forked from boostorg/fusion
https://svn.boost.org/svn/boost/trunk ........ r41077 | troyer | 2007-11-13 23:00:02 -0800 (Tue, 13 Nov 2007) | 1 line Added support for std::complex to serialization ........ r41078 | joaquin | 2007-11-13 23:09:29 -0800 (Tue, 13 Nov 2007) | 1 line added missing include ........ r41079 | djowel | 2007-11-14 02:13:51 -0800 (Wed, 14 Nov 2007) | 1 line adjust to compensate for lack of <small> tag. ........ r41080 | djowel | 2007-11-14 02:17:09 -0800 (Wed, 14 Nov 2007) | 1 line refresh docs ........ r41081 | djowel | 2007-11-14 02:23:23 -0800 (Wed, 14 Nov 2007) | 1 line refresh docs ........ r41082 | djowel | 2007-11-14 02:24:21 -0800 (Wed, 14 Nov 2007) | 1 line refresh docs ........ r41083 | anthonyw | 2007-11-14 03:08:09 -0800 (Wed, 14 Nov 2007) | 1 line ignore and join all threads in group on exception ........ r41084 | anthonyw | 2007-11-14 03:56:53 -0800 (Wed, 14 Nov 2007) | 1 line interrupt and join all threads in a group if an exception is thrown during a test ........ r41086 | johnmaddock | 2007-11-14 04:14:19 -0800 (Wed, 14 Nov 2007) | 1 line Merged changes from the Sandbox to Trunk. ........ r41087 | anthonyw | 2007-11-14 04:17:41 -0800 (Wed, 14 Nov 2007) | 1 line interrupt and join all threads in a group if an exception is thrown during a test ........ r41088 | johnmaddock | 2007-11-14 04:41:32 -0800 (Wed, 14 Nov 2007) | 1 line Added WinCE workaround. ........ r41089 | johnmaddock | 2007-11-14 05:03:15 -0800 (Wed, 14 Nov 2007) | 1 line Catch exceptions thrown from thread creation. ........ r41090 | anthonyw | 2007-11-14 06:49:58 -0800 (Wed, 14 Nov 2007) | 1 line fixes for pthread implementation ........ r41091 | bemandawes | 2007-11-14 07:50:43 -0800 (Wed, 14 Nov 2007) | 1 line Replace old docs with excerpts from http://article.gmane.org/gmane.comp.lib.boost.testing/5020 ........ r41093 | eric_niebler | 2007-11-14 08:36:15 -0800 (Wed, 14 Nov 2007) | 1 line fix support for segmented iteration ........ r41094 | dave | 2007-11-14 09:37:55 -0800 (Wed, 14 Nov 2007) | 3 lines Update command-prompt instructions per http://news.gmane.org/find-root.php?message_id=%3cfhcrem%24c4%241%40ger.gmane.org%3e ........ r41095 | bemandawes | 2007-11-14 12:05:30 -0800 (Wed, 14 Nov 2007) | 1 line Bring docs more in line with reality:-) ........ r41097 | hljin | 2007-11-14 18:07:53 -0800 (Wed, 14 Nov 2007) | 1 line GIL: removed the example directory from the documentation as it is a duplication and re-directed the Doxygen documentation to a local copy (to be submitted next) ........ r41098 | hljin | 2007-11-14 18:30:13 -0800 (Wed, 14 Nov 2007) | 1 line GIL: added a local copy of the Doxygen documentation ........ r41099 | hljin | 2007-11-14 18:32:04 -0800 (Wed, 14 Nov 2007) | 1 line GIL: added a local copy of the Doxygen documentation (second batch) ........ r41100 | chris_kohlhoff | 2007-11-14 22:19:04 -0800 (Wed, 14 Nov 2007) | 6 lines Try to fix an order-of-initialisation problem with error_category references. The symptom, which only occurs in some applications, is a crash due to a dereference of a null pointer. The exact conditions under which the problem occurs are not fully understood, so this fix is probably more paranoid than necessary. ........ r41102 | jhunold | 2007-11-14 23:04:24 -0800 (Wed, 14 Nov 2007) | 1 line Suppress msvc "deprecated" warnings. ........ r41103 | johnmaddock | 2007-11-15 01:52:26 -0800 (Thu, 15 Nov 2007) | 1 line Fix some compiler warnings when building with the Intel and aCC compilers. ........ r41104 | garcia | 2007-11-15 04:50:48 -0800 (Thu, 15 Nov 2007) | 2 lines John Torjo is reviewing the X-files. ........ r41105 | hkaiser | 2007-11-15 05:27:24 -0800 (Thu, 15 Nov 2007) | 1 line Suppressed more warnings during build of Wave. ........ r41106 | bemandawes | 2007-11-15 06:36:40 -0800 (Thu, 15 Nov 2007) | 1 line GetUserDefaultUILanguage isn't present for Cygwin, so disable use ........ r41107 | bemandawes | 2007-11-15 07:20:27 -0800 (Thu, 15 Nov 2007) | 1 line Get rid of .cvsignore files ........ r41108 | eric_niebler | 2007-11-15 08:06:22 -0800 (Thu, 15 Nov 2007) | 1 line fix typo ........ r41110 | grafik | 2007-11-15 08:58:21 -0800 (Thu, 15 Nov 2007) | 1 line Fix building of multiple regression tools at once. ........ r41111 | gmelquio | 2007-11-15 09:52:31 -0800 (Thu, 15 Nov 2007) | 1 line Fixed documentation typo. ........ r41113 | grafik | 2007-11-15 10:56:43 -0800 (Thu, 15 Nov 2007) | 1 line Switch intel-win32 to use static multi thread runtime since the single thread static runtime is no longer available. (fixes #1287) ........ r41114 | andreas_huber69 | 2007-11-15 11:22:12 -0800 (Thu, 15 Nov 2007) | 1 line Added new FAQ item suggested by Chris Paulse. ........ r41116 | guwi17 | 2007-11-15 12:52:37 -0800 (Thu, 15 Nov 2007) | 4 lines This patch now lets the Sun compiler work for most of uBLAS. 'test4' is now failing. Too avoid other compilers complaining about missing return values in some functions where exceptions are thrown, code was added so an arbitatry were chosen. ........ r41117 | danmarsden | 2007-11-15 13:15:47 -0800 (Thu, 15 Nov 2007) | 1 line removing failing test on EDG compilers ........ r41118 | grafik | 2007-11-15 14:05:15 -0800 (Thu, 15 Nov 2007) | 1 line Remove redundant reference to system library. It causes double linking when used indirectly through filesystem. Which can lead to double linking incompatible variants when a specific filesystem variant is requested. ........ r41119 | grafik | 2007-11-15 14:05:22 -0800 (Thu, 15 Nov 2007) | 1 line Oops, forgot we need to use the root boost project settings when building. ........ [SVN r41141]
115 lines
9.3 KiB
HTML
115 lines
9.3 KiB
HTML
<html>
|
||
<head>
|
||
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
|
||
<title>Algorithm</title>
|
||
<link rel="stylesheet" href="../../../../../doc/html/boostbook.css" type="text/css">
|
||
<meta name="generator" content="DocBook XSL Stylesheets V1.66.1">
|
||
<link rel="start" href="../index.html" title="Chapter 1. Fusion 2.0">
|
||
<link rel="up" href="../index.html" title="Chapter 1. Fusion 2.0">
|
||
<link rel="prev" href="adapted/boost__variant.html" title="boost::variant">
|
||
<link rel="next" href="algorithm/iteration.html" title="Iteration">
|
||
</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.htm">Home</a></td>
|
||
<td align="center"><a href="../../../../libraries.htm">Libraries</a></td>
|
||
<td align="center"><a href="../../../../../people/people.htm">People</a></td>
|
||
<td align="center"><a href="../../../../../more/faq.htm">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="adapted/boost__variant.html"><img src="../../../../../doc/html/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../doc/html/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../doc/html/images/home.png" alt="Home"></a><a accesskey="n" href="algorithm/iteration.html"><img src="../../../../../doc/html/images/next.png" alt="Next"></a>
|
||
</div>
|
||
<div class="section" lang="en">
|
||
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
|
||
<a name="fusion.algorithm"></a><a href="algorithm.html" title="Algorithm">Algorithm</a></h2></div></div></div>
|
||
<div class="toc"><dl>
|
||
<dt><span class="section"><a href="algorithm/iteration.html">Iteration</a></span></dt>
|
||
<dd><dl>
|
||
<dt><span class="section"><a href="algorithm/iteration/functions.html">Functions</a></span></dt>
|
||
<dt><span class="section"><a href="algorithm/iteration/metafunctions.html">Metafunctions</a></span></dt>
|
||
</dl></dd>
|
||
<dt><span class="section"><a href="algorithm/query.html">Query</a></span></dt>
|
||
<dd><dl>
|
||
<dt><span class="section"><a href="algorithm/query/functions.html">Functions</a></span></dt>
|
||
<dt><span class="section"><a href="algorithm/query/metafunctions.html">Metafunctions</a></span></dt>
|
||
</dl></dd>
|
||
<dt><span class="section"><a href="algorithm/transformation.html">Transformation</a></span></dt>
|
||
<dd><dl>
|
||
<dt><span class="section"><a href="algorithm/transformation/functions.html">Functions</a></span></dt>
|
||
<dt><span class="section"><a href="algorithm/transformation/metafunctions.html">Metafunctions</a></span></dt>
|
||
</dl></dd>
|
||
</dl></div>
|
||
<a name="fusion.algorithm.lazy_evaluation"></a><h3>
|
||
<a name="id574778"></a>
|
||
<a href="algorithm.html#fusion.algorithm.lazy_evaluation">Lazy Evaluation</a>
|
||
</h3>
|
||
<p>
|
||
Unlike <a href="http://www.boost.org/libs/mpl/index.html" target="_top">MPL</a>, Fusion
|
||
algorithms are lazy and non sequence-type preserving. What does that mean?
