&#9776;</button><a class="logo-container" href="../clap/index.html"><img src="https://raw.githubusercontent.com/clap-rs/clap/master/assets/clap.png" alt=""></a></nav><nav class="sidebar"><div class="sidebar-crate"><a class="logo-container" href="../clap/index.html"><img src="https://raw.githubusercontent.com/clap-rs/clap/master/assets/clap.png" alt="logo"></a><h2><a href="../clap/index.html">clap</a><span class="version">4.5.2</span></h2></div><div class="sidebar-elems"></div></nav><div class="sidebar-resizer"></div>
<main><div class="width-limiter"><nav class="sub"><form class="search-form"><span></span><div id="sidebar-button" tabindex="-1"><a href="../clap/all.html" title="show sidebar"></a></div><input class="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"><div id="help-button" tabindex="-1"><a href="../help.html" title="help">?</a></div><div id="settings-menu" tabindex="-1"><a href="../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../static.files/wheel-7b819b6101059cd0.svg"></a></div></form></nav><section id="main-content" class="content"><div class="main-heading"><h1>Macro <a href="index.html">clap</a>::<wbr><a class="macro" href="#">arg</a><button id="copy-path" title="Copy item path to clipboard"><img src="../static.files/clipboard-7571035ce49a181d.svg" width="19" height="18" alt="Copy item path"></button></h1><span class="out-of-band"><a class="src" href="../src/clap_builder/macros.rs.html#516">source</a> · <button id="toggle-all-docs" title="collapse all docs">[<span>&#x2212;</span>]</button></span></div><pre class="rust item-decl"><span class="macro">macro_rules! </span>arg {
( <span class="macro-nonterminal">$name</span>:ident: $(<span class="macro-nonterminal">$tail</span>:tt)+ ) =&gt; { ... };
( $(<span class="macro-nonterminal">$tail</span>:tt)+ ) =&gt; { ... };
}</pre><details class="toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Create an <a href="struct.Arg.html" title="struct clap::Arg"><code>Arg</code></a> from a usage string.</p>
<p>Allows creation of basic settings for the <a href="struct.Arg.html" title="struct clap::Arg"><code>Arg</code></a>.</p>
<p><strong>NOTE</strong>: Not all settings may be set using the usage string method. Some properties are
only available via the builder pattern.</p>
<h2 id="syntax"><a href="#syntax">Syntax</a></h2>
<p>Usage strings typically following the form:</p>
<div class="example-wrap"><pre class="language-notrust"><code>[explicit name] [short] [long] [value names] [...] [help string]
</code></pre></div><h4 id="explicit-name"><a href="#explicit-name">Explicit Name</a></h4>
<p>The name may be either a bare-word or a string, followed by a <code>:</code>, like <code>name:</code> or
<code>&quot;name&quot;:</code>.</p>
<p><em>Note:</em> This is an optional field, if its omitted the argument will use one of the additional
fields as the name using the following priority order:</p>
<ol>
<li>Explicit Name</li>
<li>Long</li>
<li>Value Name</li>
</ol>
<p>See <a href="struct.Arg.html#method.id" title="method clap::Arg::id"><code>Arg::id</code></a>.</p>
<h4 id="short"><a href="#short">Short</a></h4>
<p>A short flag is a <code>-</code> followed by either a bare-character or quoted character, like <code>-f</code> or
<code>-'f'</code>.</p>
<p>See <a href="struct.Arg.html#method.short" title="method clap::Arg::short"><code>Arg::short</code></a>.</p>
<h4 id="long"><a href="#long">Long</a></h4>
<p>A long flag is a <code>--</code> followed by either a bare-word or a string, like <code>--foo</code> or
<code>--&quot;foo&quot;</code>.</p>
<p><strong>NOTE:</strong> Dashes in the long name (e.g. <code>--foo-bar</code>) is not supported and quoting is required
(e.g. <code>--&quot;foo-bar&quot;</code>).</p>
<p>See <a href="struct.Arg.html#method.long" title="method clap::Arg::long"><code>Arg::long</code></a>.</p>
<h4 id="values-value-notation"><a href="#values-value-notation">Values (Value Notation)</a></h4>
<p>This is set by placing bare-word between:</p>
<ul>
<li><code>[]</code> like <code>[FOO]</code>
<ul>
<li>Positional argument: optional</li>
<li>Named argument: optional value</li>
</ul>
</li>
<li><code>&lt;&gt;</code> like <code>&lt;FOO&gt;</code>: required</li>
</ul>
<p>See <a href="struct.Arg.html#method.value_name" title="method clap::Arg::value_name"><code>Arg::value_name</code></a>.</p>
<h4 id=""><a href="#"><code>...</code></a></h4>
<p><code>...</code> (three consecutive dots/periods) specifies that this argument may occur multiple
times (not to be confused with multiple values per occurrence).</p>
<p>See <a href="enum.ArgAction.html#variant.Count" title="variant clap::ArgAction::Count"><code>ArgAction::Count</code></a> and <a href="enum.ArgAction.html#variant.Append" title="variant clap::ArgAction::Append"><code>ArgAction::Append</code></a>.</p>
<h4 id="help-string"><a href="#help-string">Help String</a></h4>
<p>The help string is denoted between a pair of double quotes <code>&quot;&quot;</code> and may contain any
characters.</p>
<h2 id="examples"><a href="#examples">Examples</a></h2>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">let </span>cmd = Command::new(<span class="string">"prog"</span>)
.args(<span class="kw-2">&amp;</span>[
<span class="macro">arg!</span>(--config &lt;FILE&gt; <span class="string">"a required file for the configuration and no short"</span>),
<span class="macro">arg!</span>(-d --debug ... <span class="string">"turns on debugging information and allows multiples"</span>),
<span class="macro">arg!</span>([input] <span class="string">"an optional input file to use"</span>)
]);
<span class="kw">let </span>m = cmd.try_get_matches_from([<span class="string">"prog"</span>, <span class="string">"--config"</span>, <span class="string">"file.toml"</span>]).unwrap();
<span class="macro">assert_eq!</span>(m.get_one::&lt;String&gt;(<span class="string">"config"</span>).unwrap(), <span class="string">"file.toml"</span>);
<span class="macro">assert_eq!</span>(<span class="kw-2">*</span>m.get_one::&lt;u8&gt;(<span class="string">"debug"</span>).unwrap(), <span class="number">0</span>);
<span class="macro">assert_eq!</span>(m.get_one::&lt;String&gt;(<span class="string">"input"</span>), <span class="prelude-val">None</span>);</code></pre></div>
</div></details></section></div></main></body></html>