<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> <title>Iterator Facade</title> <link rel="stylesheet" href="../../../../../../doc/src/boostbook.css" type="text/css"> <meta name="generator" content="DocBook XSL Stylesheets V1.75.2"> <link rel="home" href="../../index.html" title="Chapter 1. Fusion 2.0"> <link rel="up" href="../extension.html" title="Extension"> <link rel="prev" href="sequence_facade.html" title="Sequence Facade"> <link rel="next" href="../functional.html" title="Functional"> </head> <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> <table cellpadding="2" width="100%"><tr> <td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../boost.png"></td> <td align="center"><a href="../../../../../../index.html">Home</a></td> <td align="center"><a href="../../../../../../libs/libraries.htm">Libraries</a></td> <td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> <td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> <td align="center"><a href="../../../../../../more/index.htm">More</a></td> </tr></table> <hr> <div class="spirit-nav"> <a accesskey="p" href="sequence_facade.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../extension.html"><img src="../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="../functional.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> </div> <div class="section"> <div class="titlepage"><div><div><h3 class="title"> <a name="fusion.extension.iterator_facade"></a><a class="link" href="iterator_facade.html" title="Iterator Facade">Iterator Facade</a> </h3></div></div></div> <a name="fusion.extension.iterator_facade.description"></a><h5> <a name="id1101334"></a> <a class="link" href="iterator_facade.html#fusion.extension.iterator_facade.description">Description</a> </h5> <p> The <a class="link" href="iterator_facade.html" title="Iterator Facade"><code class="computeroutput"><span class="identifier">iterator_facade</span></code></a> template provides an intrusive mechanism for producing a conforming Fusion iterator. </p> <a name="fusion.extension.iterator_facade.synopsis"></a><h5> <a name="id1101360"></a> <a class="link" href="iterator_facade.html#fusion.extension.iterator_facade.synopsis">Synopsis</a> </h5> <pre class="programlisting"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Derived</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">TravesalTag</span><span class="special">></span> <span class="keyword">struct</span> <span class="identifier">iterator_facade</span><span class="special">;</span> </pre> <a name="fusion.extension.iterator_facade.usage"></a><h5> <a name="id1101424"></a> <a class="link" href="iterator_facade.html#fusion.extension.iterator_facade.usage">Usage</a> </h5> <p> The user of iterator_facade derives his iterator type from a specialization of iterator_facade and passes the derived iterator type as the first template parameter. The second template parameter should be the traversal category of the iterator being implemented. </p> <p> The user must the implement the key expressions required by their iterator type. </p> <div class="table"> <a name="id1101440"></a><p class="title"><b>Table 1.103. Parameters</b></p> <div class="table-contents"><table class="table" summary="Parameters"> <colgroup> <col> <col> </colgroup> <thead><tr> <th> <p> Name </p> </th> <th> <p> Description </p> </th> </tr></thead> <tbody> <tr> <td> <p> <code class="computeroutput"><span class="identifier">iterator</span></code>, <code class="computeroutput"><span class="identifier">It</span></code>, <code class="computeroutput"><span class="identifier">It1</span></code>, <code class="computeroutput"><span class="identifier">It2</span></code> </p> </td> <td> <p> A type derived from <a class="link" href="iterator_facade.html" title="Iterator Facade"><code class="computeroutput"><span class="identifier">iterator_facade</span></code></a> </p> </td> </tr> <tr> <td> <p> <code class="computeroutput"><span class="identifier">N</span></code> </p> </td> <td> <p> An <a href="http://www.boost.org/libs/mpl/doc/refmanual/integral-constant.html" target="_top">MPL Integral Constant</a> </p> </td> </tr> </tbody> </table></div> </div> <br class="table-break"><div class="table"> <a name="id1101565"></a><p class="title"><b>Table 1.104. Key Expressions</b></p> <div class="table-contents"><table class="table" summary="Key Expressions"> <colgroup> <col> <col> <col> </colgroup> <thead><tr> <th> <p> Expression </p> </th> <th> <p> Result </p> </th> <th> <p> Default </p> </th> </tr></thead> <tbody> <tr> <td> <p> <code class="computeroutput"><span class="identifier">iterator</span><span class="special">::</span><span class="keyword">template</span> <span class="identifier">value_of</span><span class="special"><</span><span class="identifier">It</span><span class="special">>::</span><span class="identifier">type</span></code> </p> </td> <td> <p> The element stored at iterator position <code class="computeroutput"><span class="identifier">It</span></code> </p> </td> <td> <p> None </p> </td> </tr> <tr> <td> <p> <code class="computeroutput"><span class="identifier">iterator</span><span class="special">::</span><span class="keyword">template</span> <span class="identifier">deref</span><span class="special"><</span><span class="identifier">It</span><span class="special">>::</span><span class="identifier">type</span></code> </p> </td> <td> <p> The type returned when dereferencing an iterator of type <code class="computeroutput"><span class="identifier">It</span></code> </p> </td> <td> <p> None </p> </td> </tr> <tr> <td> <p> <code class="computeroutput"><span class="identifier">iterator</span><span class="special">::</span><span class="keyword">template</span> <span