| <!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="Convenience macro to generate more complete enums with variants to be used as a type when parsing arguments. This enum also provides a `variants()` function which can be used to retrieve a `Vec<&'static str>` of the variant names, as well as implementing `FromStr` and `Display` automatically."><meta name="keywords" content="rust, rustlang, rust-lang, arg_enum"><title>arg_enum in clap - Rust</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../SourceSerif4-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../FiraSans-Regular.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../FiraSans-Medium.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../SourceCodePro-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../SourceSerif4-Bold.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../SourceCodePro-Semibold.ttf.woff2"><link rel="stylesheet" href="../normalize.css"><link rel="stylesheet" href="../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" href="../ayu.css" disabled><link rel="stylesheet" href="../dark.css" disabled><link rel="stylesheet" href="../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../storage.js"></script><script defer src="sidebar-items.js"></script><script defer src="../main.js"></script><noscript><link rel="stylesheet" href="../noscript.css"></noscript><link rel="alternate icon" type="image/png" href="../favicon-16x16.png"><link rel="alternate icon" type="image/png" href="../favicon-32x32.png"><link rel="icon" type="image/svg+xml" href="../favicon.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">☰</button><a class="sidebar-logo" href="../clap/index.html"><div class="logo-container"><img class="rust-logo" src="../rust-logo.svg" alt="logo"></div></a><h2></h2></nav><nav class="sidebar"><a class="sidebar-logo" href="../clap/index.html"><div class="logo-container"><img class="rust-logo" src="../rust-logo.svg" alt="logo"></div></a><div class="sidebar-elems"><h2><a href="index.html">In clap</a></h2></div></nav><main><div class="width-limiter"><nav class="sub"><form class="search-form"><div class="search-container"><span></span><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><div id="help-button" title="help" tabindex="-1"><a href="../help.html">?</a></div><div id="settings-menu" tabindex="-1"><a href="../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../wheel.svg"></a></div></div></form></nav><section id="main-content" class="content"><div class="main-heading"><h1 class="fqn">Macro <a href="index.html">clap</a>::<wbr><a class="macro" href="#">arg_enum</a><button id="copy-path" onclick="copy_path(this)" title="Copy item path to clipboard"><img src="../clipboard.svg" width="19" height="18" alt="Copy item path"></button></h1><span class="out-of-band"><a class="srclink" href="../src/clap/macros.rs.html#317-418">source</a> · <a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs">[<span class="inner">−</span>]</a></span></div><div class="item-decl"><div class="example-wrap"><pre class="rust macro"><code><span class="macro">macro_rules! </span>arg_enum { |
| (@as_item $(<span class="macro-nonterminal">$i</span>:item)<span class="kw-2">*</span>) => { ... }; |
| (@impls ( $(<span class="macro-nonterminal">$tts</span>:tt)* ) -> (<span class="macro-nonterminal">$e</span>:ident, $(<span class="macro-nonterminal">$v</span>:ident),+)) => { ... }; |
| ($(<span class="attribute">#[$(<span class="macro-nonterminal">$m</span>:meta),+]</span>)+ <span class="kw">pub enum </span><span class="macro-nonterminal">$e</span>:ident { $(<span class="macro-nonterminal">$v</span>:ident $(=<span class="macro-nonterminal">$val</span>:expr)<span class="kw-2">*</span>,)+ } ) => { ... }; |
| ($(<span class="attribute">#[$(<span class="macro-nonterminal">$m</span>:meta),+]</span>)+ <span class="kw">pub enum </span><span class="macro-nonterminal">$e</span>:ident { $(<span class="macro-nonterminal">$v</span>:ident $(=<span class="macro-nonterminal">$val</span>:expr)<span class="kw-2">*</span>),+ } ) => { ... }; |
