Sophie

Sophie

distrib > Mageia > 6 > armv7hl > media > core-updates > by-pkgid > 4e2dbb669434a7691662cb2f0ad38972 > files > 11561

rust-doc-1.28.0-1.mga6.armv7hl.rpm

<!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 to the Rust file `libcore/iter/sources.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>sources.rs.html -- source</title><link rel="stylesheet" type="text/css" href="../../../normalize.css"><link rel="stylesheet" type="text/css" href="../../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" type="text/css" href="../../../dark.css"><link rel="stylesheet" type="text/css" href="../../../light.css" id="themeStyle"><script src="../../../storage.js"></script><link rel="shortcut icon" href="https://doc.rust-lang.org/favicon.ico"></head><body class="rustdoc source"><!--[if lte IE 8]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><div class="sidebar-menu">&#9776;</div><a href='../../../core/index.html'><img src='https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png' alt='logo' width='100'></a></nav><div class="theme-picker"><button id="theme-picker" aria-label="Pick another theme!"><img src="../../../brush.svg" width="18" alt="Pick another theme!"></button><div id="theme-choices"></div></div><script src="../../../theme.js"></script><nav class="sub"><form class="search-form js-only"><div class="search-container"><input class="search-input" name="search" autocomplete="off" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><a id="settings-menu" href="../../../settings.html"><img src="../../../wheel.svg" width="18" alt="Change settings"></a></div></form></nav><section id="main" class="content"><pre class="line-numbers"><span id="1">  1</span>
<span id="2">  2</span>
<span id="3">  3</span>
<span id="4">  4</span>
<span id="5">  5</span>
<span id="6">  6</span>
<span id="7">  7</span>
<span id="8">  8</span>
<span id="9">  9</span>
<span id="10"> 10</span>
<span id="11"> 11</span>
<span id="12"> 12</span>
<span id="13"> 13</span>
<span id="14"> 14</span>
<span id="15"> 15</span>
<span id="16"> 16</span>
<span id="17"> 17</span>
<span id="18"> 18</span>
<span id="19"> 19</span>
<span id="20"> 20</span>
<span id="21"> 21</span>
<span id="22"> 22</span>
<span id="23"> 23</span>
<span id="24"> 24</span>
<span id="25"> 25</span>
<span id="26"> 26</span>
<span id="27"> 27</span>
<span id="28"> 28</span>
<span id="29"> 29</span>
<span id="30"> 30</span>
<span id="31"> 31</span>
<span id="32"> 32</span>
<span id="33"> 33</span>
<span id="34"> 34</span>
<span id="35"> 35</span>
<span id="36"> 36</span>
<span id="37"> 37</span>
<span id="38"> 38</span>
<span id="39"> 39</span>
<span id="40"> 40</span>
<span id="41"> 41</span>
<span id="42"> 42</span>
<span id="43"> 43</span>
<span id="44"> 44</span>
<span id="45"> 45</span>
<span id="46"> 46</span>
<span id="47"> 47</span>
<span id="48"> 48</span>
<span id="49"> 49</span>
<span id="50"> 50</span>
<span id="51"> 51</span>
<span id="52"> 52</span>
<span id="53"> 53</span>
<span id="54"> 54</span>
<span id="55"> 55</span>
<span id="56"> 56</span>
<span id="57"> 57</span>
<span id="58"> 58</span>
<span id="59"> 59</span>
<span id="60"> 60</span>
<span id="61"> 61</span>
<span id="62"> 62</span>
<span id="63"> 63</span>
<span id="64"> 64</span>
<span id="65"> 65</span>
<span id="66"> 66</span>
<span id="67"> 67</span>
<span id="68"> 68</span>
<span id="69"> 69</span>
<span id="70"> 70</span>
<span id="71"> 71</span>
<span id="72"> 72</span>
<span id="73"> 73</span>
<span id="74"> 74</span>
<span id="75"> 75</span>
<span id="76"> 76</span>
<span id="77"> 77</span>
<span id="78"> 78</span>
<span id="79"> 79</span>
<span id="80"> 80</span>
<span id="81"> 81</span>
<span id="82"> 82</span>
<span id="83"> 83</span>
<span id="84"> 84</span>
<span id="85"> 85</span>
<span id="86"> 86</span>
<span id="87"> 87</span>
<span id="88"> 88</span>
<span id="89"> 89</span>
<span id="90"> 90</span>
<span id="91"> 91</span>
<span id="92"> 92</span>
<span id="93"> 93</span>
<span id="94"> 94</span>
<span id="95"> 95</span>
<span id="96"> 96</span>
<span id="97"> 97</span>
<span id="98"> 98</span>
<span id="99"> 99</span>
<span id="100">100</span>
<span id="101">101</span>
<span id="102">102</span>
<span id="103">103</span>
<span id="104">104</span>
<span id="105">105</span>
<span id="106">106</span>
<span id="107">107</span>
<span id="108">108</span>
<span id="109">109</span>
<span id="110">110</span>
<span id="111">111</span>
<span id="112">112</span>
<span id="113">113</span>
<span id="114">114</span>
<span id="115">115</span>
<span id="116">116</span>
<span id="117">117</span>
<span id="118">118</span>
<span id="119">119</span>
<span id="120">120</span>
<span id="121">121</span>
<span id="122">122</span>
<span id="123">123</span>
<span id="124">124</span>
<span id="125">125</span>
<span id="126">126</span>
<span id="127">127</span>
<span id="128">128</span>
<span id="129">129</span>
<span id="130">130</span>
<span id="131">131</span>
<span id="132">132</span>
<span id="133">133</span>
<span id="134">134</span>
<span id="135">135</span>
<span id="136">136</span>
<span id="137">137</span>
<span id="138">138</span>
<span id="139">139</span>
<span id="140">140</span>
<span id="141">141</span>
<span id="142">142</span>
<span id="143">143</span>
<span id="144">144</span>
<span id="145">145</span>
<span id="146">146</span>
<span id="147">147</span>
<span id="148">148</span>
<span id="149">149</span>
<span id="150">150</span>
<span id="151">151</span>
<span id="152">152</span>
<span id="153">153</span>
<span id="154">154</span>
<span id="155">155</span>
<span id="156">156</span>
<span id="157">157</span>
<span id="158">158</span>
<span id="159">159</span>
<span id="160">160</span>
<span id="161">161</span>
<span id="162">162</span>
<span id="163">163</span>
<span id="164">164</span>
<span id="165">165</span>
<span id="166">166</span>
<span id="167">167</span>
<span id="168">168</span>
<span id="169">169</span>
<span id="170">170</span>
<span id="171">171</span>
<span id="172">172</span>
<span id="173">173</span>
<span id="174">174</span>
<span id="175">175</span>
<span id="176">176</span>
<span id="177">177</span>
<span id="178">178</span>
<span id="179">179</span>
