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  <meta name="dcterms.date" content="2021-09-17" />
  <title>views::move</title>
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<h1 class="title" style="text-align:center"><code class="sourceCode cpp">views<span class="op">::</span>move</code></h1>

<table style="border:none;float:right">
  <tr>
    <td>Document #:</td>
    <td>P2446R0</td>
  </tr>
  <tr>
    <td>Date:</td>
    <td>2021-09-17</td>
  </tr>
  <tr>
    <td style="vertical-align:top">Project:</td>
    <td>Programming Language C++</td>
  </tr>
  <tr>
    <td style="vertical-align:top">Audience:</td>
    <td>
      LEWG<br>
    </td>
  </tr>
  <tr>
    <td style="vertical-align:top">Reply-to:</td>
    <td>
      Barry Revzin<br>&lt;<a href="mailto:barry.revzin@gmail.com" class="email">barry.revzin@gmail.com</a>&gt;<br>
    </td>
  </tr>
</table>

</header>
<div style="clear:both">
<div id="TOC" role="doc-toc">
<h1 id="toctitle">Contents</h1>
<ul>
<li><a href="#introduction"><span class="toc-section-number">1</span> Introduction<span></span></a>
<ul>
<li><a href="#but-why-now"><span class="toc-section-number">1.1</span> But why now?<span></span></a></li>
</ul></li>
<li><a href="#wording"><span class="toc-section-number">2</span> Wording<span></span></a>
<ul>
<li><a href="#move-view-range.move">24.7.? Move view [range.move]<span></span></a></li>
</ul></li>
<li><a href="#bibliography"><span class="toc-section-number">3</span> References<span></span></a></li>
</ul>
</div>
<h1 data-number="1" style="border-bottom:1px solid #cccccc" id="introduction"><span class="header-section-number">1</span> Introduction<a href="#introduction" class="self-link"></a></h1>
<p>In <span class="citation" data-cites="P2214R1">[<a href="#ref-P2214R1" role="doc-biblioref">P2214R1</a>]</span>, I wrote:</p>
<div class="quote">
<p>Several of the above views that are labeled “not proposed” are variations on a common theme: <code class="sourceCode cpp">addressof</code>, <code class="sourceCode cpp">indirect</code>, and <code class="sourceCode cpp">move</code> are all basically wrappers around <code class="sourceCode cpp">transform</code> that take <code class="sourceCode cpp">std<span class="op">::</span>addressof</code>, <code class="sourceCode cpp">std<span class="op">::</span>dereference</code> (a function object we do not have at the moment), and <code class="sourceCode cpp">std<span class="op">::</span>move</code>, respectively. Basically, but not exactly, since one of those functions doesn’t exist yet and the other three we can’t pass as an argument anyway.</p>
<p>But some sort of broader ability to pass functions into functions would mostly alleviate the need for these. <code class="sourceCode cpp">views<span class="op">::</span>addressof</code> is shorter than <code class="sourceCode cpp">views<span class="op">::</span>transform<span class="op">(</span>LIFT<span class="op">(</span>std<span class="op">::</span>addressof<span class="op">))</span></code> (assuming a LIFT macro that wraps a name and emits a lambda), but we’re not sure that we necessarily need to add special cases of transform for every useful function.</p>
</div>
<p>While this is true for <code class="sourceCode cpp">views<span class="op">::</span>addressof</code> and <code class="sourceCode cpp">views<span class="op">::</span>indirect</code>, it’s actually <em>not</em> correct for <code class="sourceCode cpp">views<span class="op">::</span>move</code>. There is actually a lot more involvement here.</p>
