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<div class="titlepage"><div><div><h4 class="title">
<a name="fusion.sequence.concepts.forward_sequence"></a><a class="link" href="forward_sequence.html" title="Forward Sequence">Forward
Sequence</a>
</h4></div></div></div>
<a name="fusion.sequence.concepts.forward_sequence.description"></a><h6>
<a name="id910842"></a>
<a class="link" href="forward_sequence.html#fusion.sequence.concepts.forward_sequence.description">Description</a>
</h6>
<p>
A Forward Sequence is a Sequence whose elements are arranged in a definite
order. The ordering is guaranteed not to change from iteration to iteration.
The requirement of a definite ordering allows the definition of element-by-element
equality (if the container's element type is Equality Comparable) and of
lexicographical ordering (if the container's element type is LessThan Comparable).
</p>
<div class="variablelist">
<p class="title"><b>Notation</b></p>
<dl>
<dt><span class="term"><code class="computeroutput"><span class="identifier">s</span></code></span></dt>
<dd><p>
A Forward Sequence
</p></dd>
<dt><span class="term"><code class="computeroutput"><span class="identifier">S</span></code></span></dt>
<dd><p>
A Forward Sequence type
</p></dd>
<dt><span class="term"><code class="computeroutput"><span class="identifier">o</span></code></span></dt>
<dd><p>
An arbitrary object
</p></dd>
<dt><span class="term"><code class="computeroutput"><span class="identifier">e</span></code></span></dt>
<dd><p>
A Sequence element
</p></dd>
</dl>
</div>
<a name="fusion.sequence.concepts.forward_sequence.valid_expressions"></a><h6>
<a name="id910945"></a>
<a class="link" href="forward_sequence.html#fusion.sequence.concepts.forward_sequence.valid_expressions">Valid
Expressions</a>
</h6>
<p>
For any Forward Sequence the following expressions must be valid:
</p>
<div class="informaltable"><table class="table">
<colgroup>
<col>
<col>
<col>
<col>
</colgroup>
<thead><tr>
<th>
<p>
Expression
</p>
</th>
<th>
<p>
Return type
</p>
</th>
<th>
<p>
Type Requirements
</p>
</th>
<th>
<p>
Runtime Complexity
</p>
</th>
</tr></thead>
<tbody>
<tr>
<td>
<p>
<code class="computeroutput"><a class="link" href="../intrinsic/functions/begin.html" title="begin"><code class="computeroutput"><span class="identifier">begin</span></code></a><span class="special">(</span><span class="identifier">s</span><span class="special">)</span></code>
</p>
</td>
<td>
<p>
<a class="link" href="../../iterator/concepts/forward_iterator.html" title="Forward Iterator">Forward
Iterator</a>
</p>
</td>
<td>
</td>
<td>
<p>
Constant
</p>
</td>
</tr>
<tr>
<td>
<p>
<code class="computeroutput"><a class="link" href="../intrinsic/functions/end.html" title="end"><code class="computeroutput"><span class="identifier">end</span></code></a><span class="special">(</span><span class="identifier">s</span><span class="special">)</span></code>
</p>
</td>
<td>
<p>
<a class="link" href="../../iterator/concepts/forward_iterator.html" title="Forward Iterator">Forward
Iterator</a>
</p>
</td>
<td>
</td>
<td>
<p>
Constant
</p>
</td>
</tr>
<tr>
<td>
<p>
<code class="computeroutput"><a class="link" href="../intrinsic/functions/size.html" title="size"><code class="computeroutput"><span class="identifier">size</span></code></a><span class="special">(</span><span class="identifier">s</span><span class="special">)</span></code>
</p>
</td>
<td>
<p>
<a href="http://www.boost.org/libs/mpl/doc/refmanual/integral-constant.html" target="_top">MPL
Integral Constant</a>. Convertible to int.
</p>
</td>
<td>
</td>
<td>
<p>
Constant
</p>
</td>
</tr>
<tr>
<td>
<p>
<code class="computeroutput"><a class="link" href="../intrinsic/functions/empty.html" title="empty"><code class="computeroutput"><span class="identifier">empty</span></code></a><span class="special">(</span><span class="identifier">s</span><span class="special">)</span></code>
</p>
</td>
<td>
<p>
<a href="http://www.boost.org/libs/mpl/doc/refmanual/integral-constant.html" target="_top">MPL
Boolean Constant</a>. Convertible to bool.