<span id="180">180</span>
<span id="181">181</span>
<span id="182">182</span>
<span id="183">183</span>
<span id="184">184</span>
<span id="185">185</span>
<span id="186">186</span>
<span id="187">187</span>
<span id="188">188</span>
<span id="189">189</span>
<span id="190">190</span>
<span id="191">191</span>
<span id="192">192</span>
<span id="193">193</span>
<span id="194">194</span>
<span id="195">195</span>
<span id="196">196</span>
<span id="197">197</span>
<span id="198">198</span>
<span id="199">199</span>
<span id="200">200</span>
<span id="201">201</span>
<span id="202">202</span>
<span id="203">203</span>
<span id="204">204</span>
<span id="205">205</span>
<span id="206">206</span>
<span id="207">207</span>
<span id="208">208</span>
<span id="209">209</span>
<span id="210">210</span>
<span id="211">211</span>
<span id="212">212</span>
<span id="213">213</span>
<span id="214">214</span>
<span id="215">215</span>
<span id="216">216</span>
<span id="217">217</span>
<span id="218">218</span>
<span id="219">219</span>
<span id="220">220</span>
<span id="221">221</span>
<span id="222">222</span>
<span id="223">223</span>
<span id="224">224</span>
<span id="225">225</span>
<span id="226">226</span>
<span id="227">227</span>
<span id="228">228</span>
<span id="229">229</span>
<span id="230">230</span>
<span id="231">231</span>
<span id="232">232</span>
<span id="233">233</span>
<span id="234">234</span>
<span id="235">235</span>
<span id="236">236</span>
<span id="237">237</span>
<span id="238">238</span>
<span id="239">239</span>
<span id="240">240</span>
<span id="241">241</span>
<span id="242">242</span>
<span id="243">243</span>
<span id="244">244</span>
<span id="245">245</span>
<span id="246">246</span>
<span id="247">247</span>
<span id="248">248</span>
<span id="249">249</span>
<span id="250">250</span>
<span id="251">251</span>
<span id="252">252</span>
<span id="253">253</span>
<span id="254">254</span>
<span id="255">255</span>
<span id="256">256</span>
<span id="257">257</span>
<span id="258">258</span>
<span id="259">259</span>
<span id="260">260</span>
<span id="261">261</span>
<span id="262">262</span>
<span id="263">263</span>
<span id="264">264</span>
<span id="265">265</span>
<span id="266">266</span>
<span id="267">267</span>
<span id="268">268</span>
<span id="269">269</span>
<span id="270">270</span>
<span id="271">271</span>
<span id="272">272</span>
<span id="273">273</span>
<span id="274">274</span>
<span id="275">275</span>
<span id="276">276</span>
<span id="277">277</span>
<span id="278">278</span>
<span id="279">279</span>
<span id="280">280</span>
<span id="281">281</span>
<span id="282">282</span>
<span id="283">283</span>
<span id="284">284</span>
<span id="285">285</span>
<span id="286">286</span>
<span id="287">287</span>
<span id="288">288</span>
<span id="289">289</span>
<span id="290">290</span>
<span id="291">291</span>
<span id="292">292</span>
<span id="293">293</span>
<span id="294">294</span>
<span id="295">295</span>
<span id="296">296</span>
<span id="297">297</span>
<span id="298">298</span>
<span id="299">299</span>
<span id="300">300</span>
<span id="301">301</span>
<span id="302">302</span>
<span id="303">303</span>
<span id="304">304</span>
<span id="305">305</span>
<span id="306">306</span>
<span id="307">307</span>
<span id="308">308</span>
<span id="309">309</span>
<span id="310">310</span>
<span id="311">311</span>
<span id="312">312</span>
<span id="313">313</span>
<span id="314">314</span>
<span id="315">315</span>
<span id="316">316</span>
<span id="317">317</span>
<span id="318">318</span>
<span id="319">319</span>
<span id="320">320</span>
<span id="321">321</span>
<span id="322">322</span>
<span id="323">323</span>
<span id="324">324</span>
<span id="325">325</span>
<span id="326">326</span>
<span id="327">327</span>
<span id="328">328</span>
<span id="329">329</span>
<span id="330">330</span>
<span id="331">331</span>
<span id="332">332</span>
<span id="333">333</span>
<span id="334">334</span>
<span id="335">335</span>
<span id="336">336</span>
<span id="337">337</span>
<span id="338">338</span>
<span id="339">339</span>
<span id="340">340</span>
<span id="341">341</span>
<span id="342">342</span>
<span id="343">343</span>
<span id="344">344</span>
<span id="345">345</span>
<span id="346">346</span>
<span id="347">347</span>
<span id="348">348</span>
<span id="349">349</span>
<span id="350">350</span>
<span id="351">351</span>
<span id="352">352</span>
<span id="353">353</span>
<span id="354">354</span>
<span id="355">355</span>
<span id="356">356</span>
<span id="357">357</span>
<span id="358">358</span>
<span id="359">359</span>
<span id="360">360</span>
<span id="361">361</span>
<span id="362">362</span>
<span id="363">363</span>
<span id="364">364</span>
<span id="365">365</span>
<span id="366">366</span>
<span id="367">367</span>
<span id="368">368</span>
<span id="369">369</span>
<span id="370">370</span>
<span id="371">371</span>
<span id="372">372</span>
<span id="373">373</span>
<span id="374">374</span>
<span id="375">375</span>
<span id="376">376</span>
<span id="377">377</span>
<span id="378">378</span>
<span id="379">379</span>
<span id="380">380</span>
<span id="381">381</span>
<span id="382">382</span>
<span id="383">383</span>
<span id="384">384</span>
<span id="385">385</span>
<span id="386">386</span>
<span id="387">387</span>
<span id="388">388</span>
</pre><pre class="rust ">
<span class="comment">// Copyright 2013-2016 The Rust Project Developers. See the COPYRIGHT</span>
<span class="comment">// file at the top-level directory of this distribution and at</span>
<span class="comment">// http://rust-lang.org/COPYRIGHT.</span>
<span class="comment">//</span>
<span class="comment">// Licensed under the Apache License, Version 2.0 &lt;LICENSE-APACHE or</span>
<span class="comment">// http://www.apache.org/licenses/LICENSE-2.0&gt; or the MIT license</span>
<span class="comment">// &lt;LICENSE-MIT or http://opensource.org/licenses/MIT&gt;, at your</span>
<span class="comment">// option. This file may not be copied, modified, or distributed</span>
<span class="comment">// except according to those terms.</span>

