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| </div> |
| <div class="section"> |
| <div class="titlepage"><div><div><h3 class="title"> |
| <a name="fusion.container.cons"></a><a class="link" href="cons.html" title="cons">cons</a> |
| </h3></div></div></div> |
| <a name="fusion.container.cons.description"></a><h5> |
| <a name="id911340"></a> |
| <a class="link" href="cons.html#fusion.container.cons.description">Description</a> |
| </h5> |
| <p> |
| <code class="computeroutput"><span class="identifier">cons</span></code> is a simple <a class="link" href="../sequence/concepts/forward_sequence.html" title="Forward Sequence">Forward |
| Sequence</a>. It is a lisp style recursive list structure where <code class="computeroutput"><span class="identifier">car</span></code> is the <span class="emphasis"><em>head</em></span> and |
| <code class="computeroutput"><span class="identifier">cdr</span></code> is the <span class="emphasis"><em>tail</em></span>: |
| usually another cons structure or <code class="computeroutput"><span class="identifier">nil</span></code>: |
| the empty list. Fusion's <a class="link" href="list.html" title="list"><code class="computeroutput"><span class="identifier">list</span></code></a> is built on top of this more |
| primitive data structure. It is more efficient than <a class="link" 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 class="link" href="../notes.html#fusion.notes.recursive_inlined_functions">Recursive |
| Inlined Functions</a>). |
| </p> |
| <a name="fusion.container.cons.header"></a><h5> |
| <a name="id911421"></a> |
| <a class="link" href="cons.html#fusion.container.cons.header">Header</a> |
| </h5> |
| <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">fusion</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">cons</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> |
| <span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">fusion</span><span class="special">/</span><span class="identifier">include</span><span class="special">/</span><span class="identifier">cons</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> |
| </pre> |
| <a name="fusion.container.cons.synopsis"></a><h5> |
| <a name="id911537"></a> |
| <a class="link" href="cons.html#fusion.container.cons.synopsis">Synopsis</a> |
| </h5> |
| <pre class="programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Car</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Cdr</span> <span class="special">=</span> <span class="identifier">nil</span><span class="special">></span> |
| <span class="keyword">struct</span> <span class="identifier">cons</span><span class="special">;</span> |
| </pre> |
| <a name="fusion.container.cons.template_parameters"></a><h5> |
| <a name="id911611"></a> |
| <a class="link" href="cons.html#fusion.container.cons.template_parameters">Template parameters</a> |
| </h5> |
| <div class="informaltable"><table class="table"> |
| <colgroup> |
| <col> |
| <col> |
| <col> |
| </colgroup> |
| <thead><tr> |
| <th> |
| <p> |
| Parameter |
| </p> |
| </th> |
| <th> |
| <p> |
| Description |
| </p> |
| </th> |
| <th> |
| <p> |
| Default |
| </p> |
| </th> |
| </tr></thead> |
| <tbody> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">Car</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Head type |
| </p> |
| </td> |
| <td> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">Cdr</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Tail type |
| </p> |
| </td> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">nil</span></code> |
| </p> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| <a name="fusion.container.cons.model_of"></a><h5> |
| <a name="id911735"></a> |
| <a class="link" href="cons.html#fusion.container.cons.model_of">Model of</a> |
| </h5> |
| <div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"> |
| <a class="link" href="../sequence/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">nil</span></code></span></dt> |
| <dd><p> |
| An empty <code class="computeroutput"><span class="identifier">cons</span></code> |
| </p></dd> |
| <dt><span class="term"><code class="computeroutput"><span class="identifier">C</span></code></span></dt> |
| <dd><p> |
| A <code class="computeroutput"><span class="identifier">cons</span></code> type |
| </p></dd> |
| <dt><span class="term"><code class="computeroutput"><span class="identifier">l</span></code>, <code class="computeroutput"><span class="identifier">l2</span></code></span></dt> |
| <dd><p> |
| Instances of <code class="computeroutput"><span class="identifier">cons</span></code> |
| </p></dd> |
| <dt><span class="term"><code class="computeroutput"><span class="identifier">car</span></code></span></dt> |
| <dd><p> |
| An arbitrary data |
| </p></dd> |
| <dt><span class="term"><code class="computeroutput"><span class="identifier">cdr</span></code></span></dt> |
| <dd><p> |
| Another <code class="computeroutput"><span class="identifier">cons</span></code> list |
| </p></dd> |
| <dt><span class="term"><code class="computeroutput"><span class="identifier">s</span></code></span></dt> |
| <dd><p> |
| A <a class="link" href="../sequence/concepts/forward_sequence.html" title="Forward Sequence">Forward |
| Sequence</a> |
| </p></dd> |
| <dt><span class="term"><code class="computeroutput"><span class="identifier">N</span></code></span></dt> |
| <dd><p> |
| An <a href="http://www.boost.org/libs/mpl/doc/refmanual/integral-constant.html" target="_top">MPL |
| Integral Constant</a> |
| </p></dd> |
| </dl> |
| </div> |
| <a name="fusion.container.cons.expression_semantics"></a><h5> |
| <a name="id913043"></a> |
| <a class="link" href="cons.html#fusion.container.cons.expression_semantics">Expression Semantics</a> |
| </h5> |
| <p> |
| Semantics of an expression is defined only where it differs from, or is not |
