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<div class="titlepage"><div><div><h5 class="title">
<a name="spirit.qi.reference.operator.plus"></a><a class="link" href="plus.html" title="Plus (+a)"> Plus (<code class="computeroutput"><span class="special">+</span><span class="identifier">a</span></code>)</a>
</h5></div></div></div>
<a name="spirit.qi.reference.operator.plus.description"></a><h6>
<a name="id981363"></a>
<a class="link" href="plus.html#spirit.qi.reference.operator.plus.description">Description</a>
</h6>
<p>
The plus operator, <code class="computeroutput"><span class="special">+</span><span class="identifier">a</span></code>,
is a unary operator that matches its operand one or more times.
</p>
<a name="spirit.qi.reference.operator.plus.header"></a><h6>
<a name="id981391"></a>
<a class="link" href="plus.html#spirit.qi.reference.operator.plus.header">Header</a>
</h6>
<pre class="programlisting"><span class="comment">// forwards to <boost/spirit/home/qi/operator/plus.hpp>
</span><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">spirit</span><span class="special">/</span><span class="identifier">include</span><span class="special">/</span><span class="identifier">qi_plus</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span>
</pre>
<p>
Also, see <a class="link" href="../../../structure/include.html" title="Include">Include Structure</a>.
</p>
<a name="spirit.qi.reference.operator.plus.model_of"></a><h6>
<a name="id981465"></a>
<a class="link" href="plus.html#spirit.qi.reference.operator.plus.model_of">Model of</a>
</h6>
<div class="blockquote"><blockquote class="blockquote"><p>
<a class="link" href="../parser_concepts/unaryparser.html" title="UnaryParser"><code class="computeroutput"><span class="identifier">UnaryParser</span></code></a>
</p></blockquote></div>
<div class="variablelist">
<p class="title"><b>Notation</b></p>
<dl>
<dt><span class="term"><code class="computeroutput"><span class="identifier">a</span></code></span></dt>
<dd><p>
A <a class="link" href="../parser_concepts/parser.html" title="Parser"><code class="computeroutput"><span class="identifier">Parser</span></code></a>
</p></dd>
</dl>
</div>
<a name="spirit.qi.reference.operator.plus.expression_semantics"></a><h6>
<a name="id981531"></a>
<a class="link" href="plus.html#spirit.qi.reference.operator.plus.expression_semantics">Expression
Semantics</a>
</h6>
<p>
Semantics of an expression is defined only where it differs from, or
is not defined in <a class="link" href="../parser_concepts/unaryparser.html" title="UnaryParser"><code class="computeroutput"><span class="identifier">UnaryParser</span></code></a>.
</p>
<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"><span class="special">+</span><span class="identifier">a</span></code>
</p>
</td>
<td>
<p>
Match <code class="computeroutput"><span class="identifier">a</span></code> one
or more times.
</p>
</td>
</tr></tbody>
</table></div>
<a name="spirit.qi.reference.operator.plus.attributes"></a><h6>
<a name="id981629"></a>
<a class="link" href="plus.html#spirit.qi.reference.operator.plus.attributes">Attributes</a>
</h6>
<p>
See <a class="link" href="../../quick_reference/compound_attribute_rules.html#spirit.qi.quick_reference.compound_attribute_rules.notation">Compound
Attribute Notation</a>.
</p>
<div class="informaltable"><table class="table">
<colgroup>
<col>
<col>
</colgroup>
<thead><tr>
<th>
<p>
Expression
</p>
</th>
<th>
<p>
Attribute
</p>
</th>
</tr></thead>
<tbody><tr>
<td>
<p>
<code class="computeroutput"><span class="special">+</span><span class="identifier">a</span></code>
</p>
</td>
<td>
<p>
</p>
<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="identifier">a</span><span class="special">:</span> <span class="identifier">A</span> <span class="special">--></span> <span class="special">+</span><span class="identifier">a</span><span class="special">:</span> <span class="identifier">vector</span><span class="special"><</span><span class="identifier">A</span><span class="special">></span>
<span class="identifier">a</span><span class="special">:</span> <span class="identifier">Unused</span> <span class="special">--></span> <span class="special">+</span><span class="identifier">a</span><span class="special">:</span> <span class="identifier">Unused</span></pre>
<p>
</p>
</td>
</tr></tbody>
</table></div>
<a name="spirit.qi.reference.operator.plus.complexity"></a><h6>
<a name="id981800"></a>
<a class="link" href="plus.html#spirit.qi.reference.operator.plus.complexity">Complexity</a>
</h6>
<div class="blockquote"><blockquote class="blockquote"><p>
The overall complexity of the Plus is defined by the complexity of
its subject, <code class="computeroutput"><span class="identifier">a</span></code>, multiplied
by the number of repetitions. The complexity of the Plus itself is
O(N), where N is the number successful repetitions.
</p></blockquote></div>
<a name="spirit.qi.reference.operator.plus.example"></a><h6>
<a name="id981827"></a>
<a class="link" href="plus.html#spirit.qi.reference.operator.plus.example">Example</a>
</h6>
<div class="note"><table border="0" summary="Note">
<tr>
<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../images/note.png"></td>
<th align="left">Note</th>
</tr>
<tr><td align="left" valign="top"><p>
The test harness for the example(s) below is presented in the <a class="link" href="../basics.html#spirit.qi.reference.basics.examples">Basics Examples</a>
section.
</p></td></tr>
</table></div>
<p>
Some using declarations:
</p>
<p>
</p>
<pre class="programlisting"><span class="keyword">using</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">spirit</span><span class="special">::</span><span class="identifier">ascii</span><span class="special">::</span><span class="identifier">alpha</span><span class="special">;</span>
<span class="keyword">using</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">spirit</span><span class="special">::</span><span class="identifier">qi</span><span class="special">::</span><span class="identifier">lexeme</span><span class="special">;</span></pre>
<p>
</p>
<p>
Parse one or more strings containing one or more alphabetic characters
and put them in a vector:
</p>
<p>
</p>
<pre class="programlisting"><span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">></span> <span class="identifier">attr</span><span class="special">;</span>
<span class="identifier">test_phrase_parser_attr</span><span class="special">(</span><span class="string">"yaba daba doo"</span><span class="special">,</span> <span class="special">+</span><span class="identifier">lexeme</span><span class="special">[+</span><span class="identifier">alpha</span><span class="special">],</span> <span class="identifier">attr</span><span class="special">);</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="identifier">attr</span><span class="special">[</span><span class="number">0</span><span class="special">]</span> <span class="special"><<</span> <span class="char">','</span> <span class="special"><<</span> <span class="identifier">attr</span><span class="special">[</span><span class="number">1</span><span class="special">]</span> <span class="special"><<</span> <span class="char">','</span> <span class="special"><<</span> <span class="identifier">attr</span><span class="special">[</span><span class="number">2</span><span class="special">]</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span>
</pre>
<p>
</p>
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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