| <!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/adaptors/coalesce.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>coalesce.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="kw">use </span>std::fmt; |
| <span class="kw">use </span>std::iter::FusedIterator; |
| |
| <span class="kw">use </span><span class="kw">crate</span>::size_hint; |
| |
| <span class="attribute">#[must_use = <span class="string">"iterator adaptors are lazy and do nothing unless consumed"</span>] |
| </span><span class="kw">pub struct </span>CoalesceBy<I, F, T> |
| <span class="kw">where |
| </span>I: Iterator, |
| { |
| iter: I, |
| last: <span class="prelude-ty">Option</span><T>, |
| f: F, |
| } |
| |
| <span class="kw">impl</span><I: Clone, F: Clone, T: Clone> Clone <span class="kw">for </span>CoalesceBy<I, F, T> |
| <span class="kw">where |
| </span>I: Iterator, |
| { |
| <span class="macro">clone_fields!</span>(last, iter, f); |
| } |
| |
| <span class="kw">impl</span><I, F, T> fmt::Debug <span class="kw">for </span>CoalesceBy<I, F, T> |
| <span class="kw">where |
| </span>I: Iterator + fmt::Debug, |
| T: fmt::Debug, |
| { |
| <span class="macro">debug_fmt_fields!</span>(CoalesceBy, iter); |
| } |
| |
| <span class="kw">pub trait </span>CoalescePredicate<Item, T> { |
| <span class="kw">fn </span>coalesce_pair(<span class="kw-2">&mut </span><span class="self">self</span>, t: T, item: Item) -> <span class="prelude-ty">Result</span><T, (T, T)>; |
| } |
| |
| <span class="kw">impl</span><I, F, T> Iterator <span class="kw">for </span>CoalesceBy<I, F, T> |
| <span class="kw">where |
| </span>I: Iterator, |
| F: CoalescePredicate<I::Item, T>, |
| { |
| <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="comment">// this fuses the iterator |
| </span><span class="kw">let </span>last = <span class="self">self</span>.last.take()<span class="question-mark">?</span>; |
| |
| <span class="kw">let </span>self_last = <span class="kw-2">&mut </span><span class="self">self</span>.last; |
| <span class="kw">let </span>self_f = <span class="kw-2">&mut </span><span class="self">self</span>.f; |
| <span class="prelude-val">Some</span>( |
| <span class="self">self</span>.iter |
| .try_fold(last, |last, next| <span class="kw">match </span>self_f.coalesce_pair(last, next) { |
| <span class="prelude-val">Ok</span>(joined) => <span class="prelude-val">Ok</span>(joined), |
| <span class="prelude-val">Err</span>((last_, next_)) => { |
| <span class="kw-2">*</span>self_last = <span class="prelude-val">Some</span>(next_); |
| <span class="prelude-val">Err</span>(last_) |
| } |
| }) |
| .unwrap_or_else(|x| x), |
| ) |
| } |
| |
| <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="kw">let </span>(low, hi) = size_hint::add_scalar(<span class="self">self</span>.iter.size_hint(), <span class="self">self</span>.last.is_some() <span class="kw">as </span>usize); |
| ((low > <span class="number">0</span>) <span class="kw">as </span>usize, hi) |
| } |
| |
| <span class="kw">fn </span>fold<Acc, FnAcc>(<span class="self">self</span>, acc: Acc, <span class="kw-2">mut </span>fn_acc: FnAcc) -> Acc |
| <span class="kw">where |
| </span>FnAcc: FnMut(Acc, <span class="self">Self</span>::Item) -> Acc, |
| { |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(last) = <span class="self">self</span>.last { |
| <span class="kw">let </span><span class="kw-2">mut </span>f = <span class="self">self</span>.f; |
| <span class="kw">let </span>(last, acc) = <span class="self">self</span>.iter.fold((last, acc), |(last, acc), elt| { |
| <span class="kw">match </span>f.coalesce_pair(last, elt) { |
| <span class="prelude-val">Ok</span>(joined) => (joined, acc), |
| <span class="prelude-val">Err</span>((last_, next_)) => (next_, fn_acc(acc, last_)), |
