boost_fusion/doc/html/fusion/sequences/containers/list.html

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<div class="titlepage"><div><div><h4 class="title">
<a name="fusion.sequences.containers.list"></a><a href="list.html" title="list">list</a></h4></div></div></div>
<a name="fusion.sequences.containers.list.description"></a><h5>
<a name="id970861"></a>
          <a href="list.html#fusion.sequences.containers.list.description">Description</a>
        </h5>
<p>
          <code class="computeroutput"><span class="identifier">list</span></code> is a <a href="../concepts/forward_sequence.html" title="Forward
        Sequence">Forward
          Sequence</a> of heterogenous typed data built on top of <a href="cons.html" title="cons"><code class="computeroutput"><span class="identifier">cons</span></code></a>. It is more efficient than
          <a href="vector.html" title="vector"><code class="computeroutput"><span class="identifier">vector</span></code></a>
          when the target sequence is constructed piecemeal (a data at a time). The
          runtime cost of access to each element is peculiarly constant (see <a href="../../notes.html#fusion.notes.recursive_inlined_functions">Recursive Inlined Functions</a>).
        </p>
<a name="fusion.sequences.containers.list.header"></a><h5>
<a name="id970944"></a>
          <a href="list.html#fusion.sequences.containers.list.header">Header</a>
        </h5>
<pre class="programlisting">
<span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">fusion</span><span class="special">/</span><span class="identifier">sequence</span><span class="special">/</span><span class="identifier">container</span><span class="special">/</span><span class="identifier">list</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
<span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">fusion</span><span class="special">/</span><span class="identifier">sequence</span><span class="special">/</span><span class="identifier">container</span><span class="special">/</span><span class="identifier">list</span><span class="special">/</span><span class="identifier">list_forward</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
</pre>
<a name="fusion.sequences.containers.list.synopsis"></a><h5>
<a name="id971108"></a>
          <a href="list.html#fusion.sequences.containers.list.synopsis">Synopsis</a>
        </h5>
<pre class="programlisting">
<span class="keyword">template</span> <span class="special">&lt;</span>
    <span class="keyword">typename</span> <span class="identifier">T0</span> <span class="special">=</span> <span class="emphasis"><em>unspecified</em></span>
  <span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">T1</span> <span class="special">=</span> <span class="emphasis"><em>unspecified</em></span>
  <span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">T2</span> <span class="special">=</span> <span class="emphasis"><em>unspecified</em></span>
    <span class="special">...</span>
  <span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">TN</span> <span class="special">=</span> <span class="emphasis"><em>unspecified</em></span>
<span class="special">&gt;</span>
<span class="keyword">struct</span> <span class="identifier">list</span><span class="special">;</span>
</pre>
<p>
          The variadic class interface accepts <code class="computeroutput"><span class="number">0</span></code>
          to <code class="computeroutput"><span class="identifier">FUSION_MAX_LIST_SIZE</span></code>
          elements, where <code class="computeroutput"><span class="identifier">FUSION_MAX_LIST_SIZE</span></code>
          is a user definable predefined maximum that defaults to <code class="computeroutput"><span class="number">10</span></code>.
          Example:
        </p>
<pre class="programlisting">
<span class="identifier">list</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">,</span> <span class="keyword">char</span><span class="special">,</span> <span class="keyword">double</span><span class="special">&gt;</span>
</pre>
<p>
          You may define the preprocessor constant <code class="computeroutput"><span class="identifier">FUSION_MAX_LIST_SIZE</span></code>
          before including any Fusion header to change the default. Example:
        </p>
<pre class="programlisting">
<span class="preprocessor">#define</span> <span class="identifier">FUSION_MAX_LIST_SIZE</span> <span class="number">20</span>
</pre>
<a name="fusion.sequences.containers.list.template_parameters"></a><h5>
<a name="id971390"></a>
          <a href="list.html#fusion.sequences.containers.list.template_parameters">Template
          parameters</a>
        </h5>
<div class="informaltable"><table class="table">
<colgroup>
<col>
<col>
<col>
</colgroup>
<thead><tr>
<th>Parameter</th>
<th>Description</th>
<th>Default</th>
</tr></thead>
<tbody><tr>
<td>
<code class="computeroutput"><span class="identifier">T0</span></code>...<code class="computeroutput"><span class="identifier">TN</span></code>
</td>
<td>Element types</td>
<td><span class="emphasis"><em>unspecified-type</em></span></td>
</tr></tbody>
</table></div>
<a name="fusion.sequences.containers.list.model_of"></a><h5>
<a name="id971470"></a>
          <a href="list.html#fusion.sequences.containers.list.model_of">Model of</a>
        </h5>
<div class="itemizedlist"><ul type="disc"><li><a href="../concepts/forward_sequence.html" title="Forward
        Sequence">Forward Sequence</a></li></ul></div>
<div class="variablelist">
<p class="title"><b>Notation</b></p>
<dl>
<dt><span class="term"><code class="computeroutput"><span class="identifier">L</span></code></span></dt>
<dd>
            A <code class="computeroutput"><span class="identifier">list</span></code> type
          </dd>
<dt><span class="term"><code class="computeroutput"><span class="identifier">l</span></code></span></dt>
<dd>
            An instance of <code class="computeroutput"><span class="identifier">list</span></code>
</dd>
<dt><span class="term"><code class="computeroutput"><span class="identifier">e0</span></code>...<code class="computeroutput"><span class="identifier">en</span></code></span></dt>
<dd>
            Heterogeneous values
          </dd>
<dt><span class="term"><code class="computeroutput"><span class="identifier">s</span></code></span></dt>
<dd>
            A <a href="../concepts/forward_sequence.html" title="Forward
        Sequence">Forward
            Sequence</a>
</dd>
<dt><span class="term"><code class="computeroutput"><span class="identifier">N</span></code></span></dt>
<dd>
            An Integral Constant
          </dd>
</dl>
</div>
<a name="fusion.sequences.containers.list.expression_semantics"></a><h5>
<a name="id971625"></a>
          <a href="list.html#fusion.sequences.containers.list.expression_semantics">Expression
          Semantics</a>
        </h5>
<p>
          Semantics of an expression is defined only where it differs from, or is
          not defined in <a href="../concepts/forward_sequence.html" title="Forward
        Sequence">Forward
          Sequence</a>.
