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[SVN r29099]
This commit is contained in:
Dave Abrahams
@ -3,7 +3,7 @@
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<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
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<meta name="generator" content="Docutils 0.3.6: http://docutils.sourceforge.net/" />
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<meta name="generator" content="Docutils 0.3.8: http://docutils.sourceforge.net/" />
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<title>New Iterator Concepts</title>
|
||||
<meta name="author" content="David Abrahams, Jeremy Siek, Thomas Witt" />
|
||||
<meta name="organization" content="Boost Consulting, Indiana University Open Systems Lab, Zephyr Associates, Inc." />
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@ -12,6 +12,7 @@
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||||
<link rel="stylesheet" href="default.css" type="text/css" />
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</head>
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||||
<body>
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||||
<div class="document" id="new-iterator-concepts">
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<h1 class="title">New Iterator Concepts</h1>
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<table class="docinfo" frame="void" rules="none">
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<col class="docinfo-name" />
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@ -36,10 +37,9 @@ revision of paper <a class="reference" href="http://anubis.dkuug.dk/jtc1/sc22/wg
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2003.</td></tr>
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</tbody>
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</table>
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||||
<div class="document" id="new-iterator-concepts">
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<!-- Version 1.25 of this ReStructuredText document is the same as
|
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n1550_, the paper accepted by the LWG. -->
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||||
<table class="field-list" frame="void" rules="none">
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||||
<table class="docutils field-list" frame="void" rules="none">
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<col class="field-name" />
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<col class="field-body" />
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<tbody valign="top">
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@ -59,7 +59,7 @@ of iterators that are used in practice.</td>
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<li><a class="reference" href="#possible-but-not-proposed-changes-to-the-working-paper" id="id3" name="id3">Possible (but not proposed) Changes to the Working Paper</a><ul>
|
||||
<li><a class="reference" href="#changes-to-algorithm-requirements" id="id4" name="id4">Changes to Algorithm Requirements</a></li>
|
||||
<li><a class="reference" href="#deprecations" id="id5" name="id5">Deprecations</a></li>
|
||||
<li><a class="reference" href="#vector-bool" id="id6" name="id6"><tt class="literal"><span class="pre">vector<bool></span></tt></a></li>
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<li><a class="reference" href="#vector-bool" id="id6" name="id6"><tt class="docutils literal"><span class="pre">vector<bool></span></tt></a></li>
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</ul>
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</li>
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</ul>
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@ -107,7 +107,7 @@ geared towards iterator traversal (hence the category names), while
|
||||
requirements that address value access sneak in at various places. The
|
||||
following table gives a summary of the current value access
|
||||
requirements in the iterator categories.</p>
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<table border="1" class="table">
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<table border="1" class="docutils">
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<colgroup>
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<col width="31%" />
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<col width="69%" />
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@ -118,17 +118,17 @@ requirements in the iterator categories.</p>
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</thead>
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<tbody valign="top">
|
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<tr><td>Output Iterator</td>
|
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<td><tt class="literal"><span class="pre">*i</span> <span class="pre">=</span> <span class="pre">a</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">*i</span> <span class="pre">=</span> <span class="pre">a</span></tt></td>
|
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</tr>
|
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<tr><td>Input Iterator</td>
|
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<td><tt class="literal"><span class="pre">*i</span></tt> is convertible to <tt class="literal"><span class="pre">T</span></tt></td>
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<td><tt class="docutils literal"><span class="pre">*i</span></tt> is convertible to <tt class="docutils literal"><span class="pre">T</span></tt></td>
|
||||
</tr>
|
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<tr><td>Forward Iterator</td>
|
||||
<td><tt class="literal"><span class="pre">*i</span></tt> is <tt class="literal"><span class="pre">T&</span></tt> (or <tt class="literal"><span class="pre">const</span> <span class="pre">T&</span></tt> once <a class="reference" href="http://anubis.dkuug.dk/JTC1/SC22/WG21/docs/lwg-active.html#200">issue 200</a>
|
||||
<td><tt class="docutils literal"><span class="pre">*i</span></tt> is <tt class="docutils literal"><span class="pre">T&</span></tt> (or <tt class="docutils literal"><span class="pre">const</span> <span class="pre">T&</span></tt> once <a class="reference" href="http://anubis.dkuug.dk/JTC1/SC22/WG21/docs/lwg-active.html#200">issue 200</a>
|
||||
is resolved)</td>
|
||||
</tr>
|
||||
<tr><td>Random Access Iterator</td>
|
||||
<td><tt class="literal"><span class="pre">i[n]</span></tt> is convertible to <tt class="literal"><span class="pre">T</span></tt> (also <tt class="literal"><span class="pre">i[n]</span> <span class="pre">=</span> <span class="pre">t</span></tt>
|
||||
<td><tt class="docutils literal"><span class="pre">i[n]</span></tt> is convertible to <tt class="docutils literal"><span class="pre">T</span></tt> (also <tt class="docutils literal"><span class="pre">i[n]</span> <span class="pre">=</span> <span class="pre">t</span></tt>
|
||||
is required for mutable iterators once <a class="reference" href="http://anubis.dkuug.dk/JTC1/SC22/WG21/docs/lwg-active.html#299">issue 299</a>
|
||||
is resolved)</td>
|
||||
</tr>
|
||||
@ -136,30 +136,30 @@ is resolved)</td>
|
||||
</table>
|
||||
<p>Because iterator traversal and value access are mixed together in a
|
||||
single hierarchy, many useful iterators can not be appropriately
|
||||
categorized. For example, <tt class="literal"><span class="pre">vector<bool>::iterator</span></tt> is almost a
|
||||
random access iterator, but the return type is not <tt class="literal"><span class="pre">bool&</span></tt> (see
|
||||
categorized. For example, <tt class="docutils literal"><span class="pre">vector<bool>::iterator</span></tt> is almost a
|
||||
random access iterator, but the return type is not <tt class="docutils literal"><span class="pre">bool&</span></tt> (see
|
||||
<a class="reference" href="http://anubis.dkuug.dk/JTC1/SC22/WG21/docs/lwg-active.html#96">issue 96</a> and Herb Sutter's paper J16/99-0008 = WG21
|
||||
N1185). Therefore, the iterators of <tt class="literal"><span class="pre">vector<bool></span></tt> only meet the
|
||||
N1185). Therefore, the iterators of <tt class="docutils literal"><span class="pre">vector<bool></span></tt> only meet the
|
||||
requirements of input iterator and output iterator. This is so
|
||||
nonintuitive that the C++ standard contradicts itself on this point.
|
||||
In paragraph 23.2.4/1 it says that a <tt class="literal"><span class="pre">vector</span></tt> is a sequence that
|
||||
In paragraph 23.2.4/1 it says that a <tt class="docutils literal"><span class="pre">vector</span></tt> is a sequence that
|
||||
supports random access iterators.</p>
|
||||
<p>Another difficult-to-categorize iterator is the transform iterator, an
|
||||
adaptor which applies a unary function object to the dereferenced
|
||||
value of the some underlying iterator (see <a class="reference" href="http://www.boost.org/libs/utility/transform_iterator.htm">transform_iterator</a>).
|
||||
For unary functions such as <tt class="literal"><span class="pre">times</span></tt>, the return type of
|
||||
<tt class="literal"><span class="pre">operator*</span></tt> clearly needs to be the <tt class="literal"><span class="pre">result_type</span></tt> of the function
|
||||
For unary functions such as <tt class="docutils literal"><span class="pre">times</span></tt>, the return type of
|
||||
<tt class="docutils literal"><span class="pre">operator*</span></tt> clearly needs to be the <tt class="docutils literal"><span class="pre">result_type</span></tt> of the function
|
||||
object, which is typically not a reference. Because random access
|
||||
iterators are required to return lvalues from <tt class="literal"><span class="pre">operator*</span></tt>, if you
|
||||
wrap <tt class="literal"><span class="pre">int*</span></tt> with a transform iterator, you do not get a random
|
||||
iterators are required to return lvalues from <tt class="docutils literal"><span class="pre">operator*</span></tt>, if you
|
||||
wrap <tt class="docutils literal"><span class="pre">int*</span></tt> with a transform iterator, you do not get a random
|
||||
access iterator as might be expected, but an input iterator.</p>
|
||||
<p>A third example is found in the vertex and edge iterators of the
|
||||
<a class="reference" href="http://www.boost.org/libs/graph/doc/table_of_contents.html">Boost Graph Library</a>. These iterators return vertex and edge
|
||||
descriptors, which are lightweight handles created on-the-fly. They
|
||||
must be returned by-value. As a result, their current standard
|
||||
iterator category is <tt class="literal"><span class="pre">input_iterator_tag</span></tt>, which means that,
|
||||
iterator category is <tt class="docutils literal"><span class="pre">input_iterator_tag</span></tt>, which means that,
|
||||
strictly speaking, you could not use these iterators with algorithms
|
||||
like <tt class="literal"><span class="pre">min_element()</span></tt>. As a temporary solution, the concept
|
||||
like <tt class="docutils literal"><span class="pre">min_element()</span></tt>. As a temporary solution, the concept
|
||||
<a class="reference" href="http://www.boost.org/libs/utility/MultiPassInputIterator.html">Multi-Pass Input Iterator</a> was introduced to describe the vertex and
|
||||
edge descriptors, but as the design notes for the concept suggest, a
|
||||
better solution is needed.</p>
|
||||
@ -206,57 +206,57 @@ These changes are phrased as textual substitutions, listing the
|
||||
algorithms to which each textual substitution applies.</p>
|
||||
<p>Forward Iterator -> Forward Traversal Iterator and Readable Iterator</p>
|
||||
<blockquote>
|
||||
<tt class="literal"><span class="pre">find_end,</span> <span class="pre">adjacent_find,</span> <span class="pre">search,</span> <span class="pre">search_n,</span> <span class="pre">rotate_copy,</span>