| } |
| }); |
| fn_acc(acc, last) |
| } <span class="kw">else </span>{ |
| acc |
| } |
| } |
| } |
| |
| <span class="kw">impl</span><I: Iterator, F: CoalescePredicate<I::Item, T>, T> FusedIterator <span class="kw">for </span>CoalesceBy<I, F, T> {} |
| |
| <span class="doccomment">/// An iterator adaptor that may join together adjacent elements. |
| /// |
| /// See [`.coalesce()`](crate::Itertools::coalesce) for more information. |
| </span><span class="kw">pub type </span>Coalesce<I, F> = CoalesceBy<I, F, <I <span class="kw">as </span>Iterator>::Item>; |
| |
| <span class="kw">impl</span><F, Item, T> CoalescePredicate<Item, T> <span class="kw">for </span>F |
| <span class="kw">where |
| </span>F: FnMut(T, Item) -> <span class="prelude-ty">Result</span><T, (T, T)>, |
| { |
| <span class="kw">fn </span>coalesce_pair(<span class="kw-2">&mut </span><span class="self">self</span>, t: T, item: Item) -> <span class="prelude-ty">Result</span><T, (T, T)> { |
| <span class="self">self</span>(t, item) |
| } |
| } |
| |
| <span class="doccomment">/// Create a new `Coalesce`. |
| </span><span class="kw">pub fn </span>coalesce<I, F>(<span class="kw-2">mut </span>iter: I, f: F) -> Coalesce<I, F> |
| <span class="kw">where |
| </span>I: Iterator, |
| { |
| Coalesce { |
| last: iter.next(), |
| iter, |
| f, |
| } |
| } |
| |
| <span class="doccomment">/// An iterator adaptor that removes repeated duplicates, determining equality using a comparison function. |
| /// |
| /// See [`.dedup_by()`](crate::Itertools::dedup_by) or [`.dedup()`](crate::Itertools::dedup) for more information. |
| </span><span class="kw">pub type </span>DedupBy<I, Pred> = CoalesceBy<I, DedupPred2CoalescePred<Pred>, <I <span class="kw">as </span>Iterator>::Item>; |
| |
| <span class="attribute">#[derive(Clone)] |
| </span><span class="kw">pub struct </span>DedupPred2CoalescePred<DP>(DP); |
| |
| <span class="kw">impl</span><DP> fmt::Debug <span class="kw">for </span>DedupPred2CoalescePred<DP> { |
| <span class="macro">debug_fmt_fields!</span>(DedupPred2CoalescePred,); |
| } |
| |
| <span class="kw">pub trait </span>DedupPredicate<T> { |
| <span class="comment">// TODO replace by Fn(&T, &T)->bool once Rust supports it |
| </span><span class="kw">fn </span>dedup_pair(<span class="kw-2">&mut </span><span class="self">self</span>, a: <span class="kw-2">&</span>T, b: <span class="kw-2">&</span>T) -> bool; |
| } |
| |
| <span class="kw">impl</span><DP, T> CoalescePredicate<T, T> <span class="kw">for </span>DedupPred2CoalescePred<DP> |
| <span class="kw">where |
| </span>DP: DedupPredicate<T>, |
| { |
| <span class="kw">fn </span>coalesce_pair(<span class="kw-2">&mut </span><span class="self">self</span>, t: T, item: T) -> <span class="prelude-ty">Result</span><T, (T, T)> { |
| <span class="kw">if </span><span class="self">self</span>.<span class="number">0</span>.dedup_pair(<span class="kw-2">&</span>t, <span class="kw-2">&</span>item) { |
| <span class="prelude-val">Ok</span>(t) |
| } <span class="kw">else </span>{ |
| <span class="prelude-val">Err</span>((t, item)) |
| } |
| } |
| } |
| |
| <span class="attribute">#[derive(Clone, Debug)] |
| </span><span class="kw">pub struct </span>DedupEq; |
| |
| <span class="kw">impl</span><T: PartialEq> DedupPredicate<T> <span class="kw">for </span>DedupEq { |
| <span class="kw">fn </span>dedup_pair(<span class="kw-2">&mut </span><span class="self">self</span>, a: <span class="kw-2">&</span>T, b: <span class="kw-2">&</span>T) -> bool { |
| a == b |
| } |
| } |
| |
| <span class="kw">impl</span><T, F: FnMut(<span class="kw-2">&</span>T, <span class="kw-2">&</span>T) -> bool> DedupPredicate<T> <span class="kw">for </span>F { |