</p>
</td>
<td>
</td>
<td>
<p>
Constant
</p>
</td>
</tr>
<tr>
<td>
<p>
<code class="computeroutput"><a class="link" href="../intrinsic/functions/front.html" title="front"><code class="computeroutput"><span class="identifier">front</span></code></a><span class="special">(</span><span class="identifier">s</span><span class="special">)</span></code>
</p>
</td>
<td>
<p>
Any type
</p>
</td>
<td>
</td>
<td>
<p>
Constant
</p>
</td>
</tr>
<tr>
<td>
<p>
<code class="computeroutput"><a class="link" href="../intrinsic/functions/front.html" title="front"><code class="computeroutput"><span class="identifier">front</span></code></a><span class="special">(</span><span class="identifier">s</span><span class="special">)</span>
<span class="special">=</span> <span class="identifier">o</span></code>
</p>
</td>
<td>
<p>
Any type
</p>
</td>
<td>
<p>
<code class="computeroutput"><span class="identifier">s</span></code> is mutable
and <code class="computeroutput"><span class="identifier">e</span> <span class="special">=</span>
<span class="identifier">o</span></code>, where <code class="computeroutput"><span class="identifier">e</span></code> is the first element in the
sequence, is a valid expression.
</p>
</td>
<td>
<p>
Constant
</p>
</td>
</tr>
</tbody>
</table></div>
<a name="fusion.sequence.concepts.forward_sequence.result_type_expressions"></a><h6>
<a name="id911389"></a>
<a class="link" href="forward_sequence.html#fusion.sequence.concepts.forward_sequence.result_type_expressions">Result
Type Expressions</a>
</h6>
<div class="informaltable"><table class="table">
<colgroup>
<col>
<col>
</colgroup>
<thead><tr>
<th>
<p>
Expression
</p>
</th>
<th>
<p>
Compile Time Complexity
</p>
</th>
</tr></thead>
<tbody>
<tr>
<td>
<p>
<code class="computeroutput"><a class="link" href="../intrinsic/metafunctions/begin.html" title="begin"><code class="computeroutput"><span class="identifier">result_of</span><span class="special">::</span><span class="identifier">begin</span></code></a><span class="special"><</span><span class="identifier">S</span><span class="special">>::</span><span class="identifier">type</span></code>
</p>
</td>
<td>
<p>
Amortized constant time
</p>
</td>
</tr>
<tr>
<td>
<p>
<code class="computeroutput"><a class="link" href="../intrinsic/metafunctions/end.html" title="end"><code class="computeroutput"><span class="identifier">result_of</span><span class="special">::</span><span class="identifier">end</span></code></a><span class="special"><</span><span class="identifier">S</span><span class="special">>::</span><span class="identifier">type</span></code>
</p>
</td>
<td>
<p>
Amortized constant time
</p>
</td>
</tr>
<tr>
<td>
<p>
<code class="computeroutput"><a class="link" href="../intrinsic/metafunctions/size.html" title="size"><code class="computeroutput"><span class="identifier">result_of</span><span class="special">::</span><span class="identifier">size</span></code></a><span class="special"><</span><span class="identifier">S</span><span class="special">>::</span><span class="identifier">type</span></code>
</p>
</td>
<td>
<p>
Unspecified
</p>
</td>
</tr>
<tr>
<td>
<p>
<code class="computeroutput"><a class="link" href="../intrinsic/metafunctions/empty.html" title="empty"><code class="computeroutput"><span class="identifier">result_of</span><span class="special">::</span><span class="identifier">empty</span></code></a><span class="special"><</span><span class="identifier">S</span><span class="special">>::</span><span class="identifier">type</span></code>
</p>
</td>
<td>
<p>
Constant time
</p>
</td>
</tr>
<tr>
<td>
<p>
<code class="computeroutput"><a class="link" href="../intrinsic/metafunctions/front.html" title="front"><code class="computeroutput"><span class="identifier">result_of</span><span class="special">::</span><span class="identifier">front</span></code></a><span class="special"><</span><span class="identifier">S</span><span class="special">>::</span><span class="identifier">type</span></code>
</p>
</td>
<td>
<p>
Amortized constant time
</p>
</td>
</tr>
</tbody>
</table></div>
<a name="fusion.sequence.concepts.forward_sequence.expression_semantics"></a><h6>
<a name="id912249"></a>
<a class="link" href="forward_sequence.html#fusion.sequence.concepts.forward_sequence.expression_semantics">Expression
Semantics</a>
</h6>
<div class="informaltable"><table class="table">
<colgroup>
<col>
<col>
</colgroup>
<thead><tr>
<th>
<p>
Expression
</p>
</th>
<th>
<p>
Semantics
</p>
</th>
</tr></thead>
<tbody>
<tr>
<td>
<p>
<code class="computeroutput"><a class="link" href="../intrinsic/functions/begin.html" title="begin"><code class="computeroutput"><span class="identifier">begin</span></code></a><span class="special">(</span><span class="identifier">s</span><span class="special">)</span></code>
</p>
</td>
<td>
<p>
An iterator to the first element of the sequence; see <a class="link" href="../intrinsic/functions/begin.html" title="begin"><code class="computeroutput"><span class="identifier">begin</span></code></a>.