        </p>
<div class="informaltable"><table class="table">
<colgroup>
<col>
<col>
</colgroup>
<thead><tr>
<th>Expression</th>
<th>Semantics</th>
</tr></thead>
<tbody>
<tr>
<td><code class="computeroutput"><span class="identifier">L</span><span class="special">()</span></code></td>
<td>Creates
                a list with default constructed elements.</td>
</tr>
<tr>
<td><code class="computeroutput"><span class="identifier">L</span><span class="special">(</span><span class="identifier">e0</span><span class="special">,</span> <span class="identifier">e1</span><span class="special">,...</span>
                <span class="identifier">en</span><span class="special">)</span></code></td>
<td>Creates
                a list with elements <code class="computeroutput"><span class="identifier">e0</span></code>...<code class="computeroutput"><span class="identifier">en</span></code>.</td>
</tr>
<tr>
<td><code class="computeroutput"><span class="identifier">L</span><span class="special">(</span><span class="identifier">s</span><span class="special">)</span></code></td>
<td>Copy
                constructs a list from a <a href="../concepts/forward_sequence.html" title="Forward
        Sequence">Forward
                Sequence</a>, <code class="computeroutput"><span class="identifier">s</span></code>.</td>
</tr>
<tr>
<td><code class="computeroutput"><span class="identifier">l</span> <span class="special">=</span>
                <span class="identifier">s</span></code></td>
<td>Assigns
                to a list, <code class="computeroutput"><span class="identifier">l</span></code>, from
                a <a href="../concepts/forward_sequence.html" title="Forward
        Sequence">Forward
                Sequence</a>, <code class="computeroutput"><span class="identifier">s</span></code>.</td>
</tr>
<tr>
<td><code class="computeroutput"><a href="../intrinsics/functions/at.html" title="at"><code class="computeroutput"><span class="identifier">at</span></code></a><span class="special">&lt;</span><span class="identifier">N</span><span class="special">&gt;(</span><span class="identifier">l</span><span class="special">)</span></code></td>
<td>The
                Nth element from the beginning of the sequence; see <a href="../intrinsics/functions/at.html" title="at"><code class="computeroutput"><span class="identifier">at</span></code></a>.</td>
</tr>
</tbody>
</table></div>
<p class="blurb">
          <span class="inlinemediaobject"><img src="../../../images/note.png" alt="note"></span> <code class="computeroutput"><a href="../intrinsics/functions/at.html" title="at"><code class="computeroutput"><span class="identifier">at</span></code></a><span class="special">&lt;</span><span class="identifier">n</span><span class="special">&gt;(</span><span class="identifier">l</span><span class="special">)</span></code> is
          provided for convenience and compatibility with the original <a href="http://www.boost.org/libs/tuple/doc/tuple_users_guide.html" target="_top">Boost.Tuple</a>
          library, despite <code class="computeroutput"><span class="identifier">list</span></code> being
          a <a href="../concepts/forward_sequence.html" title="Forward
        Sequence">Forward Sequence</a>
          only (<a href="../intrinsics/functions/at.html" title="at"><code class="computeroutput"><span class="identifier">at</span></code></a> is supposed to be a <a href="../concepts/random_access_sequence.html" title="Random
        Access Sequence">Random
          Access Sequence</a> requirement). The runtime complexity of <a href="../intrinsics/functions/at.html" title="at"><code class="computeroutput"><span class="identifier">at</span></code></a> is constant (see <a href="../../notes.html#fusion.notes.recursive_inlined_functions">Recursive
          Inlined Functions</a>).
        </p>
<a name="fusion.sequences.containers.list.example"></a><h5>
<a name="id972064"></a>
          <a href="list.html#fusion.sequences.containers.list.example">Example</a>
        </h5>
<pre class="programlisting">
<span class="identifier">list</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">,</span> <span class="keyword">float</span><span class="special">&gt;</span> <span class="identifier">l</span><span class="special">(</span><span class="number">12</span><span class="special">,</span> <span class="number">5.5f</span><span class="special">);</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <a href="../intrinsics/functions/at.html" title="at"><code class="computeroutput"><span class="identifier">at</span></code></a><span class="special">&lt;</span><span class="number">0</span><span class="special">&gt;(</span><span class="identifier">l</span><span class="special">)</span> <span class="special">&lt;&lt;</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <a href="../intrinsics/functions/at.html" title="at"><code class="computeroutput"><span class="identifier">at</span></code></a><span class="special">&lt;</span><span class="number">1</span><span class="special">&gt;(</span><span class="identifier">l</span><span class="special">)</span> <span class="special">&lt;&lt;</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span>
</pre>
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