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changed named parameters doc to match new stuff

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[SVN r11417]
This commit is contained in:
Jeremy Siek
2001-10-22 17:04:23 +00:00
parent 139e33c36d
commit 354aef0e8c
1 changed files with 25 additions and 54 deletions
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79
iterator_adaptors.htm
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@@ -131,11 +131,11 @@
<p><tt>iterator_adaptor</tt> is declared like this:
<pre>
template &lt;class Base, class Policies,
class ValueOrNamedParams = typename std::iterator_traits&lt;Base&gt;::value_type,
class ReferenceOrNamedParams = <i>...(see below)</i>,
class PointerOrNamedParams = <i>...(see below)</i>,
class CategoryOrNamedParams = typename std::iterator_traits&lt;Base&gt;::iterator_category,
class DistanceOrNamedParams = typename std::iterator_traits&lt;Base&gt;::difference_type&gt;
class ValueOrNamedParam = typename std::iterator_traits&lt;Base&gt;::value_type,
class ReferenceOrNamedParam = <i>...(see below)</i>,
class PointerOrNamedParam = <i>...(see below)</i>,
class CategoryOrNamedParam = typename std::iterator_traits&lt;Base&gt;::iterator_category,
class DistanceOrNamedParam = typename std::iterator_traits&lt;Base&gt;::difference_type&gt;
struct iterator_adaptor;
</pre>
@@ -208,11 +208,9 @@ struct iterator_adaptor;
<tt>std::iterator_traits&lt;BaseType&gt;::difference_type</tt>
<tr>
<td><tt>NamedParams</tt>
<td><tt>NamedParam</tt>
<td>A list of named template parameters generated using the
<a href="#iterator_traits_generator">
<tt>iterator_traits_generator</tt></a> class (see below).
<td>A named template parameter (see below).
</table>
<h3><a name="named_template_parameters">Named Template Parameters</a></h3>
@@ -223,59 +221,32 @@ struct iterator_adaptor;
template parameter, but use the defaults for the third through
fifth. As a solution to these problems we provide a mechanism for
naming the last five template parameters, and providing them in
any order through the <tt>iterator_traits_generator</tt> class.
any order through a set of named template parameters. The following
classes are provided for specifying the parameters. Any of these
classes can be used for any of the last five template parameters
of <tt>iterator_adaptor</tt>.
<blockquote>
<pre>
<a name="iterator_traits_generator">class iterator_traits_generator</a>
{
public:
template &lt;class Value&gt;
struct value_type : public <i>recursive magic</i> { };
template &lt;class Reference&gt;
struct reference : public <i>recursive magic</i> { };
template &lt;class Pointer&gt;
struct pointer : public <i>recursive magic</i> { };
template &lt;class Distance&gt;
struct difference_type : public <i>recursive magic</i> { };
template &lt;class Category&gt;
struct iterator_category : public <i>recursive magic</i> { };
};
template &lt;class Value&gt; struct value_type_is;
template &lt;class Reference&gt; struct reference_is;
template &lt;class Pointer&gt; struct pointer_is;
template &lt;class Distance&gt; struct difference_type_is;
template &lt;class Category&gt; struct iterator_category_is;
</pre>
</blockquote>
The <tt>iterator_traits_generator</tt> is used to create a list of
of template arguments. For example, suppose you want to set the
<tt>Reference</tt> and <tt>Category</tt> parameters, and use the
defaults for the rest. Then you can use the traits generator as
follows:
For example, the following adapts <tt>foo_iterator</tt> to create
an <a href=
"http://www.sgi.com/tech/stl/InputIterator.html">InputIterator</a>
with <tt>reference</tt> type <tt>foo</tt>, and whose other traits
are determined according to the defaults described <a
href="#template_parameters">above</a>.
<blockquote>
<pre>
iterator_traits_generator::reference&lt;foo&gt;::category&lt;std::input_iterator_tag&gt;
</pre>
</blockquote>
This generated type can then be passed into the <tt>iterator_adaptor</tt>
class to replace any of the last five parameters. If you use the traits
generator in the <i>i</i>th parameter position, then the parameters <i>i</i>
through 7 will use the types specified in the generator. For example, the
following adapts <tt>foo_iterator</tt> to create an <a href=
"http://www.sgi.com/tech/stl/InputIterator.html">InputIterator</a> with
<tt>reference</tt> type <tt>foo</tt>, and whose other traits are determined
according to the defaults described <a href="#template_parameters">above</a>.
<blockquote>
<pre>
iterator_adaptor&lt;foo_iterator, foo_policies,
iterator_traits_generator
::reference&lt;foo&gt;
::iterator_category&lt;std::input_iterator_tag&gt;
&gt;
typedef iterator_adaptor&lt;foo_iterator, foo_policies,
reference_is&lt;foo&gt;, iterator_category_is&lt;std::input_iterator_tag&gt;
&gt; MyIterator;
</pre>
</blockquote>