| <span class="kw">fn </span>dedup_pair(<span class="kw-2">&mut </span><span class="self">self</span>, a: <span class="kw-2">&</span>T, b: <span class="kw-2">&</span>T) -> bool { |
| <span class="self">self</span>(a, b) |
| } |
| } |
| |
| <span class="doccomment">/// Create a new `DedupBy`. |
| </span><span class="kw">pub fn </span>dedup_by<I, Pred>(<span class="kw-2">mut </span>iter: I, dedup_pred: Pred) -> DedupBy<I, Pred> |
| <span class="kw">where |
| </span>I: Iterator, |
| { |
| DedupBy { |
| last: iter.next(), |
| iter, |
| f: DedupPred2CoalescePred(dedup_pred), |
| } |
| } |
| |
| <span class="doccomment">/// An iterator adaptor that removes repeated duplicates. |
| /// |
| /// See [`.dedup()`](crate::Itertools::dedup) for more information. |
| </span><span class="kw">pub type </span>Dedup<I> = DedupBy<I, DedupEq>; |
| |
| <span class="doccomment">/// Create a new `Dedup`. |
| </span><span class="kw">pub fn </span>dedup<I>(iter: I) -> Dedup<I> |
| <span class="kw">where |
| </span>I: Iterator, |
| { |
| dedup_by(iter, DedupEq) |
| } |
| |
| <span class="doccomment">/// An iterator adaptor that removes repeated duplicates, while keeping a count of how many |
| /// repeated elements were present. This will determine equality using a comparison function. |
| /// |
| /// See [`.dedup_by_with_count()`](crate::Itertools::dedup_by_with_count) or |
| /// [`.dedup_with_count()`](crate::Itertools::dedup_with_count) for more information. |
| </span><span class="kw">pub type </span>DedupByWithCount<I, Pred> = |
| CoalesceBy<I, DedupPredWithCount2CoalescePred<Pred>, (usize, <I <span class="kw">as </span>Iterator>::Item)>; |
| |
| <span class="attribute">#[derive(Clone, Debug)] |
| </span><span class="kw">pub struct </span>DedupPredWithCount2CoalescePred<DP>(DP); |
| |
| <span class="kw">impl</span><DP, T> CoalescePredicate<T, (usize, T)> <span class="kw">for </span>DedupPredWithCount2CoalescePred<DP> |
| <span class="kw">where |
| </span>DP: DedupPredicate<T>, |
| { |
| <span class="kw">fn </span>coalesce_pair( |
| <span class="kw-2">&mut </span><span class="self">self</span>, |
| (c, t): (usize, T), |
| item: T, |
| ) -> <span class="prelude-ty">Result</span><(usize, T), ((usize, T), (usize, T))> { |
| <span class="kw">if </span><span class="self">self</span>.<span class="number">0</span>.dedup_pair(<span class="kw-2">&</span>t, <span class="kw-2">&</span>item) { |
| <span class="prelude-val">Ok</span>((c + <span class="number">1</span>, t)) |
| } <span class="kw">else </span>{ |
| <span class="prelude-val">Err</span>(((c, t), (<span class="number">1</span>, item))) |
| } |
| } |
| } |
| |
| <span class="doccomment">/// An iterator adaptor that removes repeated duplicates, while keeping a count of how many |
| /// repeated elements were present. |
| /// |
| /// See [`.dedup_with_count()`](crate::Itertools::dedup_with_count) for more information. |
| </span><span class="kw">pub type </span>DedupWithCount<I> = DedupByWithCount<I, DedupEq>; |
| |
| <span class="doccomment">/// Create a new `DedupByWithCount`. |
| </span><span class="kw">pub fn </span>dedup_by_with_count<I, Pred>(<span class="kw-2">mut </span>iter: I, dedup_pred: Pred) -> DedupByWithCount<I, Pred> |
| <span class="kw">where |
| </span>I: Iterator, |
| { |
| DedupByWithCount { |
| last: iter.next().map(|v| (<span class="number">1</span>, v)), |
| iter, |
| f: DedupPredWithCount2CoalescePred(dedup_pred), |
| } |
| } |
| |
| <span class="doccomment">/// Create a new `DedupWithCount`. |
| </span><span class="kw">pub fn </span>dedup_with_count<I>(iter: I) -> DedupWithCount<I> |
| <span class="kw">where |
| </span>I: Iterator, |
| { |
| dedup_by_with_count(iter, DedupEq) |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../../" data-current-crate="itertools" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