| ($(<span class="attribute">#[$(<span class="macro-nonterminal">$m</span>:meta),+]</span>)+ <span class="kw">enum </span><span class="macro-nonterminal">$e</span>:ident { $(<span class="macro-nonterminal">$v</span>:ident $(=<span class="macro-nonterminal">$val</span>:expr)<span class="kw-2">*</span>,)+ } ) => { ... }; |
| ($(<span class="attribute">#[$(<span class="macro-nonterminal">$m</span>:meta),+]</span>)+ <span class="kw">enum </span><span class="macro-nonterminal">$e</span>:ident { $(<span class="macro-nonterminal">$v</span>:ident $(=<span class="macro-nonterminal">$val</span>:expr)<span class="kw-2">*</span>),+ } ) => { ... }; |
| (<span class="kw">pub enum </span><span class="macro-nonterminal">$e</span>:ident { $(<span class="macro-nonterminal">$v</span>:ident $(=<span class="macro-nonterminal">$val</span>:expr)<span class="kw-2">*</span>,)+ } ) => { ... }; |
| (<span class="kw">pub enum </span><span class="macro-nonterminal">$e</span>:ident { $(<span class="macro-nonterminal">$v</span>:ident $(=<span class="macro-nonterminal">$val</span>:expr)<span class="kw-2">*</span>),+ } ) => { ... }; |
| (<span class="kw">enum </span><span class="macro-nonterminal">$e</span>:ident { $(<span class="macro-nonterminal">$v</span>:ident $(=<span class="macro-nonterminal">$val</span>:expr)<span class="kw-2">*</span>,)+ } ) => { ... }; |
| (<span class="kw">enum </span><span class="macro-nonterminal">$e</span>:ident { $(<span class="macro-nonterminal">$v</span>:ident $(=<span class="macro-nonterminal">$val</span>:expr)<span class="kw-2">*</span>),+ } ) => { ... }; |
| }</code></pre></div> |
| </div><details class="rustdoc-toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Convenience macro to generate more complete enums with variants to be used as a type when |
| parsing arguments. This enum also provides a <code>variants()</code> function which can be used to |
| retrieve a <code>Vec<&'static str></code> of the variant names, as well as implementing <a href="https://doc.rust-lang.org/std/str/trait.FromStr.html"><code>FromStr</code></a> and |
| <a href="https://doc.rust-lang.org/std/fmt/trait.Display.html"><code>Display</code></a> automatically.</p> |
| <p><strong>NOTE:</strong> Case insensitivity is supported for ASCII characters only. It’s highly recommended to |
| use <a href="./struct.Arg.html#method.case_insensitive"><code>Arg::case_insensitive(true)</code></a> for args that will be used with these enums</p> |
| <p><strong>NOTE:</strong> This macro automatically implements <a href="https://doc.rust-lang.org/std/str/trait.FromStr.html"><code>std::str::FromStr</code></a> and <a href="https://doc.rust-lang.org/std/fmt/trait.Display.html"><code>std::fmt::Display</code></a></p> |
| <p><strong>NOTE:</strong> These enums support pub (or not) and uses of the <code>#[derive()]</code> traits</p> |
| <h2 id="examples"><a href="#examples">Examples</a></h2> |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="macro">arg_enum!</span>{ |
| <span class="attribute">#[derive(PartialEq, Debug)] |
| </span><span class="kw">pub enum </span>Foo { |
| Bar, |
| Baz, |
| Qux |
| } |
| } |
| <span class="comment">// Foo enum can now be used via Foo::Bar, or Foo::Baz, etc |
| // and implements std::str::FromStr to use with the value_t! macros |
| </span><span class="kw">fn </span>main() { |
| <span class="kw">let </span>m = App::new(<span class="string">"app"</span>) |
| .arg(Arg::from_usage(<span class="string">"<foo> 'the foo'"</span>) |
| .possible_values(<span class="kw-2">&</span>Foo::variants()) |
| .case_insensitive(<span class="bool-val">true</span>)) |
| .get_matches_from(<span class="macro">vec!</span>[ |
| <span class="string">"app"</span>, <span class="string">"baz" |
| </span>]); |
| <span class="kw">let </span>f = <span class="macro">value_t!</span>(m, <span class="string">"foo"</span>, Foo).unwrap_or_else(|e| e.exit()); |
| |
| <span class="macro">assert_eq!</span>(f, Foo::Baz); |
| }</code></pre></div> |
| </div></details></section></div></main><div id="rustdoc-vars" data-root-path="../" data-current-crate="clap" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