| defined in <a class="link" href="../sequence/concepts/forward_sequence.html" title="Forward Sequence">Forward |
| Sequence</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="identifier">nil</span><span class="special">()</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Creates an empty list. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">C</span><span class="special">()</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Creates a cons with default constructed elements. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">C</span><span class="special">(</span><span class="identifier">car</span><span class="special">)</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Creates a cons with <code class="computeroutput"><span class="identifier">car</span></code> |
| head and default constructed tail. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">C</span><span class="special">(</span><span class="identifier">car</span><span class="special">,</span> |
| <span class="identifier">cdr</span><span class="special">)</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Creates a cons with <code class="computeroutput"><span class="identifier">car</span></code> |
| head and <code class="computeroutput"><span class="identifier">cdr</span></code> tail. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">C</span><span class="special">(</span><span class="identifier">s</span><span class="special">)</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Copy constructs a cons from a <a class="link" href="../sequence/concepts/forward_sequence.html" title="Forward Sequence">Forward |
| Sequence</a>, <code class="computeroutput"><span class="identifier">s</span></code>. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">l</span> <span class="special">=</span> |
| <span class="identifier">s</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Assigns to a cons, <code class="computeroutput"><span class="identifier">l</span></code>, |
| from a <a class="link" href="../sequence/concepts/forward_sequence.html" title="Forward Sequence">Forward |
| Sequence</a>, <code class="computeroutput"><span class="identifier">s</span></code>. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><a class="link" href="../sequence/intrinsic/functions/at.html" title="at"><code class="computeroutput"><span class="identifier">at</span></code></a><span class="special"><</span><span class="identifier">N</span><span class="special">>(</span><span class="identifier">l</span><span class="special">)</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| The Nth element from the beginning of the sequence; see <a class="link" href="../sequence/intrinsic/functions/at.html" title="at"><code class="computeroutput"><span class="identifier">at</span></code></a>. |
| </p> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| <div class="sidebar"> |
| <p class="title"><b></b></p> |
| <p> |
| <span class="inlinemediaobject"><img src="../../images/note.png" alt="note"></span> <code class="computeroutput"><a class="link" href="../sequence/intrinsic/functions/at.html" title="at"><code class="computeroutput"><span class="identifier">at</span></code></a><span class="special"><</span><span class="identifier">N</span><span class="special">>(</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">cons</span></code> being |
| a <a class="link" href="../sequence/concepts/forward_sequence.html" title="Forward Sequence">Forward Sequence</a> |
| only (<code class="computeroutput"><span class="identifier">at</span></code> is supposed to be |
| a <a class="link" href="../sequence/concepts/random_access_sequence.html" title="Random Access Sequence">Random |
| Access Sequence</a> requirement). The runtime complexity of <a class="link" href="../sequence/intrinsic/functions/at.html" title="at"><code class="computeroutput"><span class="identifier">at</span></code></a> is constant (see <a class="link" href="../notes.html#fusion.notes.recursive_inlined_functions">Recursive |
| Inlined Functions</a>). |
| </p> |
| </div> |
| <a name="fusion.container.cons.example"></a><h5> |
| <a name="id913517"></a> |
| <a class="link" href="cons.html#fusion.container.cons.example">Example</a> |
| </h5> |
| <pre class="programlisting"><span class="identifier">cons</span><span class="special"><</span><span class="keyword">int</span><span class="special">,</span> <span class="identifier">cons</span><span class="special"><</span><span class="keyword">float</span><span class="special">></span> <span class="special">></span> <span class="identifier">l</span><span class="special">(</span><span class="number">12</span><span class="special">,</span> <span class="identifier">cons</span><span class="special"><</span><span class="keyword">float</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"><<</span> <a class="link" href="../sequence/intrinsic/functions/at_c.html" title="at_c"><code class="computeroutput"><span class="identifier">at_c</span></code></a><span class="special"><</span><span class="number">0</span><span class="special">>(</span><span class="identifier">l</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> |
| <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <a class="link" href="../sequence/intrinsic/functions/at_c.html" title="at_c"><code class="computeroutput"><span class="identifier">at_c</span></code></a><span class="special"><</span><span class="number">1</span><span class="special">>(</span><span class="identifier">l</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> |
| </div> |
| <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> |
| <td align="left"></td> |
| <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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