|
||||
<tt class="docutils literal"><span class="pre">find_end,</span> <span class="pre">adjacent_find,</span> <span class="pre">search,</span> <span class="pre">search_n,</span> <span class="pre">rotate_copy,</span>
|
||||
<span class="pre">lower_bound,</span> <span class="pre">upper_bound,</span> <span class="pre">equal_range,</span> <span class="pre">binary_search,</span>
|
||||
<span class="pre">min_element,</span> <span class="pre">max_element</span></tt></blockquote>
|
||||
<p>Forward Iterator (1) -> Single Pass Iterator and Readable Iterator,
|
||||
Forward Iterator (2) -> Forward Traversal Iterator and Readable Iterator</p>
|
||||
<blockquote>
|
||||
<tt class="literal"><span class="pre">find_first_of</span></tt></blockquote>
|
||||
<tt class="docutils literal"><span class="pre">find_first_of</span></tt></blockquote>
|
||||
<p>Forward Iterator -> Readable Iterator and Writable Iterator</p>
|
||||
<blockquote>
|
||||
<tt class="literal"><span class="pre">iter_swap</span></tt></blockquote>
|
||||
<tt class="docutils literal"><span class="pre">iter_swap</span></tt></blockquote>
|
||||
<p>Forward Iterator -> Single Pass Iterator and Writable Iterator</p>
|
||||
<blockquote>
|
||||
<tt class="literal"><span class="pre">fill,</span> <span class="pre">generate</span></tt></blockquote>
|
||||
<tt class="docutils literal"><span class="pre">fill,</span> <span class="pre">generate</span></tt></blockquote>
|
||||
<p>Forward Iterator -> Forward Traversal Iterator and Swappable Iterator</p>
|
||||
<blockquote>
|
||||
<tt class="literal"><span class="pre">rotate</span></tt></blockquote>
|
||||
<tt class="docutils literal"><span class="pre">rotate</span></tt></blockquote>
|
||||
<p>Forward Iterator (1) -> Swappable Iterator and Single Pass Iterator,
|
||||
Forward Iterator (2) -> Swappable Iterator and Incrementable Iterator</p>
|
||||
<blockquote>
|
||||
<tt class="literal"><span class="pre">swap_ranges</span></tt></blockquote>
|
||||
<dl>
|
||||
<tt class="docutils literal"><span class="pre">swap_ranges</span></tt></blockquote>
|
||||
<dl class="docutils">
|
||||
<dt>Forward Iterator -> Forward Traversal Iterator and Readable Iterator and Writable Iterator</dt>
|
||||
<dd><tt class="literal"><span class="pre">remove,</span> <span class="pre">remove_if,</span> <span class="pre">unique</span></tt></dd>
|
||||
<dd><tt class="docutils literal"><span class="pre">remove,</span> <span class="pre">remove_if,</span> <span class="pre">unique</span></tt></dd>
|
||||
</dl>
|
||||
<p>Forward Iterator -> Single Pass Iterator and Readable Iterator and Writable Iterator</p>
|
||||
<blockquote>
|
||||
<tt class="literal"><span class="pre">replace,</span> <span class="pre">replace_if</span></tt></blockquote>
|
||||
<dl>
|
||||
<tt class="docutils literal"><span class="pre">replace,</span> <span class="pre">replace_if</span></tt></blockquote>
|
||||
<dl class="docutils">
|
||||
<dt>Bidirectional Iterator -> Bidirectional Traversal Iterator and Swappable Iterator</dt>
|
||||
<dd><tt class="literal"><span class="pre">reverse</span></tt></dd>
|
||||
<dd><tt class="docutils literal"><span class="pre">reverse</span></tt></dd>
|
||||
<dt>Bidirectional Iterator -> Bidirectional Traversal Iterator and Readable and Swappable Iterator</dt>
|
||||
<dd><tt class="literal"><span class="pre">partition</span></tt></dd>
|
||||
<dd><tt class="docutils literal"><span class="pre">partition</span></tt></dd>
|
||||
</dl>
|
||||
<p>Bidirectional Iterator (1) -> Bidirectional Traversal Iterator and Readable Iterator,
|
||||
Bidirectional Iterator (2) -> Bidirectional Traversal Iterator and Writable Iterator</p>
|
||||
<blockquote>
|
||||
<tt class="literal"><span class="pre">copy_backwards</span></tt></blockquote>
|
||||
<dl>
|
||||
<tt class="docutils literal"><span class="pre">copy_backwards</span></tt></blockquote>
|
||||
<dl class="docutils">
|
||||
<dt>Bidirectional Iterator -> Bidirectional Traversal Iterator and Swappable Iterator and Readable Iterator</dt>
|
||||
<dd><tt class="literal"><span class="pre">next_permutation,</span> <span class="pre">prev_permutation</span></tt></dd>
|
||||
<dd><tt class="docutils literal"><span class="pre">next_permutation,</span> <span class="pre">prev_permutation</span></tt></dd>
|
||||
<dt>Bidirectional Iterator -> Bidirectional Traversal Iterator and Readable Iterator and Writable Iterator</dt>
|
||||
<dd><tt class="literal"><span class="pre">stable_partition,</span> <span class="pre">inplace_merge</span></tt></dd>
|
||||
<dd><tt class="docutils literal"><span class="pre">stable_partition,</span> <span class="pre">inplace_merge</span></tt></dd>
|
||||
<dt>Bidirectional Iterator -> Bidirectional Traversal Iterator and Readable Iterator</dt>
|
||||
<dd><tt class="literal"><span class="pre">reverse_copy</span></tt></dd>
|
||||
<dd><tt class="docutils literal"><span class="pre">reverse_copy</span></tt></dd>
|
||||
<dt>Random Access Iterator -> Random Access Traversal Iterator and Readable and Writable Iterator</dt>
|
||||
<dd><tt class="literal"><span class="pre">random_shuffle,</span> <span class="pre">sort,</span> <span class="pre">stable_sort,</span> <span class="pre">partial_sort,</span> <span class="pre">nth_element,</span> <span class="pre">push_heap,</span> <span class="pre">pop_heap</span>
|
||||
<dd><tt class="docutils literal"><span class="pre">random_shuffle,</span> <span class="pre">sort,</span> <span class="pre">stable_sort,</span> <span class="pre">partial_sort,</span> <span class="pre">nth_element,</span> <span class="pre">push_heap,</span> <span class="pre">pop_heap</span>
|
||||
<span class="pre">make_heap,</span> <span class="pre">sort_heap</span></tt></dd>
|
||||
<dt>Input Iterator (2) -> Incrementable Iterator and Readable Iterator</dt>
|
||||
<dd><tt class="literal"><span class="pre">equal,</span> <span class="pre">mismatch</span></tt></dd>
|
||||
<dd><tt class="docutils literal"><span class="pre">equal,</span> <span class="pre">mismatch</span></tt></dd>
|
||||
<dt>Input Iterator (2) -> Incrementable Iterator and Readable Iterator</dt>
|
||||
<dd><tt class="literal"><span class="pre">transform</span></tt></dd>
|
||||
<dd><tt class="docutils literal"><span class="pre">transform</span></tt></dd>
|
||||
</dl>
|
||||
</div>
|
||||
<div class="section" id="deprecations">
|
||||
@ -267,9 +267,9 @@ std::iterator_traits, since it will be superceded by individual
|
||||
traits metafunctions.</p>
|
||||
</div>
|
||||
<div class="section" id="vector-bool">
|
||||
<h3><a class="toc-backref" href="#id6" name="vector-bool"><tt class="literal"><span class="pre">vector<bool></span></tt></a></h3>
|
||||
<h3><a class="toc-backref" href="#id6" name="vector-bool"><tt class="docutils literal"><span class="pre">vector<bool></span></tt></a></h3>
|
||||
<p>For the next working paper (but not for TR1), the committee should
|
||||
consider reclassifying <tt class="literal"><span class="pre">vector<bool>::iterator</span></tt> as a Random
|
||||
consider reclassifying <tt class="docutils literal"><span class="pre">vector<bool>::iterator</span></tt> as a Random
|
||||
Access Traversal Iterator and Readable Iterator and Writable
|
||||
Iterator.</p>
|
||||
</div>
|
||||
@ -285,9 +285,9 @@ of concepts handles the syntax and semantics of value access:</p>
|
||||
<li>Swappable Iterator</li>
|
||||
<li>Lvalue Iterator</li>
|
||||
</ul>
|
||||
<p>The access concepts describe requirements related to <tt class="literal"><span class="pre">operator*</span></tt> and
|
||||
<tt class="literal"><span class="pre">operator-></span></tt>, including the <tt class="literal"><span class="pre">value_type</span></tt>, <tt class="literal"><span class="pre">reference</span></tt>, and
|
||||
<tt class="literal"><span class="pre">pointer</span></tt> associated types.</p>
|
||||
<p>The access concepts describe requirements related to <tt class="docutils literal"><span class="pre">operator*</span></tt> and
|
||||
<tt class="docutils literal"><span class="pre">operator-></span></tt>, including the <tt class="docutils literal"><span class="pre">value_type</span></tt>, <tt class="docutils literal"><span class="pre">reference</span></tt>, and
|
||||
<tt class="docutils literal"><span class="pre">pointer</span></tt> associated types.</p>
|
||||
<p>The other set of concepts handles traversal:</p>
|
||||
<ul class="simple">
|
||||
<li>Incrementable Iterator</li>
|
||||
@ -298,30 +298,30 @@ of concepts handles the syntax and semantics of value access:</p>
|
||||
</ul>
|
||||
<p>The refinement relationships for the traversal concepts are in the
|
||||
following diagram.</p>
|
||||
<p><img alt="traversal.png" src="traversal.png" /></p>
|
||||
<div class="image"><img alt="traversal.png" src="traversal.png" /></div>
|
||||
<p>In addition to the iterator movement operators, such as
|
||||
<tt class="literal"><span class="pre">operator++</span></tt>, the traversal concepts also include requirements on
|
||||
position comparison such as <tt class="literal"><span class="pre">operator==</span></tt> and <tt class="literal"><span class="pre">operator<</span></tt>. The
|
||||
<tt class="docutils literal"><span class="pre">operator++</span></tt>, the traversal concepts also include requirements on
|
||||
position comparison such as <tt class="docutils literal"><span class="pre">operator==</span></tt> and <tt class="docutils literal"><span class="pre">operator<</span></tt>. The
|
||||
reason for the fine grain slicing of the concepts into the
|
||||
Incrementable and Single Pass is to provide concepts that are exact
|
||||
matches with the original input and output iterator requirements.</p>
|
||||
<p>This proposal also includes a concept for specifying when an iterator
|
||||
is interoperable with another iterator, in the sense that <tt class="literal"><span class="pre">int*</span></tt> is
|
||||
interoperable with <tt class="literal"><span class="pre">int</span> <span class="pre">const*</span></tt>.</p>
|
||||
is interoperable with another iterator, in the sense that <tt class="docutils literal"><span class="pre">int*</span></tt> is
|
||||
interoperable with <tt class="docutils literal"><span class="pre">int</span> <span class="pre">const*</span></tt>.</p>
|
||||
<ul class="simple">
|
||||
<li>Interoperable Iterators</li>
|
||||
</ul>
|
||||
<p>The relationship between the new iterator concepts and the old are
|
||||
given in the following diagram.</p>
|
||||
<p><img alt="oldeqnew.png" src="oldeqnew.png" /></p>
|
||||
<div class="image"><img alt="oldeqnew.png" src="oldeqnew.png" /></div>
|
||||
<p>Like the old iterator requirements, we provide tags for purposes of
|
||||
dispatching based on the traversal concepts. The tags are related via
|
||||
inheritance so that a tag is convertible to another tag if the concept
|
||||
associated with the first tag is a refinement of the second tag.</p>
|
||||
<p>Our design reuses <tt class="literal"><span class="pre">iterator_traits<Iter>::iterator_category</span></tt> to
|
||||
<p>Our design reuses <tt class="docutils literal"><span class="pre">iterator_traits<Iter>::iterator_category</span></tt> to
|
||||
indicate an iterator's traversal capability. To specify
|
||||
capabilities not captured by any old-style iterator category, an
|
||||
iterator designer can use an <tt class="literal"><span class="pre">iterator_category</span></tt> type that is
|
||||
iterator designer can use an <tt class="docutils literal"><span class="pre">iterator_category</span></tt> type that is
|
||||
convertible to both the the most-derived old iterator category tag
|
||||
which fits, and the appropriate new iterator traversal tag.</p>
|
||||
<!-- dwa2003/1/2: Note that we are not *requiring* convertibility to
|
||||
@ -331,20 +331,20 @@ Old-style iterators still fit, after all. -->
|
||||
access concepts, in part because we could not find a way to
|
||||
automatically infer the right access tags for old-style iterators.
