| <?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> |