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+<?xml version="1.0"?>
+<concept name="ForwardIterator" category="Iterator"><!--
+Based on concepts from the SGI Standard Template Library documentation:
+Copyright (c) 1996-1999
+Silicon Graphics Computer Systems, Inc.
+
+Copyright (c) 1994
+Hewlett-Packard Company
+--><!--
+Copyright 2000-2001 University of Notre Dame du Lac.
+Copyright 2001-2002 Indiana University.
+Some concepts based on versions from the MTL draft manual and Boost Graph
+and Property Map documentation:
+Copyright (c) Jeremy Siek, Lie-Quan Lee, and Andrew Lumsdaine 2000
+-->
+ <param name="Iter" role="iterator-type"/>
+
+ <use-header name="iterator"/>
+
+ <models-sentence>The iterator type <arg num="1"/> must be a model of <self/>.</models-sentence>
+
+ <description>
+ <para>A forward iterator is an iterator that can read through a sequence of
+ values. It is multi-pass (old values of the iterator can be
+ re-used), and can be either mutable (data pointed to by it can be
+ changed) or not mutable.</para>
+
+ <para>An iterator represents a position in a sequence. Therefore, the
+ iterator can point into the sequence (returning a value when dereferenced
+ and being incrementable), or be off-the-end (and not dereferenceable or
+ incrementable).</para>
+ </description>
+
+ <associated-type name="value_type">
+ <get-member-type name="value_type">
+ <apply-template name="std::iterator_traits">
+ <type name="Iter"/>
+ </apply-template>
+ </get-member-type>
+ <description><simpara>The value type of the iterator</simpara></description>
+ </associated-type>
+
+ <refines const="no" concept="InputIterator"/>
+ <refines const="no" concept="OutputIterator"/>
+
+<!-- DPG doesn't understand this
+ <models const="no" testable="yes" concept="Input Iterator">
+ <type name="Iter"/>
+ </models>
+-->
+<!--
+ <models-when-mutable concept="Output Iterator">
+ <type name="Iter"/>
+ <type name="value_type"/>
+ </models-when-mutable>
+-->
+
+ <notation variables="i j">
+ <sample-value>
+ <type name="Iter"/>
+ </sample-value>
+ </notation>
+
+ <associated-type name="category">
+ <get-member-type name="iterator_category">
+ <apply-template name="std::iterator_traits">
+ <type name="Iter"/>
+ </apply-template>
+ </get-member-type>
+ <description><simpara>The category of the iterator</simpara></description>
+ </associated-type>
+
+ <notation variables="x">
+ <sample-value>
+ <type name="value_type"/>
+ </sample-value>
+ </notation>
+
+ <valid-type-expression name="Category tag">
+ <description/>
+ <type name="category"/>
+ <return-type>
+ <derived-from testable="yes">
+ <type name="std::forward_iterator_tag"/>
+ </derived-from>
+ </return-type>
+ </valid-type-expression>
+
+ <valid-expression name="Dereference">
+ <dereference>
+ <sample-value><type name="Iter"/></sample-value>
+ </dereference>
+ <return-type>
+ <require-same-type testable="yes">
+ <const-if-not-mutable>
+ <reference-to><type name="value_type"/></reference-to>
+ </const-if-not-mutable>
+ </require-same-type>
+ </return-type>
+ <precondition><code>i</code> is incrementable (not
+ off-the-end)</precondition>
+ </valid-expression>
+
+ <valid-expression name="Member access">
+ <pointer-member>
+ <sample-value><type name="Iter"/></sample-value>
+ </pointer-member>
+ <return-type>
+ <require-same-type testable="yes">
+ <const-if-not-mutable>
+ <pointer-to><type name="value_type"/></pointer-to>
+ </const-if-not-mutable>
+ </require-same-type>
+ </return-type>
+ <precondition><code>i</code> is incrementable (not
+ off-the-end)</precondition>
+ </valid-expression>
+
+ <valid-expression name="Preincrement">
+ <preincrement>
+ <sample-value><reference-to><type name="Iter"/></reference-to></sample-value>
+ </preincrement>
+ <return-type>
+ <require-same-type testable="yes">
+ <reference-to><type name="Iter"/></reference-to>
+ </require-same-type>
+ </return-type>
+ <precondition><code>i</code> is incrementable (not
+ off-the-end)</precondition>
+ </valid-expression>
+
+ <valid-expression name="Postincrement">
+ <postincrement>
+ <sample-value><reference-to><type name="Iter"/></reference-to></sample-value>
+ </postincrement>
+ <return-type>
+ <require-same-type testable="yes"><type name="Iter"/></require-same-type>
+ </return-type>
+ <precondition><code>i</code> is incrementable (not
+ off-the-end)</precondition>
+ <semantics>Equivalent to <code>{Iter j = i; ++i; return j;}</code></semantics>
+ <postcondition><code>i</code> is dereferenceable or
+ off-the-end</postcondition>
+ </valid-expression>
+
+ <complexity>
+ All iterator operations must take amortized constant time.
+ </complexity>
+
+ <invariant name="Predecrement must return object">
+ <code>&i = &(++i)</code>
+ </invariant>
+
+ <invariant name="Unique path through sequence">
+ <code>i == j</code> implies <code>++i == ++j</code>
+ </invariant>
+
+ <example-model>
+ <pointer-to>
+ <type name="T"/>
+ </pointer-to>
+ </example-model>
+
+ <example-model>
+ <get-member-type name="iterator">
+ <apply-template name="std::hash_set">
+ <type name="T"/>
+ </apply-template>
+ </get-member-type>
+ </example-model>
+
+ <see-also concept="BidirectionalIterator"/>
+
+</concept>