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<title>Issue 682: basic_regex ctor takes InputIterator or ForwardIterator?</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#CD1">CD1</a> status.</em></p>
<h3 id="682"><a href="lwg-defects.html#682">682</a>. basic_regex ctor takes InputIterator or ForwardIterator?</h3>
<p><b>Section:</b> 28.6.7.2 <a href="https://wg21.link/re.regex.construct">[re.regex.construct]</a> <b>Status:</b> <a href="lwg-active.html#CD1">CD1</a>
 <b>Submitter:</b> Eric Niebler <b>Opened:</b> 2007-06-03 <b>Last modified:</b> 2016-01-28</p>
<p><b>Priority: </b>Not Prioritized
</p>
<p><b>View other</b> <a href="lwg-index-open.html#re.regex.construct">active issues</a> in [re.regex.construct].</p>
<p><b>View all other</b> <a href="lwg-index.html#re.regex.construct">issues</a> in [re.regex.construct].</p>
<p><b>View all issues with</b> <a href="lwg-status.html#CD1">CD1</a> status.</p>
<p><b>Discussion:</b></p>
<p>
Looking at N2284, 28.6.7 <a href="https://wg21.link/re.regex">[re.regex]</a>, p3 <code>basic_regex</code> class template synopsis shows this 
constructor: 
</p>
<blockquote><pre>
template &lt;class InputIterator&gt;
     basic_regex(InputIterator first, InputIterator last, 
                 flag_type f = regex_constants::ECMAScript);
</pre></blockquote>

<p>
In 28.6.7.2 <a href="https://wg21.link/re.regex.construct">[re.regex.construct]</a>, p15, the constructor appears with this signature: 
</p>

<blockquote><pre>
template &lt;class ForwardIterator&gt;
     basic_regex(ForwardIterator first, ForwardIterator last, 
                 flag_type f = regex_constants::ECMAScript);
</pre></blockquote>

<p>
<code>ForwardIterator</code> is probably correct, so the synopsis is wrong.
</p>

<p><i>[
John adds:
]</i></p>


<blockquote>
<p>
I think either could be implemented?  Although an input iterator would 
probably require an internal copy of the string being made.
</p>
<p>
I have no strong feelings either way, although I think my original intent 
was <code>InputIterator</code>. 
</p>
</blockquote>


<p id="res-682"><b>Proposed resolution:</b></p>
<p>
Adopt the proposed resolution in
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2409.pdf">N2409</a>.
</p>


<p><i>[
Kona (2007): The LWG adopted the proposed resolution of N2409 for this issue.
The LWG voted to accelerate this issue to Ready status to be voted into the WP at Kona.
]</i></p>





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