<span class="kw">use</span> <span class="ident">fmt</span>;
<span class="kw">use</span> <span class="ident">marker</span>;
<span class="kw">use</span> <span class="ident">usize</span>;

<span class="kw">use</span> <span class="kw">super</span>::{<span class="ident">FusedIterator</span>, <span class="ident">TrustedLen</span>};

<span class="doccomment">/// An iterator that repeats an element endlessly.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This `struct` is created by the [`repeat`] function. See its documentation for more.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// [`repeat`]: fn.repeat.html</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>)]</span>
<span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">&quot;rust1&quot;</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">&quot;1.0.0&quot;</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Repeat</span><span class="op">&lt;</span><span class="ident">A</span><span class="op">&gt;</span> {
    <span class="ident">element</span>: <span class="ident">A</span>
}

<span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">&quot;rust1&quot;</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">&quot;1.0.0&quot;</span>)]</span>
<span class="kw">impl</span><span class="op">&lt;</span><span class="ident">A</span>: <span class="ident">Clone</span><span class="op">&gt;</span> <span class="ident">Iterator</span> <span class="kw">for</span> <span class="ident">Repeat</span><span class="op">&lt;</span><span class="ident">A</span><span class="op">&gt;</span> {
    <span class="kw">type</span> <span class="ident">Item</span> <span class="op">=</span> <span class="ident">A</span>;