|
||||
An iterator's writability may be dependent on the assignability of
|
||||
its <tt class="literal"><span class="pre">value_type</span></tt> and there's no known way to detect whether an
|
||||
its <tt class="docutils literal"><span class="pre">value_type</span></tt> and there's no known way to detect whether an
|
||||
arbitrary type is assignable. Fortunately, the need for
|
||||
dispatching based on access capability is not as great as the need
|
||||
for dispatching based on traversal capability.</p>
|
||||
<p>A difficult design decision concerned the <tt class="literal"><span class="pre">operator[]</span></tt>. The direct
|
||||
approach for specifying <tt class="literal"><span class="pre">operator[]</span></tt> would have a return type of
|
||||
<tt class="literal"><span class="pre">reference</span></tt>; the same as <tt class="literal"><span class="pre">operator*</span></tt>. However, going in this
|
||||
<p>A difficult design decision concerned the <tt class="docutils literal"><span class="pre">operator[]</span></tt>. The direct
|
||||
approach for specifying <tt class="docutils literal"><span class="pre">operator[]</span></tt> would have a return type of
|
||||
<tt class="docutils literal"><span class="pre">reference</span></tt>; the same as <tt class="docutils literal"><span class="pre">operator*</span></tt>. However, going in this
|
||||
direction would mean that an iterator satisfying the old Random Access
|
||||
Iterator requirements would not necessarily be a model of Readable or
|
||||
Writable Lvalue Iterator. Instead we have chosen a design that
|
||||
matches the preferred resolution of <a class="reference" href="http://anubis.dkuug.dk/JTC1/SC22/WG21/docs/lwg-active.html#299">issue 299</a>: <tt class="literal"><span class="pre">operator[]</span></tt> is
|
||||
only required to return something convertible to the <tt class="literal"><span class="pre">value_type</span></tt>
|
||||
matches the preferred resolution of <a class="reference" href="http://anubis.dkuug.dk/JTC1/SC22/WG21/docs/lwg-active.html#299">issue 299</a>: <tt class="docutils literal"><span class="pre">operator[]</span></tt> is
|
||||
only required to return something convertible to the <tt class="docutils literal"><span class="pre">value_type</span></tt>
|
||||
(for a Readable Iterator), and is required to support assignment
|
||||
<tt class="literal"><span class="pre">i[n]</span> <span class="pre">=</span> <span class="pre">t</span></tt> (for a Writable Iterator).</p>
|
||||
<tt class="docutils literal"><span class="pre">i[n]</span> <span class="pre">=</span> <span class="pre">t</span></tt> (for a Writable Iterator).</p>
|
||||
</div>
|
||||
<div class="section" id="proposed-text">
|
||||
<h1><a class="toc-backref" href="#id8" name="proposed-text">Proposed Text</a></h1>
|
||||
@ -352,19 +352,19 @@ only required to return something convertible to the <tt class="literal"><span c
|
||||
<h2><a class="toc-backref" href="#id9" name="addition-to-lib-iterator-requirements">Addition to [lib.iterator.requirements]</a></h2>
|
||||
<div class="section" id="iterator-value-access-concepts-lib-iterator-value-access">
|
||||
<h3><a class="toc-backref" href="#id10" name="iterator-value-access-concepts-lib-iterator-value-access">Iterator Value Access Concepts [lib.iterator.value.access]</a></h3>
|
||||
<p>In the tables below, <tt class="literal"><span class="pre">X</span></tt> is an iterator type, <tt class="literal"><span class="pre">a</span></tt> is a constant
|
||||
object of type <tt class="literal"><span class="pre">X</span></tt>, <tt class="literal"><span class="pre">R</span></tt> is
|
||||
<tt class="literal"><span class="pre">std::iterator_traits<X>::reference</span></tt>, <tt class="literal"><span class="pre">T</span></tt> is
|
||||
<tt class="literal"><span class="pre">std::iterator_traits<X>::value_type</span></tt>, and <tt class="literal"><span class="pre">v</span></tt> is a constant
|
||||
object of type <tt class="literal"><span class="pre">T</span></tt>.</p>
|
||||
<p>In the tables below, <tt class="docutils literal"><span class="pre">X</span></tt> is an iterator type, <tt class="docutils literal"><span class="pre">a</span></tt> is a constant
|
||||
object of type <tt class="docutils literal"><span class="pre">X</span></tt>, <tt class="docutils literal"><span class="pre">R</span></tt> is
|
||||
<tt class="docutils literal"><span class="pre">std::iterator_traits<X>::reference</span></tt>, <tt class="docutils literal"><span class="pre">T</span></tt> is
|
||||
<tt class="docutils literal"><span class="pre">std::iterator_traits<X>::value_type</span></tt>, and <tt class="docutils literal"><span class="pre">v</span></tt> is a constant
|
||||
object of type <tt class="docutils literal"><span class="pre">T</span></tt>.</p>
|
||||
<a class="target" id="readable-iterator" name="readable-iterator"></a><div class="section" id="readable-iterators-lib-readable-iterators">
|
||||
<h4><a class="toc-backref" href="#id11" name="readable-iterators-lib-readable-iterators">Readable Iterators [lib.readable.iterators]</a></h4>
|
||||
<p>A class or built-in type <tt class="literal"><span class="pre">X</span></tt> models the <em>Readable Iterator</em> concept
|
||||
for value type <tt class="literal"><span class="pre">T</span></tt> if, in addition to <tt class="literal"><span class="pre">X</span></tt> being Assignable and
|
||||
<p>A class or built-in type <tt class="docutils literal"><span class="pre">X</span></tt> models the <em>Readable Iterator</em> concept
|
||||
for value type <tt class="docutils literal"><span class="pre">T</span></tt> if, in addition to <tt class="docutils literal"><span class="pre">X</span></tt> being Assignable and
|
||||
Copy Constructible, the following expressions are valid and respect
|
||||
the stated semantics. <tt class="literal"><span class="pre">U</span></tt> is the type of any specified member of
|
||||
type <tt class="literal"><span class="pre">T</span></tt>.</p>
|
||||
<table border="1" class="table">
|
||||
the stated semantics. <tt class="docutils literal"><span class="pre">U</span></tt> is the type of any specified member of
|
||||
type <tt class="docutils literal"><span class="pre">T</span></tt>.</p>
|
||||
<table border="1" class="docutils">
|
||||
<colgroup>
|
||||
<col width="28%" />
|
||||
<col width="20%" />
|
||||
@ -379,22 +379,22 @@ type <tt class="literal"><span class="pre">T</span></tt>.</p>
|
||||
</tr>
|
||||
</thead>
|
||||
<tbody valign="top">
|
||||
<tr><td><tt class="literal"><span class="pre">iterator_traits<X>::value_type</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">T</span></tt></td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">iterator_traits<X>::value_type</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">T</span></tt></td>
|
||||
<td>Any non-reference,
|
||||
non-cv-qualified type</td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">*a</span></tt></td>
|
||||
<td>Convertible to <tt class="literal"><span class="pre">T</span></tt></td>
|
||||
<td><dl class="first last">
|
||||
<dt>pre: <tt class="literal"><span class="pre">a</span></tt> is dereferenceable. If <tt class="literal"><span class="pre">a</span> <span class="pre">==</span> <span class="pre">b</span></tt> then <tt class="literal"><span class="pre">*a</span></tt></dt>
|
||||
<dd>is equivalent to <tt class="literal"><span class="pre">*b</span></tt>.</dd>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">*a</span></tt></td>
|
||||
<td>Convertible to <tt class="docutils literal"><span class="pre">T</span></tt></td>
|
||||
<td><dl class="first last docutils">
|
||||
<dt>pre: <tt class="docutils literal"><span class="pre">a</span></tt> is dereferenceable. If <tt class="docutils literal"><span class="pre">a</span> <span class="pre">==</span> <span class="pre">b</span></tt> then <tt class="docutils literal"><span class="pre">*a</span></tt></dt>
|
||||
<dd>is equivalent to <tt class="docutils literal"><span class="pre">*b</span></tt>.</dd>
|
||||
</dl>
|
||||
</td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">a->m</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">U&</span></tt></td>
|
||||
<td>pre: <tt class="literal"><span class="pre">pre:</span> <span class="pre">(*a).m</span></tt> is well-defined. Equivalent to <tt class="literal"><span class="pre">(*a).m</span></tt>.</td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">a->m</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">U&</span></tt></td>
|
||||
<td>pre: <tt class="docutils literal"><span class="pre">pre:</span> <span class="pre">(*a).m</span></tt> is well-defined. Equivalent to <tt class="docutils literal"><span class="pre">(*a).m</span></tt>.</td>
|
||||
</tr>
|
||||
</tbody>
|
||||
</table>
|
||||
@ -402,11 +402,11 @@ non-cv-qualified type</td>
|
||||
<a class="target" id="writable-iterator" name="writable-iterator"></a></div>
|
||||
<div class="section" id="writable-iterators-lib-writable-iterators">
|
||||
<h4><a class="toc-backref" href="#id12" name="writable-iterators-lib-writable-iterators">Writable Iterators [lib.writable.iterators]</a></h4>
|
||||
<p>A class or built-in type <tt class="literal"><span class="pre">X</span></tt> models the <em>Writable Iterator</em> concept
|
||||
if, in addition to <tt class="literal"><span class="pre">X</span></tt> being Copy Constructible, the following
|
||||
<p>A class or built-in type <tt class="docutils literal"><span class="pre">X</span></tt> models the <em>Writable Iterator</em> concept
|
||||
if, in addition to <tt class="docutils literal"><span class="pre">X</span></tt> being Copy Constructible, the following
|
||||
expressions are valid and respect the stated semantics. Writable
|
||||
Iterators have an associated <em>set of value types</em>.</p>
|
||||
<table border="1" class="table">
|
||||
<table border="1" class="docutils">
|
||||
<colgroup>
|
||||
<col width="37%" />
|
||||
<col width="21%" />
|
||||
@ -421,21 +421,21 @@ Iterators have an associated <em>set of value types</em>.</p>
|
||||
</tr>
|
||||
</thead>
|
||||
<tbody valign="top">
|
||||
<tr><td><tt class="literal"><span class="pre">*a</span> <span class="pre">=</span> <span class="pre">o</span></tt></td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">*a</span> <span class="pre">=</span> <span class="pre">o</span></tt></td>
|
||||
<td> </td>
|
||||
<td>pre: The type of <tt class="literal"><span class="pre">o</span></tt>