class="identifier">deref</span><span class="special"><</span><span class="identifier">It</span><span class="special">>::</span><span class="identifier">call</span><span class="special">(</span><span class="identifier">it</span><span class="special">)</span></code> </p> </td> <td> <p> Dereferences iterator <code class="computeroutput"><span class="identifier">it</span></code> </p> </td> <td> <p> None </p> </td> </tr> <tr> <td> <p> <code class="computeroutput"><span class="identifier">iterator</span><span class="special">::</span><span class="keyword">template</span> <span class="identifier">next</span><span class="special"><</span><span class="identifier">It</span><span class="special">>::</span><span class="identifier">type</span></code> </p> </td> <td> <p> The type of the next element from <code class="computeroutput"><span class="identifier">It</span></code> </p> </td> <td> <p> None </p> </td> </tr> <tr> <td> <p> <code class="computeroutput"><span class="identifier">iterator</span><span class="special">::</span><span class="keyword">template</span> <span class="identifier">next</span><span class="special"><</span><span class="identifier">It</span><span class="special">>::</span><span class="identifier">call</span><span class="special">(</span><span class="identifier">it</span><span class="special">)</span></code> </p> </td> <td> <p> The next iterator after <code class="computeroutput"><span class="identifier">it</span></code> </p> </td> <td> <p> None </p> </td> </tr> <tr> <td> <p> <code class="computeroutput"><span class="identifier">iterator</span><span class="special">::</span><span class="keyword">template</span> <span class="identifier">prior</span><span class="special"><</span><span class="identifier">It</span><span class="special">>::</span><span class="identifier">type</span></code> </p> </td> <td> <p> The type of the next element from <code class="computeroutput"><span class="identifier">It</span></code> </p> </td> <td> <p> None </p> </td> </tr> <tr> <td> <p> <code class="computeroutput"><span class="identifier">iterator</span><span class="special">::</span><span class="keyword">template</span> <span class="identifier">prior</span><span class="special"><</span><span class="identifier">It</span><span class="special">>::</span><span class="identifier">call</span><span class="special">(</span><span class="identifier">it</span><span class="special">)</span></code> </p> </td> <td> <p> The next iterator after <code class="computeroutput"><span class="identifier">it</span></code> </p> </td> <td> <p> None </p> </td> </tr> <tr> <td> <p> <code class="computeroutput"><span class="identifier">iterator</span><span class="special">::</span><span class="keyword">template</span> <span class="identifier">advance</span><span class="special"><</span><span class="identifier">It</span><span class="special">,</span> <span class="identifier">N</span><span class="special">>::</span><span class="identifier">type</span></code> </p> </td> <td> <p> The type of an iterator advanced <code class="computeroutput"><span class="identifier">N</span></code> elements from <code class="computeroutput"><span class="identifier">It</span></code> </p> </td> <td> <p> Implemented in terms of <code class="computeroutput"><span class="identifier">next</span></code> and <code class="computeroutput"><span class="identifier">prior</span></code> </p> </td> </tr> <tr> <td> <p> <code class="computeroutput"><span class="identifier">iterator</span><span class="special">::</span><span class="keyword">template</span> <span class="identifier">advance</span><span class="special"><</span><span class="identifier">It</span><span class="special">,</span> <span class="identifier">N</span><span class="special">>::</span><span class="identifier">call</span><span class="special">(</span><span class="identifier">it</span><span class="special">)</span></code> </p> </td> <td> <p> An iterator advanced <code class="computeroutput"><span class="identifier">N</span></code> elements from <code class="computeroutput"><span class="identifier">it</span></code> </p> </td> <td> <p> Implemented in terms of <code class="computeroutput"><span class="identifier">next</span></code> and <code class="computeroutput"><span class="identifier">prior</span></code> </p> </td> </tr> <tr> <td> <p> <code class="computeroutput"><span class="identifier">iterator</span><span class="special">::</span><span class="keyword">template</span> <span class="identifier">distance</span><span class="special"><</span><span class="identifier">It1</span><span class="special">,</span> <span class="identifier">It2</span><span class="special">>::</span><span class="identifier">type</span></code> </p> </td> <td> <p> The distance between iterators of type <code class="computeroutput"><span class="identifier">It1</span></code> and <code class="computeroutput"><span class="identifier">It2</span></code> as an <a href="http://www.boost.org/libs/mpl/doc/refmanual/integral-constant.html" target="_top">MPL Integral Constant</a> </p> </td> <td> <p> None </p> </td> </tr> <tr> <td> <p> <code class="computeroutput"><span class="identifier">iterator</span><span class="special">::</span><span class="keyword">template</span> <span class="identifier">distance</span><span class="special"><</span><span class="identifier">It1</span><span class="special">,</span> <span class="identifier">It2</span><span class="special">>::</span><span class="identifier">call</span><span class="special">(</span><span class="identifier">it1</span><span class="special">,</span> <span class="identifier">it2</span><span class="special">)</span></code> </p> </td> <td> <p> The distance between iterator <code class="computeroutput"><span