| <!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="Source of the Rust file `/root/.cargo/registry/src/github.com-1ecc6299db9ec823/itertools-0.10.5/src/process_results_impl.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>process_results_impl.rs - source</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="../../source-script.js"></script><script defer src="../../source-files.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 source"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><a class="sidebar-logo" href="../../itertools/index.html"><div class="logo-container"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></div></a></nav><main><div class="width-limiter"><nav class="sub"><a class="sub-logo-container" href="../../itertools/index.html"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></a><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="example-wrap"><pre class="src-line-numbers"><span id="1">1</span> |
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| </pre><pre class="rust"><code> |
| <span class="doccomment">/// An iterator that produces only the `T` values as long as the |
| /// inner iterator produces `Ok(T)`. |
| /// |
| /// Used by [`process_results`](crate::process_results), see its docs |
| /// for more information. |
| </span><span class="attribute">#[must_use = <span class="string">"iterator adaptors are lazy and do nothing unless consumed"</span>] |
| #[derive(Debug)] |
| </span><span class="kw">pub struct </span>ProcessResults<<span class="lifetime">'a</span>, I, E: <span class="lifetime">'a</span>> { |
| error: <span class="kw-2">&</span><span class="lifetime">'a </span><span class="kw-2">mut </span><span class="prelude-ty">Result</span><(), E>, |
| iter: I, |
| } |
| |
| <span class="kw">impl</span><<span class="lifetime">'a</span>, I, T, E> Iterator <span class="kw">for </span>ProcessResults<<span class="lifetime">'a</span>, I, E> |
| <span class="kw">where </span>I: Iterator<Item = <span class="prelude-ty">Result</span><T, E>> |
| { |
| <span class="kw">type </span>Item = T; |
| |
| <span class="kw">fn </span>next(<span class="kw-2">&mut </span><span class="self">self</span>) -> <span class="prelude-ty">Option</span><<span class="self">Self</span>::Item> { |
| <span class="kw">match </span><span class="self">self</span>.iter.next() { |
| <span class="prelude-val">Some</span>(<span class="prelude-val">Ok</span>(x)) => <span class="prelude-val">Some</span>(x), |
| <span class="prelude-val">Some</span>(<span class="prelude-val">Err</span>(e)) => { |
| <span class="kw-2">*</span><span class="self">self</span>.error = <span class="prelude-val">Err</span>(e); |
| <span class="prelude-val">None |
| </span>} |
| <span class="prelude-val">None </span>=> <span class="prelude-val">None</span>, |
| } |
| } |
| |
| <span class="kw">fn </span>size_hint(<span class="kw-2">&</span><span class="self">self</span>) -> (usize, <span class="prelude-ty">Option</span><usize>) { |
| (<span class="number">0</span>, <span class="self">self</span>.iter.size_hint().<span class="number">1</span>) |
| } |
| |
| <span class="kw">fn </span>fold<B, F>(<span class="kw-2">mut </span><span class="self">self</span>, init: B, <span class="kw-2">mut </span>f: F) -> B |
| <span class="kw">where |
| </span><span class="self">Self</span>: Sized, |
| F: FnMut(B, <span class="self">Self</span>::Item) -> B, |
| { |
| <span class="kw">let </span>error = <span class="self">self</span>.error; |
| <span class="self">self</span>.iter |
| .try_fold(init, |acc, opt| <span class="kw">match </span>opt { |
| <span class="prelude-val">Ok</span>(x) => <span class="prelude-val">Ok</span>(f(acc, x)), |
| <span class="prelude-val">Err</span>(e) => { |
| <span class="kw-2">*</span>error = <span class="prelude-val">Err</span>(e); |
| <span class="prelude-val">Err</span>(acc) |
| } |
| }) |
| .unwrap_or_else(|e| e) |
| } |
| } |
| |
| <span class="doccomment">/// “Lift” a function of the values of an iterator so that it can process |
| /// an iterator of `Result` values instead. |
| /// |
| /// `iterable` is an iterator or iterable with `Result<T, E>` elements, where |
| /// `T` is the value type and `E` the error type. |
| /// |
| /// `processor` is a closure that receives an adapted version of the iterable |
| /// as the only argument — the adapted iterator produces elements of type `T`, |
| /// as long as the original iterator produces `Ok` values. |
| /// |
| /// If the original iterable produces an error at any point, the adapted |
| /// iterator ends and the `process_results` function will return the |
| /// error iself. |
| /// |
| /// Otherwise, the return value from the closure is returned wrapped |
| /// inside `Ok`. |
| /// |
| /// # Example |
| /// |
| /// ``` |
| /// use itertools::process_results; |
| /// |
| /// type R = Result<i32, &'static str>; |
| /// |
| /// let first_values: Vec<R> = vec![Ok(1), Ok(0), Ok(3)]; |
| /// let second_values: Vec<R> = vec![Ok(2), Ok(1), Err("overflow")]; |
| /// |
| /// // “Lift” the iterator .max() method to work on the values in Results using process_results |
| /// |
| /// let first_max = process_results(first_values, |iter| iter.max().unwrap_or(0)); |
| /// let second_max = process_results(second_values, |iter| iter.max().unwrap_or(0)); |
| /// |
| /// assert_eq!(first_max, Ok(3)); |
| /// assert!(second_max.is_err()); |
| /// ``` |
| </span><span class="kw">pub fn </span>process_results<I, F, T, E, R>(iterable: I, processor: F) -> <span class="prelude-ty">Result</span><R, E> |
| <span class="kw">where </span>I: IntoIterator<Item = <span class="prelude-ty">Result</span><T, E>>, |
| F: FnOnce(ProcessResults<I::IntoIter, E>) -> R |
| { |
| <span class="kw">let </span>iter = iterable.into_iter(); |
| <span class="kw">let </span><span class="kw-2">mut </span>error = <span class="prelude-val">Ok</span>(()); |
| |
| <span class="kw">let </span>result = processor(ProcessResults { error: <span class="kw-2">&mut </span>error, iter }); |
| |
| error.map(|<span class="kw">_</span>| result) |
| } |
| </code></pre></div> |
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