    <span class="attribute">#[<span class="ident">inline</span>]</span>
    <span class="kw">fn</span> <span class="ident">next</span>(<span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-&gt;</span> <span class="prelude-ty">Option</span><span class="op">&lt;</span><span class="ident">A</span><span class="op">&gt;</span> { <span class="prelude-val">Some</span>(<span class="self">self</span>.<span class="ident">element</span>.<span class="ident">clone</span>()) }
    <span class="attribute">#[<span class="ident">inline</span>]</span>
    <span class="kw">fn</span> <span class="ident">size_hint</span>(<span class="kw-2">&amp;</span><span class="self">self</span>) <span class="op">-&gt;</span> (<span class="ident">usize</span>, <span class="prelude-ty">Option</span><span class="op">&lt;</span><span class="ident">usize</span><span class="op">&gt;</span>) { (<span class="ident">usize</span>::<span class="ident">MAX</span>, <span class="prelude-val">None</span>) }
}

<span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">&quot;rust1&quot;</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">&quot;1.0.0&quot;</span>)]</span>
<span class="kw">impl</span><span class="op">&lt;</span><span class="ident">A</span>: <span class="ident">Clone</span><span class="op">&gt;</span> <span class="ident">DoubleEndedIterator</span> <span class="kw">for</span> <span class="ident">Repeat</span><span class="op">&lt;</span><span class="ident">A</span><span class="op">&gt;</span> {
    <span class="attribute">#[<span class="ident">inline</span>]</span>
    <span class="kw">fn</span> <span class="ident">next_back</span>(<span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-&gt;</span> <span class="prelude-ty">Option</span><span class="op">&lt;</span><span class="ident">A</span><span class="op">&gt;</span> { <span class="prelude-val">Some</span>(<span class="self">self</span>.<span class="ident">element</span>.<span class="ident">clone</span>()) }
}

<span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">&quot;fused&quot;</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">&quot;1.26.0&quot;</span>)]</span>
<span class="kw">impl</span><span class="op">&lt;</span><span class="ident">A</span>: <span class="ident">Clone</span><span class="op">&gt;</span> <span class="ident">FusedIterator</span> <span class="kw">for</span> <span class="ident">Repeat</span><span class="op">&lt;</span><span class="ident">A</span><span class="op">&gt;</span> {}

<span class="attribute">#[<span class="ident">unstable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">&quot;trusted_len&quot;</span>, <span class="ident">issue</span> <span class="op">=</span> <span class="string">&quot;37572&quot;</span>)]</span>
<span class="kw">unsafe</span> <span class="kw">impl</span><span class="op">&lt;</span><span class="ident">A</span>: <span class="ident">Clone</span><span class="op">&gt;</span> <span class="ident">TrustedLen</span> <span class="kw">for</span> <span class="ident">Repeat</span><span class="op">&lt;</span><span class="ident">A</span><span class="op">&gt;</span> {}

<span class="doccomment">/// Creates a new iterator that endlessly repeats a single element.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The `repeat()` function repeats a single value over and over and over and</span>
<span class="doccomment">/// over and over and 🔁.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Infinite iterators like `repeat()` are often used with adapters like</span>
<span class="doccomment">/// [`take`], in order to make them finite.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// [`take`]: trait.Iterator.html#method.take</span>
<span class="doccomment">///</span>
<span class="doccomment">/// If the element type of the iterator you need does not implement `Clone`,</span>
<span class="doccomment">/// or if you do not want to keep the repeated element in memory, you can</span>
<span class="doccomment">/// instead use the [`repeat_with`] function.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// [`repeat_with`]: fn.repeat_with.html</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Basic usage:</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use std::iter;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// // the number four 4ever:</span>
<span class="doccomment">/// let mut fours = iter::repeat(4);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(Some(4), fours.next());</span>
<span class="doccomment">/// assert_eq!(Some(4), fours.next());</span>
<span class="doccomment">/// assert_eq!(Some(4), fours.next());</span>
<span class="doccomment">/// assert_eq!(Some(4), fours.next());</span>
<span class="doccomment">/// assert_eq!(Some(4), fours.next());</span>
<span class="doccomment">///</span>
<span class="doccomment">/// // yup, still four</span>
<span class="doccomment">/// assert_eq!(Some(4), fours.next());</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Going finite with [`take`]:</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use std::iter;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// // that last example was too many fours. Let&#39;s only have four fours.</span>
<span class="doccomment">/// let mut four_fours = iter::repeat(4).take(4);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(Some(4), four_fours.next());</span>
<span class="doccomment">/// assert_eq!(Some(4), four_fours.next());</span>
<span class="doccomment">/// assert_eq!(Some(4), four_fours.next());</span>
<span class="doccomment">/// assert_eq!(Some(4), four_fours.next());</span>
<span class="doccomment">///</span>
<span class="doccomment">/// // ... and now we&#39;re done</span>
<span class="doccomment">/// assert_eq!(None, four_fours.next());</span>
<span class="doccomment">/// ```</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">&quot;rust1&quot;</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">&quot;1.0.0&quot;</span>)]</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">repeat</span><span class="op">&lt;</span><span class="ident">T</span>: <span class="ident">Clone</span><span class="op">&gt;</span>(<span class="ident">elt</span>: <span class="ident">T</span>) <span class="op">-&gt;</span> <span class="ident">Repeat</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span> {
    <span class="ident">Repeat</span>{<span class="ident">element</span>: <span class="ident">elt</span>}
}