class="identifier">it1</span></code> and <code class="computeroutput"><span class="identifier">it2</span></code> </p> </td> <td> <p> None </p> </td> </tr> <tr> <td> <p> <code class="computeroutput"><span class="identifier">iterator</span><span class="special">::</span><span class="keyword">template</span> <span class="identifier">equal_to</span><span class="special"><</span><span class="identifier">It1</span><span class="special">,</span> <span class="identifier">It2</span><span class="special">>::</span><span class="identifier">type</span></code> </p> </td> <td> <p> The distance between iterators of type <code class="computeroutput"><span class="identifier">It1</span></code> and <code class="computeroutput"><span class="identifier">It2</span></code> </p> </td> <td> <p> <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">same_type</span><span class="special"><</span><span class="identifier">It1</span><span class="special">,</span> <span class="identifier">It2</span><span class="special">>::</span><span class="identifier">type</span></code> </p> </td> </tr> <tr> <td> <p> <code class="computeroutput"><span class="identifier">iterator</span><span class="special">::</span><span class="keyword">template</span> <span class="identifier">equal_to</span><span class="special"><</span><span class="identifier">It1</span><span class="special">,</span> <span class="identifier">It2</span><span class="special">>::</span><span class="identifier">call</span><span class="special">(</span><span class="identifier">it1</span><span class="special">,</span> <span class="identifier">it2</span><span class="special">)</span></code> </p> </td> <td> <p> The distance between iterators <code class="computeroutput"><span class="identifier">it1</span></code> and <code class="computeroutput"><span class="identifier">it2</span></code> </p> </td> <td> <p> <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">same_type</span><span class="special"><</span><span class="identifier">It1</span><span class="special">,</span> <span class="identifier">It2</span><span class="special">>::</span><span class="identifier">type</span><span class="special">()</span></code> </p> </td> </tr> <tr> <td> <p> <code class="computeroutput"><span class="identifier">iterator</span><span class="special">::</span><span class="keyword">template</span> <span class="identifier">key_of</span><span class="special"><</span><span class="identifier">It</span><span class="special">>::</span><span class="identifier">type</span></code> </p> </td> <td> <p> The key type associated with the element from <code class="computeroutput"><span class="identifier">It</span></code> </p> </td> <td> <p> None </p> </td> </tr> <tr> <td> <p> <code class="computeroutput"><span class="identifier">iterator</span><span class="special">::</span><span class="keyword">template</span> <span class="identifier">value_of_data</span><span class="special"><</span><span class="identifier">It</span><span class="special">>::</span><span class="identifier">type</span></code> </p> </td> <td> <p> The type of the data property associated with the element from <code class="computeroutput"><span class="identifier">It</span></code> </p> </td> <td> <p> None </p> </td> </tr> <tr> <td> <p> <code class="computeroutput"><span class="identifier">iterator</span><span class="special">::</span><span class="keyword">template</span> <span class="identifier">deref_data</span><span class="special"><</span><span class="identifier">It</span><span class="special">>::</span><span class="identifier">type</span></code> </p> </td> <td> <p> The type that will be returned by dereferencing the data property of the element from <code class="computeroutput"><span class="identifier">It</span></code> </p> </td> <td> <p> None </p> </td> </tr> <tr> <td> <p> <code class="computeroutput"><span class="identifier">iterator</span><span class="special">::</span><span class="keyword">template</span> <span class="identifier">deref_data</span><span class="special"><</span><span class="identifier">It</span><span class="special">>::</span><span class="identifier">call</span><span class="special">(</span><span class="identifier">it</span><span class="special">)</span></code> </p> </td> <td> <p> Deferences the data property associated with the element referenced by <code class="computeroutput"><span class="identifier">it</span></code> </p> </td> <td> <p> None </p> </td> </tr> </tbody> </table></div> </div> <br class="table-break"><a name="fusion.extension.iterator_facade.header"></a><h5> <a name="id1104130"></a> <a class="link" href="iterator_facade.html#fusion.extension.iterator_facade.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">iterator</span><span class="special">/</span><span class="identifier">iterator_facade</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">iterator_facade</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> </pre> <a name="fusion.extension.iterator_facade.example"></a><h5> <a name="id1104238"></a> <a class="link" href="iterator_facade.html#fusion.extension.iterator_facade.example">Example</a> </h5> <p> A full working example using <a class="link" href="iterator_facade.html" title="Iterator Facade"><code class="computeroutput"><span class="identifier">iterator_facade</span></code></a> is provided in triple.cpp in the extension examples. </p> </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>) </p> </div></td> </tr></table> <hr> <div class="spirit-nav"> <a accesskey="p" href="sequence_facade.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../extension.html"><img src="../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="../functional.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> </div> </body> </html>