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<title>Issue 3713: Sorted with respect to comparator (only)</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#C++23">C++23</a> status.</em></p>
<h3 id="3713"><a href="lwg-defects.html#3713">3713</a>. Sorted with respect to comparator (only)</h3>
<p><b>Section:</b> 26.8.1 <a href="https://wg21.link/alg.sorting.general">[alg.sorting.general]</a> <b>Status:</b> <a href="lwg-active.html#C++23">C++23</a>
 <b>Submitter:</b> Casey Carter <b>Opened:</b> 2022-06-10 <b>Last modified:</b> 2023-11-22</p>
<p><b>Priority: </b>Not Prioritized
</p>
<p><b>View all issues with</b> <a href="lwg-status.html#C++23">C++23</a> status.</p>
<p><b>Discussion:</b></p>
<p>
<a href="https://wg21.link/P0896R4" title=" The One Ranges Proposal">P0896R4</a> changed the term of art "sorted with respect to comparator" defined in 
26.8.1 <a href="https://wg21.link/alg.sorting.general">[alg.sorting.general]</a> paragraph 5 to "sorted with respect to comparator and projection." 
That proposal updated the algorithm specifications consistently. However, there were uses of the old 
term outside of 26 <a href="https://wg21.link/algorithms">[algorithms]</a> that are now without meaning. We should bring back the term 
"sorted with respect to comparator" to fix that lack.
</p>

<p><i>[2022-06-21; Reflector poll]</i></p>

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

<p><i>[2022-07-15; LWG telecon: move to Ready]</i></p>


<p><i>[2022-07-25 Approved at July 2022 virtual plenary. Status changed: Ready &rarr; WP.]</i></p>



<p id="res-3713"><b>Proposed resolution:</b></p>
<p>
This wording is relative to <a href="https://wg21.link/N4910" title=" Working Draft, Standard for Programming Language C++">N4910</a>.
</p>

<ol>
<li><p>Modify 26.8.1 <a href="https://wg21.link/alg.sorting.general">[alg.sorting.general]</a> as indicated:</p>

<blockquote>
<p>
-5- A sequence is <i>sorted with respect to a <code>comp</code> and <code>proj</code></i> for a comparator and projection 
<code>comp</code> and <code>proj</code> if for every iterator <code>i</code> pointing to the sequence and every non-negative 
integer <code>n</code> such that <code>i + n</code> is a valid iterator pointing to an element of the sequence,
</p>
<blockquote><pre>
bool(invoke(comp, invoke(proj, *(i + n)), invoke(proj, *i)))
</pre></blockquote>
<p>
is <code>false</code>.
<p/>
<ins>-?- A sequence is <i>sorted with respect to a comparator <code>comp</code></i> for a comparator <code>comp</code> 
if it is sorted with respect to <code>comp</code> and <code>identity{}</code> (the identity projection).</ins>
</p>
</blockquote>
</li>

</ol>





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