</p>
</td>
</tr>
<tr>
<td>
<p>
<code class="computeroutput"><a class="link" href="../intrinsic/functions/end.html" title="end"><code class="computeroutput"><span class="identifier">end</span></code></a><span class="special">(</span><span class="identifier">s</span><span class="special">)</span></code>
</p>
</td>
<td>
<p>
A past-the-end iterator to the sequence; see <a class="link" href="../intrinsic/functions/end.html" title="end"><code class="computeroutput"><span class="identifier">end</span></code></a>.
</p>
</td>
</tr>
<tr>
<td>
<p>
<code class="computeroutput"><a class="link" href="../intrinsic/functions/size.html" title="size"><code class="computeroutput"><span class="identifier">size</span></code></a><span class="special">(</span><span class="identifier">s</span><span class="special">)</span></code>
</p>
</td>
<td>
<p>
The size of the sequence; see <a class="link" href="../intrinsic/functions/size.html" title="size"><code class="computeroutput"><span class="identifier">size</span></code></a>.
</p>
</td>
</tr>
<tr>
<td>
<p>
<code class="computeroutput"><a class="link" href="../intrinsic/functions/empty.html" title="empty"><code class="computeroutput"><span class="identifier">empty</span></code></a><span class="special">(</span><span class="identifier">s</span><span class="special">)</span></code>
</p>
</td>
<td>
<p>
A boolean Integral Constant <code class="computeroutput"><span class="identifier">c</span></code>
such that <code class="computeroutput"><span class="identifier">c</span><span class="special">::</span><span class="identifier">value</span> <span class="special">==</span>
<span class="keyword">true</span></code> if and only if the
sequence is empty; see <a class="link" href="../intrinsic/functions/empty.html" title="empty"><code class="computeroutput"><span class="identifier">empty</span></code></a>.
</p>
</td>
</tr>
<tr>
<td>
<p>
<code class="computeroutput"><a class="link" href="../intrinsic/functions/front.html" title="front"><code class="computeroutput"><span class="identifier">front</span></code></a><span class="special">(</span><span class="identifier">s</span><span class="special">)</span></code>
</p>
</td>
<td>
<p>
The first element in the sequence; see <a class="link" href="../intrinsic/functions/front.html" title="front"><code class="computeroutput"><span class="identifier">front</span></code></a>.
</p>
</td>
</tr>
</tbody>
</table></div>
<a name="fusion.sequence.concepts.forward_sequence.invariants"></a><h6>
<a name="id912585"></a>
<a class="link" href="forward_sequence.html#fusion.sequence.concepts.forward_sequence.invariants">Invariants</a>
</h6>
<p>
For any Forward Sequence s the following invariants always hold:
</p>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
<code class="computeroutput"><span class="special">[</span><a class="link" href="../intrinsic/functions/begin.html" title="begin"><code class="computeroutput"><span class="identifier">begin</span></code></a><span class="special">(</span><span class="identifier">s</span><span class="special">),</span> <a class="link" href="../intrinsic/functions/end.html" title="end"><code class="computeroutput"><span class="identifier">end</span></code></a><span class="special">(</span><span class="identifier">s</span><span class="special">))</span></code> is always a valid range.