<span class="doccomment">/// An iterator that repeats elements of type `A` endlessly by</span>
<span class="doccomment">/// applying the provided closure `F: FnMut() -&gt; A`.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This `struct` is created by the [`repeat_with`] function.</span>
<span class="doccomment">/// See its documentation for more.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// [`repeat_with`]: fn.repeat_with.html</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Copy</span>, <span class="ident">Clone</span>, <span class="ident">Debug</span>)]</span>
<span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">&quot;iterator_repeat_with&quot;</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">&quot;1.28.0&quot;</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">RepeatWith</span><span class="op">&lt;</span><span class="ident">F</span><span class="op">&gt;</span> {
    <span class="ident">repeater</span>: <span class="ident">F</span>
}

<span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">&quot;iterator_repeat_with&quot;</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">&quot;1.28.0&quot;</span>)]</span>
<span class="kw">impl</span><span class="op">&lt;</span><span class="ident">A</span>, <span class="ident">F</span>: <span class="ident">FnMut</span>() <span class="op">-&gt;</span> <span class="ident">A</span><span class="op">&gt;</span> <span class="ident">Iterator</span> <span class="kw">for</span> <span class="ident">RepeatWith</span><span class="op">&lt;</span><span class="ident">F</span><span class="op">&gt;</span> {
    <span class="kw">type</span> <span class="ident">Item</span> <span class="op">=</span> <span class="ident">A</span>;

    <span class="attribute">#[<span class="ident">inline</span>]</span>
    <span class="kw">fn</span> <span class="ident">next</span>(<span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-&gt;</span> <span class="prelude-ty">Option</span><span class="op">&lt;</span><span class="ident">A</span><span class="op">&gt;</span> { <span class="prelude-val">Some</span>((<span class="self">self</span>.<span class="ident">repeater</span>)()) }

    <span class="attribute">#[<span class="ident">inline</span>]</span>
    <span class="kw">fn</span> <span class="ident">size_hint</span>(<span class="kw-2">&amp;</span><span class="self">self</span>) <span class="op">-&gt;</span> (<span class="ident">usize</span>, <span class="prelude-ty">Option</span><span class="op">&lt;</span><span class="ident">usize</span><span class="op">&gt;</span>) { (<span class="ident">usize</span>::<span class="ident">MAX</span>, <span class="prelude-val">None</span>) }
}

<span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">&quot;iterator_repeat_with&quot;</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">&quot;1.28.0&quot;</span>)]</span>
<span class="kw">impl</span><span class="op">&lt;</span><span class="ident">A</span>, <span class="ident">F</span>: <span class="ident">FnMut</span>() <span class="op">-&gt;</span> <span class="ident">A</span><span class="op">&gt;</span> <span class="ident">FusedIterator</span> <span class="kw">for</span> <span class="ident">RepeatWith</span><span class="op">&lt;</span><span class="ident">F</span><span class="op">&gt;</span> {}

<span class="attribute">#[<span class="ident">unstable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">&quot;trusted_len&quot;</span>, <span class="ident">issue</span> <span class="op">=</span> <span class="string">&quot;37572&quot;</span>)]</span>
<span class="kw">unsafe</span> <span class="kw">impl</span><span class="op">&lt;</span><span class="ident">A</span>, <span class="ident">F</span>: <span class="ident">FnMut</span>() <span class="op">-&gt;</span> <span class="ident">A</span><span class="op">&gt;</span> <span class="ident">TrustedLen</span> <span class="kw">for</span> <span class="ident">RepeatWith</span><span class="op">&lt;</span><span class="ident">F</span><span class="op">&gt;</span> {}