|
||||
<td>pre: The type of <tt class="docutils literal"><span class="pre">o</span></tt>
|
||||
is in the set of
|
||||
value types of <tt class="literal"><span class="pre">X</span></tt></td>
|
||||
value types of <tt class="docutils literal"><span class="pre">X</span></tt></td>
|
||||
</tr>
|
||||
</tbody>
|
||||
</table>
|
||||
</div>
|
||||
<div class="section" id="swappable-iterators-lib-swappable-iterators">
|
||||
<h4><a class="toc-backref" href="#id13" name="swappable-iterators-lib-swappable-iterators">Swappable Iterators [lib.swappable.iterators]</a></h4>
|
||||
<p>A class or built-in type <tt class="literal"><span class="pre">X</span></tt> models the <em>Swappable Iterator</em> concept
|
||||
if, in addition to <tt class="literal"><span class="pre">X</span></tt> being Copy Constructible, the following
|
||||
<p>A class or built-in type <tt class="docutils literal"><span class="pre">X</span></tt> models the <em>Swappable Iterator</em> concept
|
||||
if, in addition to <tt class="docutils literal"><span class="pre">X</span></tt> being Copy Constructible, the following
|
||||
expressions are valid and respect the stated semantics.</p>
|
||||
<table border="1" class="table">
|
||||
<table border="1" class="docutils">
|
||||
<colgroup>
|
||||
<col width="37%" />
|
||||
<col width="19%" />
|
||||
@ -450,8 +450,8 @@ expressions are valid and respect the stated semantics.</p>
|
||||
</tr>
|
||||
</thead>
|
||||
<tbody valign="top">
|
||||
<tr><td><tt class="literal"><span class="pre">iter_swap(a,</span> <span class="pre">b)</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">void</span></tt></td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">iter_swap(a,</span> <span class="pre">b)</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">void</span></tt></td>
|
||||
<td>the pointed to values are
|
||||
exchanged</td>
|
||||
</tr>
|
||||
@ -464,9 +464,9 @@ Iterator</em>. <em>--end note</em>]</p>
|
||||
<div class="section" id="lvalue-iterators-lib-lvalue-iterators">
|
||||
<h4><a class="toc-backref" href="#id14" name="lvalue-iterators-lib-lvalue-iterators">Lvalue Iterators [lib.lvalue.iterators]</a></h4>
|
||||
<p>The <em>Lvalue Iterator</em> concept adds the requirement that the return
|
||||
type of <tt class="literal"><span class="pre">operator*</span></tt> type be a reference to the value type of the
|
||||
type of <tt class="docutils literal"><span class="pre">operator*</span></tt> type be a reference to the value type of the
|
||||
iterator.</p>
|
||||
<table border="1" class="table">
|
||||
<table border="1" class="docutils">
|
||||
<colgroup>
|
||||
<col width="22%" />
|
||||
<col width="19%" />
|
||||
@ -481,35 +481,35 @@ iterator.</p>
|
||||
</tr>
|
||||
</thead>
|
||||
<tbody valign="top">
|
||||
<tr><td><tt class="literal"><span class="pre">*a</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">T&</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">T</span></tt> is <em>cv</em>
|
||||
<tt class="literal"><span class="pre">iterator_traits<X>::value_type</span></tt>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">*a</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">T&</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">T</span></tt> is <em>cv</em>
|
||||
<tt class="docutils literal"><span class="pre">iterator_traits<X>::value_type</span></tt>
|
||||
where <em>cv</em> is an optional
|
||||
cv-qualification. pre: <tt class="literal"><span class="pre">a</span></tt> is
|
||||
cv-qualification. pre: <tt class="docutils literal"><span class="pre">a</span></tt> is
|
||||
dereferenceable.</td>
|
||||
</tr>
|
||||
</tbody>
|
||||
</table>
|
||||
<p>If <tt class="literal"><span class="pre">X</span></tt> is a <a class="reference" href="#writable-iterator">Writable Iterator</a> then <tt class="literal"><span class="pre">a</span> <span class="pre">==</span> <span class="pre">b</span></tt> if and only if
|
||||
<tt class="literal"><span class="pre">*a</span></tt> is the same object as <tt class="literal"><span class="pre">*b</span></tt>. If <tt class="literal"><span class="pre">X</span></tt> is a <a class="reference" href="#readable-iterator">Readable
|
||||
Iterator</a> then <tt class="literal"><span class="pre">a</span> <span class="pre">==</span> <span class="pre">b</span></tt> implies <tt class="literal"><span class="pre">*a</span></tt> is the same object as
|
||||
<tt class="literal"><span class="pre">*b</span></tt>.</p>
|
||||
<p>If <tt class="docutils literal"><span class="pre">X</span></tt> is a <a class="reference" href="#writable-iterator">Writable Iterator</a> then <tt class="docutils literal"><span class="pre">a</span> <span class="pre">==</span> <span class="pre">b</span></tt> if and only if
|
||||
<tt class="docutils literal"><span class="pre">*a</span></tt> is the same object as <tt class="docutils literal"><span class="pre">*b</span></tt>. If <tt class="docutils literal"><span class="pre">X</span></tt> is a <a class="reference" href="#readable-iterator">Readable
|
||||
Iterator</a> then <tt class="docutils literal"><span class="pre">a</span> <span class="pre">==</span> <span class="pre">b</span></tt> implies <tt class="docutils literal"><span class="pre">*a</span></tt> is the same object as
|
||||
<tt class="docutils literal"><span class="pre">*b</span></tt>.</p>
|
||||
</div>
|
||||
</div>
|
||||
<div class="section" id="iterator-traversal-concepts-lib-iterator-traversal">
|
||||
<h3><a class="toc-backref" href="#id15" name="iterator-traversal-concepts-lib-iterator-traversal">Iterator Traversal Concepts [lib.iterator.traversal]</a></h3>
|
||||
<p>In the tables below, <tt class="literal"><span class="pre">X</span></tt> is an iterator type, <tt class="literal"><span class="pre">a</span></tt> and <tt class="literal"><span class="pre">b</span></tt> are
|
||||
constant objects of type <tt class="literal"><span class="pre">X</span></tt>, <tt class="literal"><span class="pre">r</span></tt> and <tt class="literal"><span class="pre">s</span></tt> are mutable objects of
|
||||
type <tt class="literal"><span class="pre">X</span></tt>, <tt class="literal"><span class="pre">T</span></tt> is <tt class="literal"><span class="pre">std::iterator_traits<X>::value_type</span></tt>, and
|
||||
<tt class="literal"><span class="pre">v</span></tt> is a constant object of type <tt class="literal"><span class="pre">T</span></tt>.</p>
|
||||
<p>In the tables below, <tt class="docutils literal"><span class="pre">X</span></tt> is an iterator type, <tt class="docutils literal"><span class="pre">a</span></tt> and <tt class="docutils literal"><span class="pre">b</span></tt> are
|
||||
constant objects of type <tt class="docutils literal"><span class="pre">X</span></tt>, <tt class="docutils literal"><span class="pre">r</span></tt> and <tt class="docutils literal"><span class="pre">s</span></tt> are mutable objects of
|
||||
type <tt class="docutils literal"><span class="pre">X</span></tt>, <tt class="docutils literal"><span class="pre">T</span></tt> is <tt class="docutils literal"><span class="pre">std::iterator_traits<X>::value_type</span></tt>, and
|
||||
<tt class="docutils literal"><span class="pre">v</span></tt> is a constant object of type <tt class="docutils literal"><span class="pre">T</span></tt>.</p>
|
||||
<div class="section" id="incrementable-iterators-lib-incrementable-iterators">
|
||||
<h4><a class="toc-backref" href="#id16" name="incrementable-iterators-lib-incrementable-iterators">Incrementable Iterators [lib.incrementable.iterators]</a></h4>
|
||||
<p>A class or built-in type <tt class="literal"><span class="pre">X</span></tt> models the <em>Incrementable Iterator</em>
|
||||
concept if, in addition to <tt class="literal"><span class="pre">X</span></tt> being Assignable and Copy
|
||||
<p>A class or built-in type <tt class="docutils literal"><span class="pre">X</span></tt> models the <em>Incrementable Iterator</em>
|
||||
concept if, in addition to <tt class="docutils literal"><span class="pre">X</span></tt> being Assignable and Copy
|
||||
Constructible, the following expressions are valid and respect the
|
||||
stated semantics.</p>
|
||||
<table border="1" class="table">
|
||||
<table border="1" class="docutils">
|
||||
<colgroup>
|
||||
<col width="39%" />
|
||||
<col width="38%" />
|
||||
@ -524,39 +524,39 @@ stated semantics.</p>
|
||||
</tr>
|
||||
</thead>
|
||||
<tbody valign="top">
|
||||
<tr><td><tt class="literal"><span class="pre">++r</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">X&</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">&r</span> <span class="pre">==</span> <span class="pre">&++r</span></tt></td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">++r</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">X&</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">&r</span> <span class="pre">==</span> <span class="pre">&++r</span></tt></td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">r++</span></tt></td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">r++</span></tt></td>
|
||||
<td> </td>
|
||||
<td> </td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">*r++</span></tt></td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">*r++</span></tt></td>
|
||||
<td> </td>
|
||||
<td> </td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">iterator_traversal<X>::type</span></tt></td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">iterator_traversal<X>::type</span></tt></td>
|
||||
<td>Convertible to
|
||||
<tt class="literal"><span class="pre">incrementable_traversal_tag</span></tt></td>
|
||||
<tt class="docutils literal"><span class="pre">incrementable_traversal_tag</span></tt></td>
|
||||
<td> </td>
|
||||
</tr>
|
||||
</tbody>
|
||||
</table>
|
||||
<p>If <tt class="literal"><span class="pre">X</span></tt> is a <a class="reference" href="#writable-iterator">Writable Iterator</a> then <tt class="literal"><span class="pre">X</span> <span class="pre">a(r++);</span></tt> is equivalent
|
||||
to <tt class="literal"><span class="pre">X</span> <span class="pre">a(r);</span> <span class="pre">++r;</span></tt> and <tt class="literal"><span class="pre">*r++</span> <span class="pre">=</span> <span class="pre">o</span></tt> is equivalent
|
||||
to <tt class="literal"><span class="pre">*r</span> <span class="pre">=</span> <span class="pre">o;</span> <span class="pre">++r</span></tt>.