<p>To start with, while if we had a range of lvalues, we would just want to <code class="sourceCode cpp">std<span class="op">::</span>move<span class="op">()</span></code> each element of the range, that’s not true if we had a range of rvalues. Those… we wouldn’t really have to do anything with (indeed, if we had a range of prvalues, the extra <code class="sourceCode cpp">std<span class="op">::</span>move<span class="op">()</span></code> would just add unnecessary overhead by materializing those objects earlier). Except in some cases, we <em>do</em> still want to do something with the prvalues - if we were <code class="sourceCode cpp">zip<span class="op">()</span></code>ing <span class="citation" data-cites="P2321R2">[<a href="#ref-P2321R2" role="doc-biblioref">P2321R2</a>]</span> one range of lvalues, we would get back a range of <code class="sourceCode cpp">tuple<span class="op">&lt;</span>T<span class="op">&amp;&gt;</span></code>. But the result of piping that into <code class="sourceCode cpp">views<span class="op">::</span>move</code> shouldn’t be <code class="sourceCode cpp">tuple<span class="op">&lt;</span>T<span class="op">&amp;&gt;&amp;&amp;</span></code> (as a naive <code class="sourceCode cpp">views<span class="op">::</span>transform<span class="op">(</span>std<span class="op">::</span>move<span class="op">)</span></code> would do) and it shouldn’t be <code class="sourceCode cpp">tuple<span class="op">&lt;</span>T<span class="op">&amp;&gt;</span></code> (as a slightly less naive implementation that avoids transforming rvalues) - we should get back a range of <code class="sourceCode cpp">tuple<span class="op">&lt;</span>T<span class="op">&amp;&amp;&gt;</span></code>.</p>
<p>Indeed, we already have a customization point that does this for us: <code class="sourceCode cpp">ranges<span class="op">::</span>iter_move</code> <span>23.3.3.1 <a href="https://wg21.link/iterator.cust.move">[iterator.cust.move]</a></span>. But we can’t pass that into <code class="sourceCode cpp">views<span class="op">::</span>transform</code>, because <code class="sourceCode cpp">ranges<span class="op">::</span>iter_move</code> operators on the iterator (as the name suggest) and not the underlying element. We would need to spell this as <code class="sourceCode cpp">views<span class="op">::</span>iter_transform<span class="op">(</span>ranges<span class="op">::</span>iter_move<span class="op">)</span></code>, but we don’t yet have a <code class="sourceCode cpp">views<span class="op">::</span>iter_transform</code> (although range-v3 does).</p>
<p>However, even if we could define <code class="sourceCode cpp">views<span class="op">::</span>move</code> as simply <code class="sourceCode cpp">views<span class="op">::</span>iter_transform<span class="op">(</span>ranges<span class="op">::</span>iter_move<span class="op">)</span></code>, that’s still a poor definition, for a very important reason: <code class="sourceCode cpp">ranges<span class="op">::</span>iter_move</code> (just like <code class="sourceCode cpp">std<span class="op">::</span>move</code>) isn’t just <em>some</em> arbitrary transformation. We know a lot about this particular one, and specifically we know that it consumes the source element. And as a result, that <em>should</em> limit the algorithms that you can perform on <code class="sourceCode cpp">views<span class="op">::</span>move<span class="op">(</span>e<span class="op">)</span></code> - such an adapted range needs to be an <em>input</em> range. <code class="sourceCode cpp">views<span class="op">::</span>transform<span class="op">(</span>e, std<span class="op">::</span>move<span class="op">)</span></code> and <code class="sourceCode cpp">views<span class="op">::</span>iter_transform<span class="op">(</span>e, ranges<span class="op">::</span>iter_move<span class="op">)</span></code> would both be potentially up to random-access, but we need to set a much much lower ceiling here.</p>
<p>As such, <code class="sourceCode cpp">views<span class="op">::</span>move</code> needs to be a first-class range adaptor.</p>
<h2 data-number="1.1" id="but-why-now"><span class="header-section-number">1.1</span> But why now?<a href="#but-why-now" class="self-link"></a></h2>
<p>The above argues why <code class="sourceCode cpp">views<span class="op">::</span>move</code> can’t just be a <code class="sourceCode cpp">views<span class="op">::</span>transform</code> or a <code class="sourceCode cpp">views<span class="op">::</span>iter_transform</code>, but why do we need it now? Well, there are two answers to this.</p>
<p>First, with the imminent adoption of <code class="sourceCode cpp">ranges<span class="op">::</span>to</code> <span class="citation" data-cites="P1206R6">[<a href="#ref-P1206R6" role="doc-biblioref">P1206R6</a>]</span>, we spent a lot of time on that paper trying to make collecting of elements as efficient as possible. As efficient as possible certainly includes <em>moving</em> elements instead of <em>copying</em> elements, where appropriate. However, right now, it’s really up to users to figure out how to do that. A <code class="sourceCode cpp">views<span class="op">::</span>move</code> would go a long way in making this as effortless as possible (and mirrors how users would move a single element).</p>
<p>Second, unlike <code class="sourceCode cpp">views<span class="op">::</span>as_const</code> <span class="citation" data-cites="P2278R1">[<a href="#ref-P2278R1" role="doc-biblioref">P2278R1</a>]</span>, where a lot of design effort had to be spent figuring out how to implement a constant iterator, that work has already been done for move iterators. <code class="sourceCode cpp">std<span class="op">::</span>move_iterator<span class="op">&lt;</span>I<span class="op">&gt;</span></code> <span>23.5.3 <a href="https://wg21.link/move.iterators">[move.iterators]</a></span> exists and already does the right thing, and there’s already a <code class="sourceCode cpp">std<span class="op">::</span>move_sentinel<span class="op">&lt;</span>S<span class="op">&gt;</span></code> <span>23.5.3.10 <a href="https://wg21.link/move.sentinel">[move.sentinel]</a></span> to handle non-common ranges. All the work is done, we just have to put it together. As you can see below, the wording is pretty small and very straightforward.</p>
<p>This is a tiny paper, and while this should be considered the lowest priority of all the range adaptors (as the C++23 Ranges Plan doesn’t even propose it at all), we may as well at least try to squeeze it in.</p>
<h1 data-number="2" style="border-bottom:1px solid #cccccc" id="wording"><span class="header-section-number">2</span> Wording<a href="#wording" class="self-link"></a></h1>
<p>Add to <span>24.2 <a href="https://wg21.link/ranges.syn">[ranges.syn]</a></span>:</p>
<blockquote>
<div>
<div class="sourceCode" id="cb1"><pre class="sourceCode diff"><code class="sourceCode diff"><span id="cb1-1"><a href="#cb1-1"></a>#include &lt;compare&gt;              // see [compare.syn]</span>
<span id="cb1-2"><a href="#cb1-2"></a>#include &lt;initializer_list&gt;     // see [initializer.list.syn]</span>
<span id="cb1-3"><a href="#cb1-3"></a>#include &lt;iterator&gt;             // see [iterator.synopsis]</span>
<span id="cb1-4"><a href="#cb1-4"></a></span>
<span id="cb1-5"><a href="#cb1-5"></a>namespace std::ranges {</span>
<span id="cb1-6"><a href="#cb1-6"></a>  // ...</span>
<span id="cb1-7"><a href="#cb1-7"></a><span class="va">+</span></span>
<span id="cb1-8"><a href="#cb1-8"></a><span class="va">+ template&lt;view V&gt;  </span></span>
<span id="cb1-9"><a href="#cb1-9"></a><span class="va">+   requires input_range&lt;V&gt;</span></span>
<span id="cb1-10"><a href="#cb1-10"></a><span class="va">+ class move_view;</span></span>
<span id="cb1-11"><a href="#cb1-11"></a><span class="va">+ </span></span>
<span id="cb1-12"><a href="#cb1-12"></a><span class="va">+ template&lt;class T&gt;</span></span>
<span id="cb1-13"><a href="#cb1-13"></a><span class="va">+   inline constexpr bool enable_borrowed_range&lt;move_view&lt;T&gt;&gt; = enable_borrowed_range&lt;T&gt;;</span></span>
<span id="cb1-14"><a href="#cb1-14"></a><span class="va">+ </span></span>
<span id="cb1-15"><a href="#cb1-15"></a><span class="va">+ namespace views { inline constexpr <em>unspecified</em> move = <em>unspecified</em>; }</span></span>
<span id="cb1-16"><a href="#cb1-16"></a>  </span>
<span id="cb1-17"><a href="#cb1-17"></a>  // ...</span>
<span id="cb1-18"><a href="#cb1-18"></a>}</span></code></pre></div>
</div>
</blockquote>
<h3 class="unnumbered" data-number id="move-view-range.move">24.7.? Move view [range.move]<a href="#move-view-range.move" class="self-link"></a></h3>
<h4 class="unnumbered" data-number id="overview-range.move.overview">24.7.?.1 Overview [range.move.overview]<a href="#overview-range.move.overview" class="self-link"></a></h4>
<blockquote>
<p><span class="marginalizedparent"><a class="marginalized" href="#pnum_1" id="pnum_1">1</a></span> <code class="sourceCode cpp">move_view</code> presents a <code class="sourceCode cpp">view</code> of an underlying sequence with the same behavior as the underlying sequence except that its elements are rvalues. Some generic algorithms can be called with a <code class="sourceCode cpp">move_view</code> to replace copying with moving.</p>
<p><span class="marginalizedparent"><a class="marginalized" href="#pnum_2" id="pnum_2">2</a></span> The name <code class="sourceCode cpp">views<span class="op">::</span>move</code> denotes a range adaptor object ([range.adaptor.object]). Let <code class="sourceCode cpp">E</code> be an expression and let <code class="sourceCode cpp">T</code> be <code class="sourceCode cpp"><span class="kw">decltype</span><span class="op">((</span>E<span class="op">))</span></code>. The expression <code class="sourceCode cpp">views<span class="op">::</span>move<span class="op">(</span>E<span class="op">)</span></code> is expression-equivalent to:</p>
<ul>
<li><span class="marginalizedparent"><a class="marginalized" href="#pnum_3" id="pnum_3">(2.1)</a></span> <code class="sourceCode cpp">views<span class="op">::</span>all<span class="op">(</span>E<span class="op">)</span></code> if <code class="sourceCode cpp">same_as<span class="op">&lt;</span>range_rvalue_reference_t<span class="op">&lt;</span>T<span class="op">&gt;</span>, range_reference_t<span class="op">&lt;</span>T<span class="op">&gt;&gt;</span></code> is <code class="sourceCode cpp"><span class="kw">true</span></code></li>
<li><span class="marginalizedparent"><a class="marginalized" href="#pnum_4" id="pnum_4">(2.2)</a></span> Otherwise, <code class="sourceCode cpp">ranges<span class="op">::</span>move_view<span class="op">{</span>E<span class="op">}</span></code>.</li>
</ul>
<p><span class="marginalizedparent"><a class="marginalized" href="#pnum_5" id="pnum_5">3</a></span> [<em>Example</em>:</p>
<div class="sourceCode" id="cb2"><pre class="sourceCode cpp"><code class="sourceCode cpp"><span id="cb2-1"><a href="#cb2-1"></a>std<span class="op">::</span>vector<span class="op">&lt;</span>string<span class="op">&gt;</span> words <span class="op">=</span> <span class="op">{</span><span class="st">&quot;the&quot;</span>, <span class="st">&quot;quick&quot;</span>, <span class="st">&quot;brown&quot;</span>, <span class="st">&quot;fox&quot;</span>, <span class="st">&quot;ate&quot;</span>, <span class="st">&quot;a&quot;</span>, <span class="st">&quot;pterodactyl&quot;</span><span class="op">}</span>;</span>
<span id="cb2-2"><a href="#cb2-2"></a>std<span class="op">::</span>vector<span class="op">&lt;</span>string<span class="op">&gt;</span> new_words;</span>
<span id="cb2-3"><a href="#cb2-3"></a>std<span class="op">::</span>ranges<span class="op">::</span>copy<span class="op">(</span>words <span class="op">|</span> views<span class="op">::</span>move, std<span class="op">::</span>back_inserter<span class="op">(</span><span class="dt">long</span><span class="op">))</span>; <span class="co">// moves each string from words into new_words</span></span></code></pre></div>
<p>-<em>end example</em>]</p>
</blockquote>
<h4 class="unnumbered" data-number id="class-template-move_view-range.move.view">24.7.?.2 Class template <code class="sourceCode cpp">move_view</code> [range.move.view]<a href="#class-template-move_view-range.move.view" class="self-link"></a></h4>
<blockquote>
<div class="sourceCode" id="cb3"><pre class="sourceCode cpp"><code class="sourceCode cpp"><span id="cb3-1"><a href="#cb3-1"></a><span class="kw">namespace</span> std<span class="op">::</span>ranges <span class="op">{</span></span>
<span id="cb3-2"><a href="#cb3-2"></a>  <span class="kw">template</span><span class="op">&lt;</span>input_range V<span class="op">&gt;</span></span>
<span id="cb3-3"><a href="#cb3-3"></a>    <span class="kw">requires</span> view<span class="op">&lt;</span>V<span class="op">&gt;</span></span>
<span id="cb3-4"><a href="#cb3-4"></a>  <span class="kw">class</span> move_view <span class="op">:</span> <span class="kw">public</span> view_interface<span class="op">&lt;</span>move_view<span class="op">&lt;</span>V<span class="op">&gt;&gt;</span></span>
<span id="cb3-5"><a href="#cb3-5"></a>  <span class="op">{</span></span>
<span id="cb3-6"><a href="#cb3-6"></a>    V <em>base_</em> <span class="op">=</span> V<span class="op">()</span>; <span class="co">// exposition only</span></span>
<span id="cb3-7"><a href="#cb3-7"></a>    </span>
<span id="cb3-8"><a href="#cb3-8"></a>  <span class="kw">public</span><span class="op">:</span></span>
<span id="cb3-9"><a href="#cb3-9"></a>    move_view<span class="op">()</span> <span class="kw">requires</span> default_initializable<span class="op">&lt;</span>V<span class="op">&gt;</span> <span class="op">=</span> <span class="cf">default</span>;</span>
<span id="cb3-10"><a href="#cb3-10"></a>    <span class="kw">constexpr</span> <span class="kw">explicit</span> move_view<span class="op">(</span>V base<span class="op">)</span>;</span>
<span id="cb3-11"><a href="#cb3-11"></a>    </span>
<span id="cb3-12"><a href="#cb3-12"></a>    <span class="kw">constexpr</span> V base<span class="op">()</span> <span class="kw">const</span><span class="op">&amp;</span> <span class="kw">requires</span> copy_constructible<span class="op">&lt;</span>V<span class="op">&gt;</span> <span class="op">{</span> <span class="cf">return</span> <em>base_</em>; <span class="op">}</span></span>
<span id="cb3-13"><a href="#cb3-13"></a>    <span class="kw">constexpr</span> V base<span class="op">()</span> <span class="op">&amp;&amp;</span> <span class="op">{</span> <span class="cf">return</span> std<span class="op">::</span>move<span class="op">(</span><em>base_</em><span class="op">)</span>; <span class="op">}</span>    </span>
<span id="cb3-14"><a href="#cb3-14"></a>    </span>
<span id="cb3-15"><a href="#cb3-15"></a>    <span class="kw">constexpr</span> <span class="kw">auto</span> begin<span class="op">()</span> <span class="kw">requires</span> <span class="op">(!</span><em>simple-view</em><span class="op">&lt;</span>V<span class="op">&gt;)</span> <span class="op">{</span> <span class="cf">return</span> std<span class="op">::</span>move_iterator<span class="op">(</span>ranges<span class="op">::</span>begin<span class="op">(</span><em>base_</em><span class="op">))</span>; <span class="op">}</span></span>
<span id="cb3-16"><a href="#cb3-16"></a>    <span class="kw">constexpr</span> <span class="kw">auto</span> begin<span class="op">()</span> <span class="kw">const</span> <span class="kw">requires</span> range<span class="op">&lt;</span><span class="kw">const</span> V<span class="op">&gt;</span> <span class="op">{</span> <span class="cf">return</span> std<span class="op">::</span>move_iterator<span class="op">(</span>ranges<span class="op">::</span>begin<span class="op">(</span><em>base_</em><span class="op">))</span>; <span class="op">}</span></span>
<span id="cb3-17"><a href="#cb3-17"></a>    </span>
<span id="cb3-18"><a href="#cb3-18"></a>    <span class="kw">constexpr</span> <span class="kw">auto</span> end<span class="op">()</span> <span class="kw">requires</span> <span class="op">(!</span><em>simple-view</em><span class="op">&lt;</span>V<span class="op">&gt;)</span> <span class="op">{</span></span>
<span id="cb3-19"><a href="#cb3-19"></a>        <span class="cf">if</span> <span class="kw">constexpr</span> <span class="op">(</span>common_range<span class="op">&lt;</span>V<span class="op">&gt;)</span> <span class="op">{</span></span>
<span id="cb3-20"><a href="#cb3-20"></a>            <span class="cf">return</span> std<span class="op">::</span>move_iterator<span class="op">(</span>ranges<span class="op">::</span>end<span class="op">(</span><em>base_</em><span class="op">))</span>;</span>
<span id="cb3-21"><a href="#cb3-21"></a>        <span class="op">}</span> <span class="cf">else</span> <span class="op">{</span></span>
<span id="cb3-22"><a href="#cb3-22"></a>            <span class="cf">return</span> std<span class="op">::</span>move_sentinel<span class="op">(</span>ranges<span class="op">::</span>end<span class="op">(</span><em>base_</em><span class="op">))</span>;</span>
<span id="cb3-23"><a href="#cb3-23"></a>        <span class="op">}</span></span>
<span id="cb3-24"><a href="#cb3-24"></a>    <span class="op">}</span></span>
<span id="cb3-25"><a href="#cb3-25"></a>    <span class="kw">constexpr</span> <span class="kw">auto</span> end<span class="op">()</span> <span class="kw">const</span> <span class="kw">requires</span> range<span class="op">&lt;</span><span class="kw">const</span> V<span class="op">&gt;</span> <span class="op">{</span></span>
<span id="cb3-26"><a href="#cb3-26"></a>        <span class="cf">if</span> <span class="kw">constexpr</span> <span class="op">(</span>common_range<span class="op">&lt;</span><span class="kw">const</span> V<span class="op">&gt;)</span> <span class="op">{</span></span>
<span id="cb3-27"><a href="#cb3-27"></a>            <span class="cf">return</span> std<span class="op">::</span>move_iterator<span class="op">(</span>ranges<span class="op">::</span>end<span class="op">(</span><em>base_</em><span class="op">))</span>;</span>
<span id="cb3-28"><a href="#cb3-28"></a>        <span class="op">}</span> <span class="cf">else</span> <span class="op">{</span></span>
<span id="cb3-29"><a href="#cb3-29"></a>            <span class="cf">return</span> std<span class="op">::</span>move_sentinel<span class="op">(</span>ranges<span class="op">::</span>end<span class="op">(</span><em>base_</em><span class="op">))</span>;</span>
<span id="cb3-30"><a href="#cb3-30"></a>        <span class="op">}</span></span>
<span id="cb3-31"><a href="#cb3-31"></a>    <span class="op">}</span>    </span>
<span id="cb3-32"><a href="#cb3-32"></a>    </span>
<span id="cb3-33"><a href="#cb3-33"></a>    <span class="kw">constexpr</span> <span class="kw">auto</span> size<span class="op">()</span> <span class="kw">requires</span> sized_range<span class="op">&lt;</span>V<span class="op">&gt;</span> <span class="op">{</span> <span class="cf">return</span> ranges<span class="op">::</span>size<span class="op">(</span><em>base_</em><span class="op">)</span>; <span class="op">}</span></span>
<span id="cb3-34"><a href="#cb3-34"></a>    <span class="kw">constexpr</span> <span class="kw">auto</span> size<span class="op">()</span> <span class="kw">const</span> <span class="kw">requires</span> sized_range<span class="op">&lt;</span><span class="kw">const</span> V<span class="op">&gt;</span> <span class="op">{</span> <span class="cf">return</span> ranges<span class="op">::</span>size<span class="op">(</span><em>base_</em><span class="op">)</span>; <span class="op">}</span></span>
<span id="cb3-35"><a href="#cb3-35"></a>  <span class="op">}</span>;</span>
<span id="cb3-36"><a href="#cb3-36"></a>  </span>
<span id="cb3-37"><a href="#cb3-37"></a>  <span class="kw">template</span><span class="op">&lt;</span><span class="kw">class</span> R<span class="op">&gt;</span></span>
<span id="cb3-38"><a href="#cb3-38"></a>    move_view<span class="op">(</span>R<span class="op">&amp;&amp;)</span> <span class="op">-&gt;</span> move_view<span class="op">&lt;</span>views<span class="op">::</span>all_t<span class="op">&lt;</span>R<span class="op">&gt;&gt;</span>;</span>
<span id="cb3-39"><a href="#cb3-39"></a><span class="op">}</span></span></code></pre></div>
<div class="sourceCode" id="cb4"><pre class="sourceCode cpp"><code class="sourceCode cpp"><span id="cb4-1"><a href="#cb4-1"></a><span class="kw">constexpr</span> <span class="kw">explicit</span> move_view<span class="op">(</span>V base<span class="op">)</span>;</span></code></pre></div>
<p><span class="marginalizedparent"><a class="marginalized" href="#pnum_6" id="pnum_6">1</a></span> <em>Effects</em>: Initializes <code class="sourceCode cpp"><em>base_</em></code> with <code class="sourceCode cpp">std<span class="op">::</span>move<span class="op">(</span>base<span class="op">)</span></code>.</p>
</blockquote>
<h1 data-number="3" style="border-bottom:1px solid #cccccc" id="bibliography"><span class="header-section-number">3</span> References<a href="#bibliography" class="self-link"></a></h1>
<div id="refs" class="references hanging-indent" role="doc-bibliography">
<div id="ref-P1206R6">
<p>[P1206R6] Corentin Jabot, Eric Niebler, Casey Carter. 2021-08-03. Conversions from ranges to containers. <br />
<a href="https://wg21.link/p1206r6">https://wg21.link/p1206r6</a></p>
</div>
<div id="ref-P2214R1">
<p>[P2214R1] Barry Revzin, Conor Hoekstra, and Tim Song. 2021. A Plan for C++23 Ranges. <br />
<a href="https://wg21.link/p2214r1">https://wg21.link/p2214r1</a></p>
</div>
<div id="ref-P2278R1">
<p>[P2278R1] Barry Revzin. 2021. <code class="sourceCode cpp">cbegin</code> should always return a constant iterator. <br />
<a href="https://wg21.link/p2278r1">https://wg21.link/p2278r1</a></p>
</div>
<div id="ref-P2321R2">
<p>[P2321R2] Tim Song. 2021-06-11. zip. <br />
<a href="https://wg21.link/p2321r2">https://wg21.link/p2321r2</a></p>
</div>
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