<span class="doccomment">/// Creates a new iterator that repeats elements of type `A` endlessly by</span>
<span class="doccomment">/// applying the provided closure, the repeater, `F: FnMut() -&gt; A`.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The `repeat_with()` function calls the repeater over and over and over and</span>
<span class="doccomment">/// over and over and 🔁.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Infinite iterators like `repeat_with()` are often used with adapters like</span>
<span class="doccomment">/// [`take`], in order to make them finite.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// [`take`]: trait.Iterator.html#method.take</span>
<span class="doccomment">///</span>
<span class="doccomment">/// If the element type of the iterator you need implements `Clone`, and</span>
<span class="doccomment">/// it is OK to keep the source element in memory, you should instead use</span>
<span class="doccomment">/// the [`repeat`] function.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// [`repeat`]: fn.repeat.html</span>
<span class="doccomment">///</span>
<span class="doccomment">/// An iterator produced by `repeat_with()` is not a `DoubleEndedIterator`.</span>
<span class="doccomment">/// If you need `repeat_with()` to return a `DoubleEndedIterator`,</span>
<span class="doccomment">/// please open a GitHub issue explaining your use case.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Basic usage:</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use std::iter;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// // let&#39;s assume we have some value of a type that is not `Clone`</span>
<span class="doccomment">/// // or which don&#39;t want to have in memory just yet because it is expensive:</span>
<span class="doccomment">/// #[derive(PartialEq, Debug)]</span>
<span class="doccomment">/// struct Expensive;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// // a particular value forever:</span>
<span class="doccomment">/// let mut things = iter::repeat_with(|| Expensive);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(Some(Expensive), things.next());</span>
<span class="doccomment">/// assert_eq!(Some(Expensive), things.next());</span>
<span class="doccomment">/// assert_eq!(Some(Expensive), things.next());</span>
<span class="doccomment">/// assert_eq!(Some(Expensive), things.next());</span>
<span class="doccomment">/// assert_eq!(Some(Expensive), things.next());</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Using mutation and going finite:</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```rust</span>
<span class="doccomment">/// use std::iter;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// // From the zeroth to the third power of two:</span>
<span class="doccomment">/// let mut curr = 1;</span>
<span class="doccomment">/// let mut pow2 = iter::repeat_with(|| { let tmp = curr; curr *= 2; tmp })</span>
<span class="doccomment">///                     .take(4);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(Some(1), pow2.next());</span>
<span class="doccomment">/// assert_eq!(Some(2), pow2.next());</span>
<span class="doccomment">/// assert_eq!(Some(4), pow2.next());</span>
<span class="doccomment">/// assert_eq!(Some(8), pow2.next());</span>
<span class="doccomment">///</span>
<span class="doccomment">/// // ... and now we&#39;re done</span>
<span class="doccomment">/// assert_eq!(None, pow2.next());</span>
<span class="doccomment">/// ```</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">&quot;iterator_repeat_with&quot;</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">&quot;1.28.0&quot;</span>)]</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">repeat_with</span><span class="op">&lt;</span><span class="ident">A</span>, <span class="ident">F</span>: <span class="ident">FnMut</span>() <span class="op">-&gt;</span> <span class="ident">A</span><span class="op">&gt;</span>(<span class="ident">repeater</span>: <span class="ident">F</span>) <span class="op">-&gt;</span> <span class="ident">RepeatWith</span><span class="op">&lt;</span><span class="ident">F</span><span class="op">&gt;</span> {
    <span class="ident">RepeatWith</span> { <span class="ident">repeater</span> }
}

<span class="doccomment">/// An iterator that yields nothing.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This `struct` is created by the [`empty`] function. See its documentation for more.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// [`empty`]: fn.empty.html</span>
<span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">&quot;iter_empty&quot;</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">&quot;1.2.0&quot;</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Empty</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span>(<span class="ident">marker</span>::<span class="ident">PhantomData</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span>);

<span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">&quot;core_impl_debug&quot;</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">&quot;1.9.0&quot;</span>)]</span>
<span class="kw">impl</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span> <span class="ident">fmt</span>::<span class="ident">Debug</span> <span class="kw">for</span> <span class="ident">Empty</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span> {
    <span class="kw">fn</span> <span class="ident">fmt</span>(<span class="kw-2">&amp;</span><span class="self">self</span>, <span class="ident">f</span>: <span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="ident">fmt</span>::<span class="ident">Formatter</span>) <span class="op">-&gt;</span> <span class="ident">fmt</span>::<span class="prelude-ty">Result</span> {
        <span class="ident">f</span>.<span class="ident">pad</span>(<span class="string">&quot;Empty&quot;</span>)
    }
}

<span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">&quot;iter_empty&quot;</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">&quot;1.2.0&quot;</span>)]</span>
<span class="kw">impl</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span> <span class="ident">Iterator</span> <span class="kw">for</span> <span class="ident">Empty</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span> {
    <span class="kw">type</span> <span class="ident">Item</span> <span class="op">=</span> <span class="ident">T</span>;

    <span class="kw">fn</span> <span class="ident">next</span>(<span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-&gt;</span> <span class="prelude-ty">Option</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span> {
        <span class="prelude-val">None</span>
    }

    <span class="kw">fn</span> <span class="ident">size_hint</span>(<span class="kw-2">&amp;</span><span class="self">self</span>) <span class="op">-&gt;</span> (<span class="ident">usize</span>, <span class="prelude-ty">Option</span><span class="op">&lt;</span><span class="ident">usize</span><span class="op">&gt;</span>){
        (<span class="number">0</span>, <span class="prelude-val">Some</span>(<span class="number">0</span>))
    }
}

<span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">&quot;iter_empty&quot;</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">&quot;1.2.0&quot;</span>)]</span>
<span class="kw">impl</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span> <span class="ident">DoubleEndedIterator</span> <span class="kw">for</span> <span class="ident">Empty</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span> {
    <span class="kw">fn</span> <span class="ident">next_back</span>(<span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-&gt;</span> <span class="prelude-ty">Option</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span> {
        <span class="prelude-val">None</span>
    }
}

<span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">&quot;iter_empty&quot;</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">&quot;1.2.0&quot;</span>)]</span>
<span class="kw">impl</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span> <span class="ident">ExactSizeIterator</span> <span class="kw">for</span> <span class="ident">Empty</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span> {
    <span class="kw">fn</span> <span class="ident">len</span>(<span class="kw-2">&amp;</span><span class="self">self</span>) <span class="op">-&gt;</span> <span class="ident">usize</span> {
        <span class="number">0</span>
    }
}