|
||||
If <tt class="literal"><span class="pre">X</span></tt> is a <a class="reference" href="#readable-iterator">Readable Iterator</a> then <tt class="literal"><span class="pre">T</span> <span class="pre">z(*r++);</span></tt> is equivalent
|
||||
to <tt class="literal"><span class="pre">T</span> <span class="pre">z(*r);</span> <span class="pre">++r;</span></tt>.</p>
|
||||
<p>If <tt class="docutils literal"><span class="pre">X</span></tt> is a <a class="reference" href="#writable-iterator">Writable Iterator</a> then <tt class="docutils literal"><span class="pre">X</span> <span class="pre">a(r++);</span></tt> is equivalent
|
||||
to <tt class="docutils literal"><span class="pre">X</span> <span class="pre">a(r);</span> <span class="pre">++r;</span></tt> and <tt class="docutils literal"><span class="pre">*r++</span> <span class="pre">=</span> <span class="pre">o</span></tt> is equivalent
|
||||
to <tt class="docutils literal"><span class="pre">*r</span> <span class="pre">=</span> <span class="pre">o;</span> <span class="pre">++r</span></tt>.
|
||||
If <tt class="docutils literal"><span class="pre">X</span></tt> is a <a class="reference" href="#readable-iterator">Readable Iterator</a> then <tt class="docutils literal"><span class="pre">T</span> <span class="pre">z(*r++);</span></tt> is equivalent
|
||||
to <tt class="docutils literal"><span class="pre">T</span> <span class="pre">z(*r);</span> <span class="pre">++r;</span></tt>.</p>
|
||||
<!-- TR1: incrementable_iterator_tag changed to
|
||||
incrementable_traversal_tag for consistency. -->
|
||||
</div>
|
||||
<div class="section" id="single-pass-iterators-lib-single-pass-iterators">
|
||||
<h4><a class="toc-backref" href="#id17" name="single-pass-iterators-lib-single-pass-iterators">Single Pass Iterators [lib.single.pass.iterators]</a></h4>
|
||||
<p>A class or built-in type <tt class="literal"><span class="pre">X</span></tt> models the <em>Single Pass Iterator</em>
|
||||
<p>A class or built-in type <tt class="docutils literal"><span class="pre">X</span></tt> models the <em>Single Pass Iterator</em>
|
||||
concept if the following expressions are valid and respect the stated
|
||||
semantics.</p>
|
||||
<table border="1" class="table">
|
||||
<table border="1" class="docutils">
|
||||
<colgroup>
|
||||
<col width="32%" />
|
||||
<col width="29%" />
|
||||
@ -576,28 +576,28 @@ Pre-/Post-condition</th>
|
||||
</tr>
|
||||
</thead>
|
||||
<tbody valign="top">
|
||||
<tr><td><tt class="literal"><span class="pre">++r</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">X&</span></tt></td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">++r</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">X&</span></tt></td>
|
||||
<td> </td>
|
||||
<td>pre: <tt class="literal"><span class="pre">r</span></tt> is
|
||||
<td>pre: <tt class="docutils literal"><span class="pre">r</span></tt> is
|
||||
dereferenceable; post:
|
||||
<tt class="literal"><span class="pre">r</span></tt> is dereferenceable or
|
||||
<tt class="literal"><span class="pre">r</span></tt> is past-the-end</td>
|
||||
<tt class="docutils literal"><span class="pre">r</span></tt> is dereferenceable or
|
||||
<tt class="docutils literal"><span class="pre">r</span></tt> is past-the-end</td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">a</span> <span class="pre">==</span> <span class="pre">b</span></tt></td>
|
||||
<td>convertible to <tt class="literal"><span class="pre">bool</span></tt></td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">a</span> <span class="pre">==</span> <span class="pre">b</span></tt></td>
|
||||
<td>convertible to <tt class="docutils literal"><span class="pre">bool</span></tt></td>
|
||||
<td> </td>
|
||||
<td><tt class="literal"><span class="pre">==</span></tt> is an equivalence
|
||||
<td><tt class="docutils literal"><span class="pre">==</span></tt> is an equivalence
|
||||
relation over its domain</td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">a</span> <span class="pre">!=</span> <span class="pre">b</span></tt></td>
|
||||
<td>convertible to <tt class="literal"><span class="pre">bool</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">!(a</span> <span class="pre">==</span> <span class="pre">b)</span></tt></td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">a</span> <span class="pre">!=</span> <span class="pre">b</span></tt></td>
|
||||
<td>convertible to <tt class="docutils literal"><span class="pre">bool</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">!(a</span> <span class="pre">==</span> <span class="pre">b)</span></tt></td>
|
||||
<td> </td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">iterator_traversal<X>::type</span></tt></td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">iterator_traversal<X>::type</span></tt></td>
|
||||
<td>Convertible to
|
||||
<tt class="literal"><span class="pre">single_pass_traversal_tag</span></tt></td>
|
||||
<tt class="docutils literal"><span class="pre">single_pass_traversal_tag</span></tt></td>
|
||||
<td> </td>
|
||||
<td> </td>
|
||||
</tr>
|
||||
@ -608,11 +608,11 @@ single_pass_traversal_tag for consistency -->
|
||||
</div>
|
||||
<div class="section" id="forward-traversal-iterators-lib-forward-traversal-iterators">
|
||||
<h4><a class="toc-backref" href="#id18" name="forward-traversal-iterators-lib-forward-traversal-iterators">Forward Traversal Iterators [lib.forward.traversal.iterators]</a></h4>
|
||||
<p>A class or built-in type <tt class="literal"><span class="pre">X</span></tt> models the <em>Forward Traversal Iterator</em>
|
||||
concept if, in addition to <tt class="literal"><span class="pre">X</span></tt> meeting the requirements of Default
|
||||
<p>A class or built-in type <tt class="docutils literal"><span class="pre">X</span></tt> models the <em>Forward Traversal Iterator</em>
|
||||
concept if, in addition to <tt class="docutils literal"><span class="pre">X</span></tt> meeting the requirements of Default
|
||||
Constructible and Single Pass Iterator, the following expressions are
|
||||
valid and respect the stated semantics.</p>
|
||||
<table border="1" class="table">
|
||||
<table border="1" class="docutils">
|
||||
<colgroup>
|
||||
<col width="38%" />
|
||||
<col width="34%" />
|
||||
@ -627,25 +627,25 @@ valid and respect the stated semantics.</p>
|
||||
</tr>
|
||||
</thead>
|
||||
<tbody valign="top">
|
||||
<tr><td><tt class="literal"><span class="pre">X</span> <span class="pre">u;</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">X&</span></tt></td>
|
||||
<td>note: <tt class="literal"><span class="pre">u</span></tt> may have a
|
||||
<tr><td><tt class="docutils literal"><span class="pre">X</span> <span class="pre">u;</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">X&</span></tt></td>
|
||||
<td>note: <tt class="docutils literal"><span class="pre">u</span></tt> may have a
|
||||
singular value.</td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">++r</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">X&</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">r</span> <span class="pre">==</span> <span class="pre">s</span></tt> and <tt class="literal"><span class="pre">r</span></tt> is
|
||||
<tr><td><tt class="docutils literal"><span class="pre">++r</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">X&</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">r</span> <span class="pre">==</span> <span class="pre">s</span></tt> and <tt class="docutils literal"><span class="pre">r</span></tt> is
|
||||
dereferenceable implies
|
||||
<tt class="literal"><span class="pre">++r</span> <span class="pre">==</span> <span class="pre">++s.</span></tt></td>
|
||||
<tt class="docutils literal"><span class="pre">++r</span> <span class="pre">==</span> <span class="pre">++s.</span></tt></td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">iterator_traits<X>::difference_type</span></tt></td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">iterator_traits<X>::difference_type</span></tt></td>
|
||||
<td>A signed integral type representing
|
||||
the distance between iterators</td>
|
||||
<td> </td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">iterator_traversal<X>::type</span></tt></td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">iterator_traversal<X>::type</span></tt></td>
|
||||
<td>Convertible to
|
||||
<tt class="literal"><span class="pre">forward_traversal_tag</span></tt></td>
|
||||
<tt class="docutils literal"><span class="pre">forward_traversal_tag</span></tt></td>
|
||||
<td> </td>
|
||||
</tr>
|
||||
</tbody>
|
||||
@ -655,11 +655,11 @@ forward_traversal_tag for consistency -->
|
||||
</div>
|
||||
<div class="section" id="bidirectional-traversal-iterators-lib-bidirectional-traversal-iterators">
|
||||
<h4><a class="toc-backref" href="#id19" name="bidirectional-traversal-iterators-lib-bidirectional-traversal-iterators">Bidirectional Traversal Iterators [lib.bidirectional.traversal.iterators]</a></h4>
|
||||
<p>A class or built-in type <tt class="literal"><span class="pre">X</span></tt> models the <em>Bidirectional Traversal
|
||||
Iterator</em> concept if, in addition to <tt class="literal"><span class="pre">X</span></tt> meeting the requirements of
|
||||
<p>A class or built-in type <tt class="docutils literal"><span class="pre">X</span></tt> models the <em>Bidirectional Traversal
|
||||
Iterator</em> concept if, in addition to <tt class="docutils literal"><span class="pre">X</span></tt> meeting the requirements of
|
||||
Forward Traversal Iterator, the following expressions are valid and
|
||||
respect the stated semantics.</p>
|
||||
<table border="1" class="table">
|
||||
<table border="1" class="docutils">
|
||||
<colgroup>
|
||||
<col width="33%" />
|
||||
<col width="32%" />
|
||||
@ -679,22 +679,22 @@ Pre-/Post-condition</th>
|
||||
</tr>
|
||||
</thead>
|
||||
<tbody valign="top">
|
||||
<tr><td><tt class="literal"><span class="pre">--r</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">X&</span></tt></td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">--r</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">X&</span></tt></td>
|
||||
<td> </td>
|
||||
<td><p class="first">pre: there exists
|
||||
<tt class="literal"><span class="pre">s</span></tt> such that <tt class="literal"><span class="pre">r</span>
|
||||
<tt class="docutils literal"><span class="pre">s</span></tt> such that <tt class="docutils literal"><span class="pre">r</span>
|
||||
<span class="pre">==</span> <span class="pre">++s</span></tt>. post:
|
||||
<tt class="literal"><span class="pre">s</span></tt> is
|
||||
<tt class="docutils literal"><span class="pre">s</span></tt> is
|
||||
dereferenceable.</p>
|
||||
<p class="last"><tt class="literal"><span class="pre">++(--r)</span> <span class="pre">==</span> <span class="pre">r</span></tt>.
|
||||
<tt class="literal"><span class="pre">--r</span> <span class="pre">==</span> <span class="pre">--s</span></tt>
|
||||
implies <tt class="literal"><span class="pre">r</span> <span class="pre">==</span>
|
||||
<span class="pre">s</span></tt>. <tt class="literal"><span class="pre">&r</span> <span class="pre">==</span> <span class="pre">&--r</span></tt>.</p>
|
||||
<p class="last"><tt class="docutils literal"><span class="pre">++(--r)</span> <span class="pre">==</span> <span class="pre">r</span></tt>.
|
||||
<tt class="docutils literal"><span class="pre">--r</span> <span class="pre">==</span> <span class="pre">--s</span></tt>
|
||||
implies <tt class="docutils literal"><span class="pre">r</span> <span class="pre">==</span>
|
||||
<span class="pre">s</span></tt>. <tt class="docutils literal"><span class="pre">&r</span> <span class="pre">==</span> <span class="pre">&--r</span></tt>.</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">r--</span></tt></td>
|
||||
<td>convertible to <tt class="literal"><span class="pre">const</span> <span class="pre">X&</span></tt></td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">r--</span></tt></td>
|
||||
<td>convertible to <tt class="docutils literal"><span class="pre">const</span> <span class="pre">X&</span></tt></td>
|
||||
<td><pre class="first last literal-block">
|
||||
{
|
||||
X tmp = r;
|
||||
@ -705,9 +705,9 @@ implies <tt class="literal"><span class="pre">r</span> <span class="pre">==</spa
|
||||
</td>
|
||||
<td> </td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">iterator_traversal<X>::type</span></tt></td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">iterator_traversal<X>::type</span></tt></td>
|
||||
<td>Convertible to
|
||||
<tt class="literal"><span class="pre">bidirectional_traversal_tag</span></tt></td>
|
||||
<tt class="docutils literal"><span class="pre">bidirectional_traversal_tag</span></tt></td>
|
||||
<td> </td>
|
||||
<td> </td>
|
||||
</tr>
|
||||
@ -718,12 +718,12 @@ bidirectional_traversal_tag for consistency -->
|
||||
</div>
|
||||
<div class="section" id="random-access-traversal-iterators-lib-random-access-traversal-iterators">
|
||||
<h4><a class="toc-backref" href="#id20" name="random-access-traversal-iterators-lib-random-access-traversal-iterators">Random Access Traversal Iterators [lib.random.access.traversal.iterators]</a></h4>
|
||||
<p>A class or built-in type <tt class="literal"><span class="pre">X</span></tt> models the <em>Random Access Traversal
|
||||
<p>A class or built-in type <tt class="docutils literal"><span class="pre">X</span></tt> models the <em>Random Access Traversal
|
||||
Iterator</em> concept if the following expressions are valid and respect
|
||||
the stated semantics. In the table below, <tt class="literal"><span class="pre">Distance</span></tt> is
|
||||
<tt class="literal"><span class="pre">iterator_traits<X>::difference_type</span></tt> and <tt class="literal"><span class="pre">n</span></tt> represents a
|
||||
constant object of type <tt class="literal"><span class="pre">Distance</span></tt>.</p>
|
||||
<table border="1" class="table">
|
||||
the stated semantics. In the table below, <tt class="docutils literal"><span class="pre">Distance</span></tt> is
|
||||
<tt class="docutils literal"><span class="pre">iterator_traits<X>::difference_type</span></tt> and <tt class="docutils literal"><span class="pre">n</span></tt> represents a
|
||||
constant object of type <tt class="docutils literal"><span class="pre">Distance</span></tt>.</p>
|
||||
<table border="1" class="docutils">
|
||||
<colgroup>
|
||||
<col width="28%" />
|
||||
<col width="30%" />
|
||||
@ -741,8 +741,8 @@ Precondition</th>
|
||||
</tr>
|
||||
</thead>
|
||||
<tbody valign="top">
|
||||
<tr><td><tt class="literal"><span class="pre">r</span> <span class="pre">+=</span> <span class="pre">n</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">X&</span></tt></td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">r</span> <span class="pre">+=</span> <span class="pre">n</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">X&</span></tt></td>
|
||||
<td><pre class="first last literal-block">
|
||||
{
|
||||
Distance m = n;
|
||||
@ -758,70 +758,70 @@ Precondition</th>
|
||||
</td>
|
||||
<td> </td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">a</span> <span class="pre">+</span> <span class="pre">n</span></tt>, <tt class="literal"><span class="pre">n</span> <span class="pre">+</span> <span class="pre">a</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">X</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">{</span> <span class="pre">X</span> <span class="pre">tmp</span> <span class="pre">=</span> <span class="pre">a;</span> <span class="pre">return</span> <span class="pre">tmp</span>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">a</span> <span class="pre">+</span> <span class="pre">n</span></tt>, <tt class="docutils literal"><span class="pre">n</span> <span class="pre">+</span> <span class="pre">a</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">X</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">{</span> <span class="pre">X</span> <span class="pre">tmp</span> <span class="pre">=</span> <span class="pre">a;</span> <span class="pre">return</span> <span class="pre">tmp</span>
|
||||
<span class="pre">+=</span> <span class="pre">n;</span> <span class="pre">}</span></tt></td>
|
||||
<td> </td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">r</span> <span class="pre">-=</span> <span class="pre">n</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">X&</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">return</span> <span class="pre">r</span> <span class="pre">+=</span> <span class="pre">-n</span></tt></td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">r</span> <span class="pre">-=</span> <span class="pre">n</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">X&</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">return</span> <span class="pre">r</span> <span class="pre">+=</span> <span class="pre">-n</span></tt></td>
|
||||
<td> </td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">a</span> <span class="pre">-</span> <span class="pre">n</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">X</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">{</span> <span class="pre">X</span> <span class="pre">tmp</span> <span class="pre">=</span> <span class="pre">a;</span> <span class="pre">return</span> <span class="pre">tmp</span>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">a</span> <span class="pre">-</span> <span class="pre">n</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">X</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">{</span> <span class="pre">X</span> <span class="pre">tmp</span> <span class="pre">=</span> <span class="pre">a;</span> <span class="pre">return</span> <span class="pre">tmp</span>
|
||||
<span class="pre">-=</span> <span class="pre">n;</span> <span class="pre">}</span></tt></td>
|
||||
<td> </td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">b</span> <span class="pre">-</span> <span class="pre">a</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">Distance</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">a</span> <span class="pre"><</span> <span class="pre">b</span> <span class="pre">?</span> <span class="pre">distance(a,b)</span>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">b</span> <span class="pre">-</span> <span class="pre">a</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">Distance</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">a</span> <span class="pre"><</span> <span class="pre">b</span> <span class="pre">?</span> <span class="pre">distance(a,b)</span>
|
||||
<span class="pre">:</span> <span class="pre">-distance(b,a)</span></tt></td>
|
||||
<td>pre: there exists a
|
||||
value <tt class="literal"><span class="pre">n</span></tt> of
|
||||
<tt class="literal"><span class="pre">Distance</span></tt> such that
|
||||
<tt class="literal"><span class="pre">a</span> <span class="pre">+</span> <span class="pre">n</span> <span class="pre">==</span> <span class="pre">b</span></tt>. <tt class="literal"><span class="pre">b</span>
|
||||
value <tt class="docutils literal"><span class="pre">n</span></tt> of
|
||||
<tt class="docutils literal"><span class="pre">Distance</span></tt> such that
|
||||
<tt class="docutils literal"><span class="pre">a</span> <span class="pre">+</span> <span class="pre">n</span> <span class="pre">==</span> <span class="pre">b</span></tt>. <tt class="docutils literal"><span class="pre">b</span>
|
||||
<span class="pre">==</span> <span class="pre">a</span> <span class="pre">+</span> <span class="pre">(b</span> <span class="pre">-</span> <span class="pre">a)</span></tt>.</td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">a[n]</span></tt></td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">a[n]</span></tt></td>
|
||||
<td>convertible to T</td>
|
||||
<td><tt class="literal"><span class="pre">*(a</span> <span class="pre">+</span> <span class="pre">n)</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">*(a</span> <span class="pre">+</span> <span class="pre">n)</span></tt></td>
|
||||
<td>pre: a is a <a class="reference" href="#readable-iterator">Readable
|
||||
Iterator</a></td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">a[n]</span> <span class="pre">=</span> <span class="pre">v</span></tt></td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">a[n]</span> <span class="pre">=</span> <span class="pre">v</span></tt></td>
|
||||
<td>convertible to T</td>
|
||||
<td><tt class="literal"><span class="pre">*(a</span> <span class="pre">+</span> <span class="pre">n)</span> <span class="pre">=</span> <span class="pre">v</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">*(a</span> <span class="pre">+</span> <span class="pre">n)</span> <span class="pre">=</span> <span class="pre">v</span></tt></td>
|
||||
<td>pre: a is a <a class="reference" href="#writable-iterator">Writable
|
||||
Iterator</a></td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">a</span> <span class="pre"><</span> <span class="pre">b</span></tt></td>
|
||||
<td>convertible to <tt class="literal"><span class="pre">bool</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">b</span> <span class="pre">-</span> <span class="pre">a</span> <span class="pre">></span> <span class="pre">0</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre"><</span></tt> is a total
|
||||
<tr><td><tt class="docutils literal"><span class="pre">a</span> <span class="pre"><</span> <span class="pre">b</span></tt></td>
|
||||
<td>convertible to <tt class="docutils literal"><span class="pre">bool</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">b</span> <span class="pre">-</span> <span class="pre">a</span> <span class="pre">></span> <span class="pre">0</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre"><</span></tt> is a total
|
||||
ordering relation</td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">a</span> <span class="pre">></span> <span class="pre">b</span></tt></td>
|
||||
<td>convertible to <tt class="literal"><span class="pre">bool</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">b</span> <span class="pre"><</span> <span class="pre">a</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">></span></tt> is a total
|
||||
<tr><td><tt class="docutils literal"><span class="pre">a</span> <span class="pre">></span> <span class="pre">b</span></tt></td>
|
||||
<td>convertible to <tt class="docutils literal"><span class="pre">bool</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">b</span> <span class="pre"><</span> <span class="pre">a</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">></span></tt> is a total
|
||||
ordering relation</td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">a</span> <span class="pre">>=</span> <span class="pre">b</span></tt></td>
|
||||
<td>convertible to <tt class="literal"><span class="pre">bool</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">!(a</span> <span class="pre"><</span> <span class="pre">b)</span></tt></td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">a</span> <span class="pre">>=</span> <span class="pre">b</span></tt></td>
|
||||
<td>convertible to <tt class="docutils literal"><span class="pre">bool</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">!(a</span> <span class="pre"><</span> <span class="pre">b)</span></tt></td>
|
||||
<td> </td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">a</span> <span class="pre"><=</span> <span class="pre">b</span></tt></td>
|
||||
<td>convertible to <tt class="literal"><span class="pre">bool</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">!(a</span> <span class="pre">></span> <span class="pre">b)</span></tt></td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">a</span> <span class="pre"><=</span> <span class="pre">b</span></tt></td>
|
||||
<td>convertible to <tt class="docutils literal"><span class="pre">bool</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">!(a</span> <span class="pre">></span> <span class="pre">b)</span></tt></td>
|
||||
<td> </td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">iterator_traversal<X>::type</span></tt></td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">iterator_traversal<X>::type</span></tt></td>
|
||||
<td>Convertible to
|
||||
<tt class="literal"><span class="pre">random_access_traversal_tag</span></tt></td>
|
||||
<tt class="docutils literal"><span class="pre">random_access_traversal_tag</span></tt></td>
|
||||
<td> </td>
|
||||
<td> </td>
|
||||
</tr>
|
||||
@ -832,14 +832,14 @@ random_access_traversal_tag for consistency -->
|
||||
</div>
|
||||
<div class="section" id="interoperable-iterators-lib-interoperable-iterators">
|
||||
<h4><a class="toc-backref" href="#id21" name="interoperable-iterators-lib-interoperable-iterators">Interoperable Iterators [lib.interoperable.iterators]</a></h4>
|
||||
<p>A class or built-in type <tt class="literal"><span class="pre">X</span></tt> that models Single Pass Iterator is
|
||||
<em>interoperable with</em> a class or built-in type <tt class="literal"><span class="pre">Y</span></tt> that also models
|
||||
<p>A class or built-in type <tt class="docutils literal"><span class="pre">X</span></tt> that models Single Pass Iterator is
|
||||
<em>interoperable with</em> a class or built-in type <tt class="docutils literal"><span class="pre">Y</span></tt> that also models
|
||||
Single Pass Iterator if the following expressions are valid and
|
||||
respect the stated semantics. In the tables below, <tt class="literal"><span class="pre">x</span></tt> is an object
|
||||
of type <tt class="literal"><span class="pre">X</span></tt>, <tt class="literal"><span class="pre">y</span></tt> is an object of type <tt class="literal"><span class="pre">Y</span></tt>, <tt class="literal"><span class="pre">Distance</span></tt> is
|
||||
<tt class="literal"><span class="pre">iterator_traits<Y>::difference_type</span></tt>, and <tt class="literal"><span class="pre">n</span></tt> represents a
|
||||
constant object of type <tt class="literal"><span class="pre">Distance</span></tt>.</p>
|
||||
<table border="1" class="table">
|
||||
respect the stated semantics. In the tables below, <tt class="docutils literal"><span class="pre">x</span></tt> is an object
|
||||
of type <tt class="docutils literal"><span class="pre">X</span></tt>, <tt class="docutils literal"><span class="pre">y</span></tt> is an object of type <tt class="docutils literal"><span class="pre">Y</span></tt>, <tt class="docutils literal"><span class="pre">Distance</span></tt> is
|
||||
<tt class="docutils literal"><span class="pre">iterator_traits<Y>::difference_type</span></tt>, and <tt class="docutils literal"><span class="pre">n</span></tt> represents a
|
||||
constant object of type <tt class="docutils literal"><span class="pre">Distance</span></tt>.</p>
|
||||
<table border="1" class="docutils">
|
||||
<colgroup>
|
||||
<col width="13%" />
|
||||
<col width="27%" />
|
||||
@ -852,35 +852,35 @@ constant object of type <tt class="literal"><span class="pre">Distance</span></t
|
||||
</tr>
|
||||
</thead>
|
||||
<tbody valign="top">
|
||||
<tr><td><tt class="literal"><span class="pre">y</span> <span class="pre">=</span> <span class="pre">x</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">Y</span></tt></td>
|
||||
<td>post: <tt class="literal"><span class="pre">y</span> <span class="pre">==</span> <span class="pre">x</span></tt></td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">y</span> <span class="pre">=</span> <span class="pre">x</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">Y</span></tt></td>
|
||||
<td>post: <tt class="docutils literal"><span class="pre">y</span> <span class="pre">==</span> <span class="pre">x</span></tt></td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">Y(x)</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">Y</span></tt></td>
|
||||
<td>post: <tt class="literal"><span class="pre">Y(x)</span> <span class="pre">==</span> <span class="pre">x</span></tt></td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">Y(x)</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">Y</span></tt></td>
|
||||
<td>post: <tt class="docutils literal"><span class="pre">Y(x)</span> <span class="pre">==</span> <span class="pre">x</span></tt></td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">x</span> <span class="pre">==</span> <span class="pre">y</span></tt></td>
|
||||
<td>convertible to <tt class="literal"><span class="pre">bool</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">==</span></tt> is an equivalence relation over its domain.</td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">x</span> <span class="pre">==</span> <span class="pre">y</span></tt></td>
|
||||
<td>convertible to <tt class="docutils literal"><span class="pre">bool</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">==</span></tt> is an equivalence relation over its domain.</td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">y</span> <span class="pre">==</span> <span class="pre">x</span></tt></td>
|
||||
<td>convertible to <tt class="literal"><span class="pre">bool</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">==</span></tt> is an equivalence relation over its domain.</td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">y</span> <span class="pre">==</span> <span class="pre">x</span></tt></td>
|
||||
<td>convertible to <tt class="docutils literal"><span class="pre">bool</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">==</span></tt> is an equivalence relation over its domain.</td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">x</span> <span class="pre">!=</span> <span class="pre">y</span></tt></td>
|
||||
<td>convertible to <tt class="literal"><span class="pre">bool</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">bool(a==b)</span> <span class="pre">!=</span> <span class="pre">bool(a!=b)</span></tt> over its domain.</td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">x</span> <span class="pre">!=</span> <span class="pre">y</span></tt></td>
|
||||
<td>convertible to <tt class="docutils literal"><span class="pre">bool</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">bool(a==b)</span> <span class="pre">!=</span> <span class="pre">bool(a!=b)</span></tt> over its domain.</td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">y</span> <span class="pre">!=</span> <span class="pre">x</span></tt></td>
|
||||
<td>convertible to <tt class="literal"><span class="pre">bool</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">bool(a==b)</span> <span class="pre">!=</span> <span class="pre">bool(a!=b)</span></tt> over its domain.</td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">y</span> <span class="pre">!=</span> <span class="pre">x</span></tt></td>
|
||||
<td>convertible to <tt class="docutils literal"><span class="pre">bool</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">bool(a==b)</span> <span class="pre">!=</span> <span class="pre">bool(a!=b)</span></tt> over its domain.</td>
|
||||
</tr>
|
||||
</tbody>
|
||||
</table>
|
||||
<p>If <tt class="literal"><span class="pre">X</span></tt> and <tt class="literal"><span class="pre">Y</span></tt> both model Random Access Traversal Iterator then
|
||||
<p>If <tt class="docutils literal"><span class="pre">X</span></tt> and <tt class="docutils literal"><span class="pre">Y</span></tt> both model Random Access Traversal Iterator then
|
||||
the following additional requirements must be met.</p>
|
||||
<table border="1" class="table">
|
||||
<table border="1" class="docutils">
|
||||
<colgroup>
|
||||
<col width="12%" />
|
||||
<col width="25%" />
|
||||
@ -895,59 +895,59 @@ the following additional requirements must be met.</p>
|
||||
</tr>
|
||||
</thead>
|
||||
<tbody valign="top">
|
||||
<tr><td><tt class="literal"><span class="pre">x</span> <span class="pre"><</span> <span class="pre">y</span></tt></td>
|
||||
<td>convertible to <tt class="literal"><span class="pre">bool</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">y</span> <span class="pre">-</span> <span class="pre">x</span> <span class="pre">></span> <span class="pre">0</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre"><</span></tt> is a total ordering relation</td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">x</span> <span class="pre"><</span> <span class="pre">y</span></tt></td>
|
||||
<td>convertible to <tt class="docutils literal"><span class="pre">bool</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">y</span> <span class="pre">-</span> <span class="pre">x</span> <span class="pre">></span> <span class="pre">0</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre"><</span></tt> is a total ordering relation</td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">y</span> <span class="pre"><</span> <span class="pre">x</span></tt></td>
|
||||
<td>convertible to <tt class="literal"><span class="pre">bool</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">x</span> <span class="pre">-</span> <span class="pre">y</span> <span class="pre">></span> <span class="pre">0</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre"><</span></tt> is a total ordering relation</td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">y</span> <span class="pre"><</span> <span class="pre">x</span></tt></td>
|
||||
<td>convertible to <tt class="docutils literal"><span class="pre">bool</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">x</span> <span class="pre">-</span> <span class="pre">y</span> <span class="pre">></span> <span class="pre">0</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre"><</span></tt> is a total ordering relation</td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">x</span> <span class="pre">></span> <span class="pre">y</span></tt></td>
|
||||
<td>convertible to <tt class="literal"><span class="pre">bool</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">y</span> <span class="pre"><</span> <span class="pre">x</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">></span></tt> is a total ordering relation</td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">x</span> <span class="pre">></span> <span class="pre">y</span></tt></td>
|
||||
<td>convertible to <tt class="docutils literal"><span class="pre">bool</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">y</span> <span class="pre"><</span> <span class="pre">x</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">></span></tt> is a total ordering relation</td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">y</span> <span class="pre">></span> <span class="pre">x</span></tt></td>
|
||||
<td>convertible to <tt class="literal"><span class="pre">bool</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">x</span> <span class="pre"><</span> <span class="pre">y</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">></span></tt> is a total ordering relation</td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">y</span> <span class="pre">></span> <span class="pre">x</span></tt></td>
|
||||
<td>convertible to <tt class="docutils literal"><span class="pre">bool</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">x</span> <span class="pre"><</span> <span class="pre">y</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">></span></tt> is a total ordering relation</td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">x</span> <span class="pre">>=</span> <span class="pre">y</span></tt></td>
|
||||
<td>convertible to <tt class="literal"><span class="pre">bool</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">!(x</span> <span class="pre"><</span> <span class="pre">y)</span></tt></td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">x</span> <span class="pre">>=</span> <span class="pre">y</span></tt></td>
|
||||
<td>convertible to <tt class="docutils literal"><span class="pre">bool</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">!(x</span> <span class="pre"><</span> <span class="pre">y)</span></tt></td>
|
||||
<td> </td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">y</span> <span class="pre">>=</span> <span class="pre">x</span></tt></td>
|
||||
<td>convertible to <tt class="literal"><span class="pre">bool</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">!(y</span> <span class="pre"><</span> <span class="pre">x)</span></tt></td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">y</span> <span class="pre">>=</span> <span class="pre">x</span></tt></td>
|
||||
<td>convertible to <tt class="docutils literal"><span class="pre">bool</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">!(y</span> <span class="pre"><</span> <span class="pre">x)</span></tt></td>
|
||||
<td> </td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">x</span> <span class="pre"><=</span> <span class="pre">y</span></tt></td>
|
||||
<td>convertible to <tt class="literal"><span class="pre">bool</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">!(x</span> <span class="pre">></span> <span class="pre">y)</span></tt></td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">x</span> <span class="pre"><=</span> <span class="pre">y</span></tt></td>
|
||||
<td>convertible to <tt class="docutils literal"><span class="pre">bool</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">!(x</span> <span class="pre">></span> <span class="pre">y)</span></tt></td>
|
||||
<td> </td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">y</span> <span class="pre"><=</span> <span class="pre">x</span></tt></td>
|
||||
<td>convertible to <tt class="literal"><span class="pre">bool</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">!(y</span> <span class="pre">></span> <span class="pre">x)</span></tt></td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">y</span> <span class="pre"><=</span> <span class="pre">x</span></tt></td>
|
||||
<td>convertible to <tt class="docutils literal"><span class="pre">bool</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">!(y</span> <span class="pre">></span> <span class="pre">x)</span></tt></td>
|
||||
<td> </td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">y</span> <span class="pre">-</span> <span class="pre">x</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">Distance</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">distance(Y(x),y)</span></tt></td>
|
||||
<td>pre: there exists a value <tt class="literal"><span class="pre">n</span></tt> of
|
||||
<tt class="literal"><span class="pre">Distance</span></tt> such that <tt class="literal"><span class="pre">x</span> <span class="pre">+</span> <span class="pre">n</span> <span class="pre">==</span> <span class="pre">y</span></tt>.
|
||||
<tt class="literal"><span class="pre">y</span> <span class="pre">==</span> <span class="pre">x</span> <span class="pre">+</span> <span class="pre">(y</span> <span class="pre">-</span> <span class="pre">x)</span></tt>.</td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">y</span> <span class="pre">-</span> <span class="pre">x</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">Distance</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">distance(Y(x),y)</span></tt></td>
|
||||
<td>pre: there exists a value <tt class="docutils literal"><span class="pre">n</span></tt> of
|
||||
<tt class="docutils literal"><span class="pre">Distance</span></tt> such that <tt class="docutils literal"><span class="pre">x</span> <span class="pre">+</span> <span class="pre">n</span> <span class="pre">==</span> <span class="pre">y</span></tt>.
|
||||
<tt class="docutils literal"><span class="pre">y</span> <span class="pre">==</span> <span class="pre">x</span> <span class="pre">+</span> <span class="pre">(y</span> <span class="pre">-</span> <span class="pre">x)</span></tt>.</td>
|
||||
</tr>
|
||||
<tr><td><tt class="literal"><span class="pre">x</span> <span class="pre">-</span> <span class="pre">y</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">Distance</span></tt></td>
|
||||
<td><tt class="literal"><span class="pre">distance(y,Y(x))</span></tt></td>
|
||||
<td>pre: there exists a value <tt class="literal"><span class="pre">n</span></tt> of
|
||||
<tt class="literal"><span class="pre">Distance</span></tt> such that <tt class="literal"><span class="pre">y</span> <span class="pre">+</span> <span class="pre">n</span> <span class="pre">==</span> <span class="pre">x</span></tt>.
|
||||
<tt class="literal"><span class="pre">x</span> <span class="pre">==</span> <span class="pre">y</span> <span class="pre">+</span> <span class="pre">(x</span> <span class="pre">-</span> <span class="pre">y)</span></tt>.</td>
|
||||
<tr><td><tt class="docutils literal"><span class="pre">x</span> <span class="pre">-</span> <span class="pre">y</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">Distance</span></tt></td>
|
||||
<td><tt class="docutils literal"><span class="pre">distance(y,Y(x))</span></tt></td>
|
||||
<td>pre: there exists a value <tt class="docutils literal"><span class="pre">n</span></tt> of
|
||||
<tt class="docutils literal"><span class="pre">Distance</span></tt> such that <tt class="docutils literal"><span class="pre">y</span> <span class="pre">+</span> <span class="pre">n</span> <span class="pre">==</span> <span class="pre">x</span></tt>.
|
||||
<tt class="docutils literal"><span class="pre">x</span> <span class="pre">==</span> <span class="pre">y</span> <span class="pre">+</span> <span class="pre">(x</span> <span class="pre">-</span> <span class="pre">y)</span></tt>.</td>
|
||||
</tr>
|
||||
</tbody>
|
||||
</table>
|
||||
@ -970,13 +970,13 @@ struct random_access_traversal_tag : bidirectional_traversal_tag { };
|
||||
</div>
|
||||
<div class="section" id="addition-to-lib-iterator-traits">
|
||||
<h2><a class="toc-backref" href="#id23" name="addition-to-lib-iterator-traits">Addition to [lib.iterator.traits]</a></h2>
|
||||
<p>The <tt class="literal"><span class="pre">is_readable_iterator</span></tt> class
|
||||
<p>The <tt class="docutils literal"><span class="pre">is_readable_iterator</span></tt> class
|
||||
template satisfies the <a class="reference" href="http://anubis.dkuug.dk/jtc1/sc22/wg21/docs/papers/2003/n1519.htm">UnaryTypeTrait</a> requirements.</p>
|
||||
<p>Given an iterator type <tt class="literal"><span class="pre">X</span></tt>, <tt class="literal"><span class="pre">is_readable_iterator<X>::value</span></tt>
|
||||
yields <tt class="literal"><span class="pre">true</span></tt> if, for an object <tt class="literal"><span class="pre">a</span></tt> of type <tt class="literal"><span class="pre">X</span></tt>, <tt class="literal"><span class="pre">*a</span></tt> is
|
||||
convertible to <tt class="literal"><span class="pre">iterator_traits<X>::value_type</span></tt>, and <tt class="literal"><span class="pre">false</span></tt>
|
||||
<p>Given an iterator type <tt class="docutils literal"><span class="pre">X</span></tt>, <tt class="docutils literal"><span class="pre">is_readable_iterator<X>::value</span></tt>
|
||||
yields <tt class="docutils literal"><span class="pre">true</span></tt> if, for an object <tt class="docutils literal"><span class="pre">a</span></tt> of type <tt class="docutils literal"><span class="pre">X</span></tt>, <tt class="docutils literal"><span class="pre">*a</span></tt> is
|
||||
convertible to <tt class="docutils literal"><span class="pre">iterator_traits<X>::value_type</span></tt>, and <tt class="docutils literal"><span class="pre">false</span></tt>
|
||||
otherwise.</p>
|
||||
<p><tt class="literal"><span class="pre">iterator_traversal<X>::type</span></tt> is</p>
|
||||
<p><tt class="docutils literal"><span class="pre">iterator_traversal<X>::type</span></tt> is</p>
|
||||
<pre class="literal-block">
|
||||
<em>category-to-traversal</em>(iterator_traits<X>::iterator_category)
|
||||
</pre>
|
||||
@ -1004,7 +1004,7 @@ otherwise.</p>
|
||||
<h1><a class="toc-backref" href="#id24" name="footnotes">Footnotes</a></h1>
|
||||
<p>The UnaryTypeTrait concept is defined in <a class="reference" href="http://anubis.dkuug.dk/jtc1/sc22/wg21/docs/papers/2003/n1519.htm">n1519</a>; the LWG is
|
||||
considering adding the requirement that specializations are derived
|
||||
from their nested <tt class="literal"><span class="pre">::type</span></tt>.</p>
|
||||
from their nested <tt class="docutils literal"><span class="pre">::type</span></tt>.</p>
|
||||
<!-- LocalWords: Abrahams Siek Witt const bool Sutter's WG int UL LI href Lvalue
|
||||
LocalWords: ReadableIterator WritableIterator SwappableIterator cv pre iter
|
||||
LocalWords: ConstantLvalueIterator MutableLvalueIterator CopyConstructible TR
|
||||
@ -1014,7 +1014,7 @@ LocalWords: incrementable xxx min prev inplace png oldeqnew AccessTag struct
|
||||
LocalWords: TraversalTag typename lvalues DWA Hmm JGS mis enum -->
|
||||
</div>
|
||||
</div>
|
||||
<hr class="footer" />
|
||||
<hr class="docutils footer" />
|
||||
<div class="footer">
|
||||
<a class="reference" href="new-iter-concepts.rst">View document source</a>.
|
||||
Generated by <a class="reference" href="http://docutils.sourceforge.net/">Docutils</a> from <a class="reference" href="http://docutils.sourceforge.net/rst.html">reStructuredText</a> source.
|
||||
|
||||
Reference in New Issue
Block a user