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iterator/doc/indirect_iterator_ref.html
Jeremy Siek 506517191c new files for iterator concepts 
[SVN r22004]
2004-01-27 17:03:46 +00:00

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<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta name="generator" content="Docutils 0.2.8: http://docutils.sourceforge.net/" />
<link rel="stylesheet" href="default.css" type="text/css" />
</head>
<body>
<div class="document">
<pre class="literal-block">
template &lt;
class Iterator
, class Value = use_default
, class CategoryOrTraversal = use_default
, class Reference = use_default
, class Difference = use_default
&gt;
class indirect_iterator
{
public:
typedef /* see below */ value_type;
typedef /* see below */ reference;
typedef /* see below */ pointer;
typedef /* see below */ difference_type;
typedef /* see below */ iterator_category;
indirect_iterator();
indirect_iterator(Iterator x);
template &lt;
class Iterator2, class Value2, class Category2
, class Reference2, class Difference2
&gt;
indirect_iterator(
indirect_iterator&lt;
Iterator2, Value2, Category2, Reference2, Difference2
&gt; const&amp; y
, typename enable_if_convertible&lt;Iterator2, Iterator&gt;::type* = 0 // exposition
);
};
</pre>
<p>The member types of <tt class="literal"><span class="pre">indirect_iterator</span></tt> are defined according to the
following pseudo-code. We use the abbreviation
<tt class="literal"><span class="pre">V=iterator_traits&lt;Iterator&gt;::value_type</span></tt> and <tt class="literal"><span class="pre">v</span></tt> is an object of
type <tt class="literal"><span class="pre">V</span></tt>.:</p>
<pre class="literal-block">
if (Value is use_default) then
typedef iterator_traits&lt;V&gt;::value_type value_type;
else
typedef remove_const&lt;Value&gt;::type value_type;
if (Reference is use_default) then
typedef iterator_traits&lt;V&gt;::reference reference;
else
typedef Reference reference;
typedef Value* pointer;
if (Difference is use_default)
typedef iterator_traits&lt;Iterator&gt;::difference_type difference_type;
else
typedef Difference difference_type;
</pre>
<p>The member <tt class="literal"><span class="pre">indirect_iterator::iterator_category</span></tt> is a type that
satisfies the requirements of the concepts modeled by the indirect
iterator as specified in the models section.</p>
<div class="section" id="indirect-iterator-requirements">
<h1><a name="indirect-iterator-requirements"><tt class="literal"><span class="pre">indirect_iterator</span></tt> requirements</a></h1>
<p>The <tt class="literal"><span class="pre">Iterator</span></tt> argument shall meet the requirements of Readable
Iterator. The <tt class="literal"><span class="pre">CategoryOrTraversal</span></tt> argument shall be one of the
standard iterator tags or <tt class="literal"><span class="pre">use_default</span></tt>. If <tt class="literal"><span class="pre">CategoryOrTraversal</span></tt>
is an iterator tag, the template parameter <tt class="literal"><span class="pre">Iterator</span></tt> argument shall
meet the traversal requirements corresponding to the iterator tag.</p>
<p>The expression <tt class="literal"><span class="pre">*v</span></tt>, where <tt class="literal"><span class="pre">v</span></tt> is an object of type
<tt class="literal"><span class="pre">iterator_traits&lt;Iterator&gt;::value_type</span></tt>, must be a valid expression
and must be convertible to <tt class="literal"><span class="pre">indirect_iterator::reference</span></tt>. Also,
there are further requirements on the
<tt class="literal"><span class="pre">iterator_traits&lt;Iterator&gt;::value_type</span></tt> if the <tt class="literal"><span class="pre">Value</span></tt> parameter
is not <tt class="literal"><span class="pre">use_default</span></tt>, as implied by the algorithm for deducing the
default for the <tt class="literal"><span class="pre">value_type</span></tt> member.</p>
</div>
<div class="section" id="indirect-iterator-models">
<h1><a name="indirect-iterator-models"><tt class="literal"><span class="pre">indirect_iterator</span></tt> models</a></h1>
<p>If <tt class="literal"><span class="pre">CategoryOrTraversal</span></tt> is a standard iterator tag,
<tt class="literal"><span class="pre">indirect_iterator</span></tt> is a model of the iterator concept corresponding
to the tag, otherwise <tt class="literal"><span class="pre">indirect_iterator</span></tt> satisfies the requirements
of the most refined standard traversal concept that is satisfied by
the <tt class="literal"><span class="pre">Iterator</span></tt> argument.</p>
<p><tt class="literal"><span class="pre">indirect_iterator</span></tt> models Readable Iterator. If
<tt class="literal"><span class="pre">indirect_iterator::reference(*v)</span> <span class="pre">=</span> <span class="pre">t</span></tt> is a valid expression (where
<tt class="literal"><span class="pre">t</span></tt> is an object of type <tt class="literal"><span class="pre">indirect_iterator::value_type</span></tt>) then
<tt class="literal"><span class="pre">indirect_iterator</span></tt> models Writable Iterator. If
<tt class="literal"><span class="pre">indirect_iterator::reference</span></tt> is a reference then
<tt class="literal"><span class="pre">indirect_iterator</span></tt> models Lvalue Iterator.</p>
</div>
<div class="section" id="indirect-iterator-operations">
<h1><a name="indirect-iterator-operations"><tt class="literal"><span class="pre">indirect_iterator</span></tt> operations</a></h1>
<p><tt class="literal"><span class="pre">indirect_iterator();</span></tt></p>
<table class="field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Requires:</th><td class="field-body"><tt class="literal"><span class="pre">Iterator</span></tt> must be Default Constructible.</td>
</tr>
<tr class="field"><th class="field-name">Returns:</th><td class="field-body">An instance of <tt class="literal"><span class="pre">indirect_iterator</span></tt> with
a default-constructed <tt class="literal"><span class="pre">iterator_adaptor</span></tt> subobject.</td>
</tr>
</tbody>
</table>
<p><tt class="literal"><span class="pre">indirect_iterator(Iterator</span> <span class="pre">x);</span></tt></p>
<table class="field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Returns:</th><td class="field-body">An instance of <tt class="literal"><span class="pre">indirect_iterator</span></tt> with
the <tt class="literal"><span class="pre">iterator_adaptor</span></tt> subobject copy constructed from <tt class="literal"><span class="pre">x</span></tt>.</td>
</tr>
</tbody>
</table>
<pre class="literal-block">
template &lt;
class Iterator2, class Value2, unsigned Access, class Traversal
, class Reference2, class Difference2
&gt;
indirect_iterator(
indirect_iterator&lt;
Iterator2, Value2, Access, Traversal, Reference2, Difference2
&gt; const&amp; y
, typename enable_if_convertible&lt;Iterator2, Iterator&gt;::type* = 0 // exposition
);
</pre>
<table class="field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Requires:</th><td class="field-body"><tt class="literal"><span class="pre">Iterator2</span></tt> is implicitly convertible to <tt class="literal"><span class="pre">Iterator</span></tt>.</td>
</tr>
<tr class="field"><th class="field-name">Returns:</th><td class="field-body">An instance of <tt class="literal"><span class="pre">indirect_iterator</span></tt> whose
<tt class="literal"><span class="pre">iterator_adaptor</span></tt> subobject is constructed from <tt class="literal"><span class="pre">y.base()</span></tt>.</td>
</tr>
</tbody>
</table>
</div>
</div>
</body>
</html>
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