<span class="attribute">#[<span class="ident">unstable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">&quot;trusted_len&quot;</span>, <span class="ident">issue</span> <span class="op">=</span> <span class="string">&quot;37572&quot;</span>)]</span>
<span class="kw">unsafe</span> <span class="kw">impl</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span> <span class="ident">TrustedLen</span> <span class="kw">for</span> <span class="ident">Empty</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span> {}

<span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">&quot;fused&quot;</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">&quot;1.26.0&quot;</span>)]</span>
<span class="kw">impl</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span> <span class="ident">FusedIterator</span> <span class="kw">for</span> <span class="ident">Empty</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span> {}

<span class="comment">// not #[derive] because that adds a Clone bound on T,</span>
<span class="comment">// which isn&#39;t necessary.</span>
<span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">&quot;iter_empty&quot;</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">&quot;1.2.0&quot;</span>)]</span>
<span class="kw">impl</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span> <span class="ident">Clone</span> <span class="kw">for</span> <span class="ident">Empty</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span> {
    <span class="kw">fn</span> <span class="ident">clone</span>(<span class="kw-2">&amp;</span><span class="self">self</span>) <span class="op">-&gt;</span> <span class="ident">Empty</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span> {
        <span class="ident">Empty</span>(<span class="ident">marker</span>::<span class="ident">PhantomData</span>)
    }
}

<span class="comment">// not #[derive] because that adds a Default bound on T,</span>
<span class="comment">// which isn&#39;t necessary.</span>
<span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">&quot;iter_empty&quot;</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">&quot;1.2.0&quot;</span>)]</span>
<span class="kw">impl</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span> <span class="ident">Default</span> <span class="kw">for</span> <span class="ident">Empty</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span> {
    <span class="kw">fn</span> <span class="ident">default</span>() <span class="op">-&gt;</span> <span class="ident">Empty</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span> {
        <span class="ident">Empty</span>(<span class="ident">marker</span>::<span class="ident">PhantomData</span>)
    }
}

<span class="doccomment">/// Creates an iterator that yields nothing.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Basic usage:</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use std::iter;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// // this could have been an iterator over i32, but alas, it&#39;s just not.</span>
<span class="doccomment">/// let mut nope = iter::empty::&lt;i32&gt;();</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(None, nope.next());</span>
<span class="doccomment">/// ```</span>
<span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">&quot;iter_empty&quot;</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">&quot;1.2.0&quot;</span>)]</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">empty</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span>() <span class="op">-&gt;</span> <span class="ident">Empty</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span> {
    <span class="ident">Empty</span>(<span class="ident">marker</span>::<span class="ident">PhantomData</span>)
}

<span class="doccomment">/// An iterator that yields an element exactly once.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This `struct` is created by the [`once`] function. See its documentation for more.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// [`once`]: fn.once.html</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>)]</span>
<span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">&quot;iter_once&quot;</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">&quot;1.2.0&quot;</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Once</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span> {
    <span class="ident">inner</span>: ::<span class="ident">option</span>::<span class="ident">IntoIter</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span>
}

<span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">&quot;iter_once&quot;</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">&quot;1.2.0&quot;</span>)]</span>
<span class="kw">impl</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span> <span class="ident">Iterator</span> <span class="kw">for</span> <span class="ident">Once</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span> {
    <span class="kw">type</span> <span class="ident">Item</span> <span class="op">=</span> <span class="ident">T</span>;

    <span class="kw">fn</span> <span class="ident">next</span>(<span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-&gt;</span> <span class="prelude-ty">Option</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span> {
        <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">next</span>()
    }

    <span class="kw">fn</span> <span class="ident">size_hint</span>(<span class="kw-2">&amp;</span><span class="self">self</span>) <span class="op">-&gt;</span> (<span class="ident">usize</span>, <span class="prelude-ty">Option</span><span class="op">&lt;</span><span class="ident">usize</span><span class="op">&gt;</span>) {
        <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">size_hint</span>()
    }
}

<span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">&quot;iter_once&quot;</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">&quot;1.2.0&quot;</span>)]</span>
<span class="kw">impl</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span> <span class="ident">DoubleEndedIterator</span> <span class="kw">for</span> <span class="ident">Once</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span> {
    <span class="kw">fn</span> <span class="ident">next_back</span>(<span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-&gt;</span> <span class="prelude-ty">Option</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span> {
        <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">next_back</span>()
    }
}

<span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">&quot;iter_once&quot;</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">&quot;1.2.0&quot;</span>)]</span>
<span class="kw">impl</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span> <span class="ident">ExactSizeIterator</span> <span class="kw">for</span> <span class="ident">Once</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span> {
    <span class="kw">fn</span> <span class="ident">len</span>(<span class="kw-2">&amp;</span><span class="self">self</span>) <span class="op">-&gt;</span> <span class="ident">usize</span> {
        <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">len</span>()
    }
}