</li>
<li class="listitem">
An <a class="link" href="../../algorithm.html" title="Algorithm">Algorithm</a> that iterates
through the range <code class="computeroutput"><span class="special">[</span><a class="link" href="../intrinsic/functions/begin.html" title="begin"><code class="computeroutput"><span class="identifier">begin</span></code></a><span class="special">(</span><span class="identifier">s</span><span class="special">),</span> <a class="link" href="../intrinsic/functions/end.html" title="end"><code class="computeroutput"><span class="identifier">end</span></code></a><span class="special">(</span><span class="identifier">s</span><span class="special">))</span></code> will pass through every element of
<code class="computeroutput"><span class="identifier">s</span></code> exactly once.
</li>
<li class="listitem">
<code class="computeroutput"><a class="link" href="../intrinsic/functions/begin.html" title="begin"><code class="computeroutput"><span class="identifier">begin</span></code></a><span class="special">(</span><span class="identifier">s</span><span class="special">)</span></code>
is identical to <code class="computeroutput"><a class="link" href="../intrinsic/functions/end.html" title="end"><code class="computeroutput"><span class="identifier">end</span></code></a><span class="special">(</span><span class="identifier">s</span><span class="special">))</span></code>
if and only if <code class="computeroutput"><span class="identifier">s</span></code> is
empty.
</li>
<li class="listitem">
Two different iterations through <code class="computeroutput"><span class="identifier">s</span></code>
will access its elements in the same order.
</li>
</ul></div>
<a name="fusion.sequence.concepts.forward_sequence.models"></a><h6>
<a name="id912800"></a>
<a class="link" href="forward_sequence.html#fusion.sequence.concepts.forward_sequence.models">Models</a>
</h6>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
<a class="link" href="../../adapted/std__pair.html" title="std::pair"><code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">pair</span></code></a>
</li>
<li class="listitem">
<a class="link" href="../../adapted/boost__array.html" title="boost::array"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">array</span></code></a>
</li>
<li class="listitem">
<a class="link" href="../../container/vector.html" title="vector"><code class="computeroutput"><span class="identifier">vector</span></code></a>
</li>
<li class="listitem">
<a class="link" href="../../container/cons.html" title="cons"><code class="computeroutput"><span class="identifier">cons</span></code></a>
</li>
<li class="listitem">
<a class="link" href="../../container/list.html" title="list"><code class="computeroutput"><span class="identifier">list</span></code></a>
</li>
<li class="listitem">
<a class="link" href="../../container/set.html" title="set"><code class="computeroutput"><span class="identifier">set</span></code></a>
</li>
<li class="listitem">
<a class="link" href="../../container/map.html" title="map"><code class="computeroutput"><span class="identifier">map</span></code></a>
</li>
<li class="listitem">
<a class="link" href="../../view/single_view.html" title="single_view"><code class="computeroutput"><span class="identifier">single_view</span></code></a>
</li>
<li class="listitem">
<a class="link" href="../../view/filter_view.html" title="filter_view"><code class="computeroutput"><span class="identifier">filter_view</span></code></a>
</li>
<li class="listitem">
<a class="link" href="../../view/iterator_range.html" title="iterator_range"><code class="computeroutput"><span class="identifier">iterator_range</span></code></a>
</li>
<li class="listitem">
<a class="link" href="../../view/joint_view.html" title="joint_view"><code class="computeroutput"><span class="identifier">joint_view</span></code></a>
</li>
<li class="listitem">
<a class="link" href="../../view/transform_view.html" title="transform_view"><code class="computeroutput"><span class="identifier">transform_view</span></code></a>
</li>
<li class="listitem">
<a class="link" href="../../view/reverse_view.html" title="reverse_view"><code class="computeroutput"><span class="identifier">reverse_view</span></code></a>
</li>
<li class="listitem">
<a class="link" href="../../view/zip_view.html" title="zip_view"><code class="computeroutput"><span class="identifier">zip_view</span></code></a>
</li>
</ul></div>
</div>
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<td align="right"><div class="copyright-footer">Copyright © 2001-2007 Joel de Guzman, Dan Marsden, Tobias
Schwinger<p>
Distributed under the Boost Software License, Version 1.0. (See accompanying
file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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