| <!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="Wraps a function, turning it into a parser."><meta name="keywords" content="rust, rustlang, rust-lang, parser"><title>parser in combine - 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 fn"><!--[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="../combine/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="../combine/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 combine</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">Function <a href="index.html">combine</a>::<wbr><a class="fn" href="#">parser</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/combine/parser/function.rs.html#61-67">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"><pre class="rust fn"><code>pub fn parser<Input, O, F>(f: F) -> <a class="struct" href="parser/function/struct.FnParser.html" title="struct combine::parser::function::FnParser">FnParser</a><Input, F><span class="where fmt-newline">where<br> Input: <a class="trait" href="trait.Stream.html" title="trait combine::Stream">Stream</a>,<br> F: FnMut(&mut Input) -> <a class="type" href="type.StdParseResult.html" title="type combine::StdParseResult">StdParseResult</a><O, Input>,</span></code></pre></div><details class="rustdoc-toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Wraps a function, turning it into a parser.</p> |
| <p>Mainly needed to turn closures into parsers as function types can be casted to function pointers |
| to make them usable as a parser.</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">extern crate </span>combine; |
| <span class="kw">let </span><span class="kw-2">mut </span>even_digit = parser(|input| { |
| <span class="comment">// Help type inference out |
| </span><span class="kw">let _</span>: <span class="kw-2">&mut </span>easy::Stream<<span class="kw-2">&</span>str> = input; |
| <span class="kw">let </span>position = input.position(); |
| <span class="kw">let </span>(char_digit, committed) = digit().parse_stream(input).into_result()<span class="question-mark">?</span>; |
| <span class="kw">let </span>d = (char_digit <span class="kw">as </span>i32) - (<span class="string">'0' </span><span class="kw">as </span>i32); |
| <span class="kw">if </span>d % <span class="number">2 </span>== <span class="number">0 </span>{ |
| <span class="prelude-val">Ok</span>((d, committed)) |
| } |
| <span class="kw">else </span>{ |
| <span class="comment">//Return an empty error since we only tested the first token of the stream |
| </span><span class="kw">let </span>errors = easy::Errors::new( |
| position, |
| StreamError::expected(<span class="string">"even number"</span>) |
| ); |
| <span class="prelude-val">Err</span>(Commit::Peek(errors.into())) |
| } |
| }); |
| <span class="kw">let </span>result = even_digit |
| .easy_parse(<span class="string">"8"</span>) |
| .map(|x| x.<span class="number">0</span>); |
| <span class="macro">assert_eq!</span>(result, <span class="prelude-val">Ok</span>(<span class="number">8</span>));</code></pre></div> |
| </div></details></section></div></main><div id="rustdoc-vars" data-root-path="../" data-current-crate="combine" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |