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<title>Issue 4054: Repeating a repeat_view should repeat the view</title>
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<p><em>This page is a snapshot from the LWG issues list, see the <a href="lwg-active.html">Library Active Issues List</a> for more information and the meaning of <a href="lwg-active.html#WP">WP</a> status.</em></p>
<h3 id="4054"><a href="lwg-defects.html#4054">4054</a>. Repeating a <code>repeat_view</code> should repeat the view</h3>
<p><b>Section:</b> 25.6.5.1 <a href="https://wg21.link/range.repeat.overview">[range.repeat.overview]</a> <b>Status:</b> <a href="lwg-active.html#WP">WP</a>
 <b>Submitter:</b> Tim Song <b>Opened:</b> 2024-02-12 <b>Last modified:</b> 2024-04-02</p>
<p><b>Priority: </b>Not Prioritized
</p>
<p><b>View all issues with</b> <a href="lwg-status.html#WP">WP</a> status.</p>
<p><b>Discussion:</b></p>
<p>
<code>views::repeat(views::repeat(5))</code> should be a view of <code>repeat_view</code>s, but it's currently a view of 
<code>ints</code> due to the use of CTAD in the specification of <code>views::repeat</code>.
</p>

<p><i>[2024-03-12; Reflector poll]</i></p>

<p>
Set status to Tentatively Ready after seven votes in favour during reflector poll.
</p>

<p><i>[Tokyo 2024-03-23; Status changed: Voting &rarr; WP.]</i></p>



<p id="res-4054"><b>Proposed resolution:</b></p>
<p>
This wording is relative to <a href="https://wg21.link/N4971" title=" Working Draft, Programming Languages — C++">N4971</a>.
</p>

<ol>
<li><p>Modify 25.6.5.1 <a href="https://wg21.link/range.repeat.overview">[range.repeat.overview]</a> as indicated:</p>

<blockquote>
<p>
-1- <code>repeat_view</code> generates a sequence of elements by repeatedly producing the same value.
<p/>
-2- The name <code>views::repeat</code> denotes a customization point object (16.3.3.3.5 <a href="https://wg21.link/customization.point.object">[customization.point.object]</a>). 
Given subexpressions <code>E</code> and <code>F</code>, the expressions <code>views::repeat(E)</code> and <code>views::repeat(E, F)</code> 
are expression-equivalent to <code>repeat_view<ins>&lt;decay_t&lt;decltype((E))&gt;&gt;</ins>(E)</code> and 
<code>repeat_view(E, F)</code>, respectively.
</p>
</blockquote>
</li>
</ol>





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