<span class="attribute">#[<span class="ident">unstable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">&quot;trusted_len&quot;</span>, <span class="ident">issue</span> <span class="op">=</span> <span class="string">&quot;37572&quot;</span>)]</span>
<span class="kw">unsafe</span> <span class="kw">impl</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span> <span class="ident">TrustedLen</span> <span class="kw">for</span> <span class="ident">Once</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span> {}

<span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">&quot;fused&quot;</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">&quot;1.26.0&quot;</span>)]</span>
<span class="kw">impl</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span> <span class="ident">FusedIterator</span> <span class="kw">for</span> <span class="ident">Once</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span> {}

<span class="doccomment">/// Creates an iterator that yields an element exactly once.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This is commonly used to adapt a single value into a [`chain`] of other</span>
<span class="doccomment">/// kinds of iteration. Maybe you have an iterator that covers almost</span>
<span class="doccomment">/// everything, but you need an extra special case. Maybe you have a function</span>
<span class="doccomment">/// which works on iterators, but you only need to process one value.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// [`chain`]: trait.Iterator.html#method.chain</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Basic usage:</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use std::iter;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// // one is the loneliest number</span>
<span class="doccomment">/// let mut one = iter::once(1);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(Some(1), one.next());</span>
<span class="doccomment">///</span>
<span class="doccomment">/// // just one, that&#39;s all we get</span>
<span class="doccomment">/// assert_eq!(None, one.next());</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Chaining together with another iterator. Let&#39;s say that we want to iterate</span>
<span class="doccomment">/// over each file of the `.foo` directory, but also a configuration file,</span>
<span class="doccomment">/// `.foorc`:</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```no_run</span>
<span class="doccomment">/// use std::iter;</span>
<span class="doccomment">/// use std::fs;</span>
<span class="doccomment">/// use std::path::PathBuf;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let dirs = fs::read_dir(&quot;.foo&quot;).unwrap();</span>
<span class="doccomment">///</span>
<span class="doccomment">/// // we need to convert from an iterator of DirEntry-s to an iterator of</span>
<span class="doccomment">/// // PathBufs, so we use map</span>
<span class="doccomment">/// let dirs = dirs.map(|file| file.unwrap().path());</span>
<span class="doccomment">///</span>
<span class="doccomment">/// // now, our iterator just for our config file</span>
<span class="doccomment">/// let config = iter::once(PathBuf::from(&quot;.foorc&quot;));</span>
<span class="doccomment">///</span>
<span class="doccomment">/// // chain the two iterators together into one big iterator</span>
<span class="doccomment">/// let files = dirs.chain(config);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// // this will give us all of the files in .foo as well as .foorc</span>
<span class="doccomment">/// for f in files {</span>
<span class="doccomment">///     println!(&quot;{:?}&quot;, f);</span>
<span class="doccomment">/// }</span>
<span class="doccomment">/// ```</span>
<span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">&quot;iter_once&quot;</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">&quot;1.2.0&quot;</span>)]</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">once</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span>(<span class="ident">value</span>: <span class="ident">T</span>) <span class="op">-&gt;</span> <span class="ident">Once</span><span class="op">&lt;</span><span class="ident">T</span><span class="op">&gt;</span> {
    <span class="ident">Once</span> { <span class="ident">inner</span>: <span class="prelude-val">Some</span>(<span class="ident">value</span>).<span class="ident">into_iter</span>() }
}
</pre>
</section><section id="search" class="content hidden"></section><section class="footer"></section><aside id="help" class="hidden"><div><h1 class="hidden">Help</h1><div class="shortcuts"><h2>Keyboard Shortcuts</h2><dl><dt><kbd>?</kbd></dt><dd>Show this help dialog</dd><dt><kbd>S</kbd></dt><dd>Focus the search field</dd><dt><kbd>↑</kbd></dt><dd>Move up in search results</dd><dt><kbd>↓</kbd></dt><dd>Move down in search results</dd><dt><kbd>↹</kbd></dt><dd>Switch tab</dd><dt><kbd>&#9166;</kbd></dt><dd>Go to active search result</dd><dt><kbd>+</kbd></dt><dd>Expand all sections</dd><dt><kbd>-</kbd></dt><dd>Collapse all sections</dd></dl></div><div class="infos"><h2>Search Tricks</h2><p>Prefix searches with a type followed by a colon (e.g. <code>fn:</code>) to restrict the search to a given type.</p><p>Accepted types are: <code>fn</code>, <code>mod</code>, <code>struct</code>, <code>enum</code>, <code>trait</code>, <code>type</code>, <code>macro</code>, and <code>const</code>.</p><p>Search functions by type signature (e.g. <code>vec -> usize</code> or <code>* -> vec</code>)</p><p>Search multiple things at once by splitting your query with comma (e.g. <code>str,u8</code> or <code>String,struct:Vec,test</code>)</p></div></div></aside><script>window.rootPath = "../../../";window.currentCrate = "core";</script><script src="../../../aliases.js"></script><script src="../../../main.js"></script><script defer src="../../../search-index.js"></script></body></html>