|
||
It means that when you operate on a sequence through a Fusion algorithm that
|
||
returns a sequence, the sequence returned may not be of the same class as the
|
||
original. This is by design. Runtime efficiency is given a high priority. Like
|
||
<a href="http://www.boost.org/libs/mpl/index.html" target="_top">MPL</a>, and unlike
|
||
<a href="http://en.wikipedia.org/wiki/Standard_Template_Library" target="_top">STL</a>,
|
||
fusion algorithms are functional in nature such that algorithms are non mutating
|
||
(no side effects). However, due to the high cost of returning full sequences
|
||
such as vectors and lists, <span class="emphasis"><em>Views</em></span> are returned from Fusion
|
||
algorithms instead. For example, the <a href="algorithm/transformation/functions/transform.html" title="transform"><tt class="computeroutput"><span class="identifier">transform</span></tt></a> algorithm does not actually
|
||
return a transformed version of the original sequence. <a href="algorithm/transformation/functions/transform.html" title="transform"><tt class="computeroutput"><span class="identifier">transform</span></tt></a> returns a <a href="view/transform_view.html" title="transform_view"><tt class="computeroutput"><span class="identifier">transform_view</span></tt></a>. This view holds a
|
||
reference to the original sequence plus the transform function. Iteration over
|
||
the <a href="view/transform_view.html" title="transform_view"><tt class="computeroutput"><span class="identifier">transform_view</span></tt></a>
|
||
will apply the transform function over the sequence elements on demand. This
|
||
<span class="emphasis"><em>lazy</em></span> evaluation scheme allows us to chain as many algorithms
|
||
as we want without incurring a high runtime penalty.
|
||
</p>
|
||
<a name="fusion.algorithm.sequence_extension"></a><h3>
|
||
<a name="id574926"></a>
|
||
<a href="algorithm.html#fusion.algorithm.sequence_extension">Sequence Extension</a>
|
||
</h3>
|
||
<p>
|
||
The <span class="emphasis"><em>lazy</em></span> evaluation scheme where <a href="algorithm.html" title="Algorithm">Algorithms</a>
|
||
return <a href="view.html" title="View">Views</a> also allows operations such
|
||
as <a href="algorithm/transformation/functions/push_back.html" title="push_back"><tt class="computeroutput"><span class="identifier">push_back</span></tt></a> to be totally generic. In
|
||
Fusion, <a href="algorithm/transformation/functions/push_back.html" title="push_back"><tt class="computeroutput"><span class="identifier">push_back</span></tt></a> is actually a generic algorithm
|
||
that works on all sequences. Given an input sequence <tt class="computeroutput"><span class="identifier">s</span></tt>
|
||
and a value <tt class="computeroutput"><span class="identifier">x</span></tt>, Fusion's <a href="algorithm/transformation/functions/push_back.html" title="push_back"><tt class="computeroutput"><span class="identifier">push_back</span></tt></a> algorithm simply returns
|
||
a <a href="view/joint_view.html" title="joint_view"><tt class="computeroutput"><span class="identifier">joint_view</span></tt></a>:
|
||
a view that holds a reference to the original sequence <tt class="computeroutput"><span class="identifier">s</span></tt>
|
||
and the value <tt class="computeroutput"><span class="identifier">x</span></tt>. Functions
|
||
that were once sequence specific and need to be implemented N times over N
|
||
different sequences are now implemented only once. That is to say that Fusion
|
||
sequences are cheaply extensible. However, an important caveat is that the
|
||
result of a sequence extending operation like <a href="algorithm/transformation/functions/push_back.html" title="push_back"><tt class="computeroutput"><span class="identifier">push_back</span></tt></a> does not retain the properties
|
||
of the original sequence such as associativity of <a href="container/set.html" title="set"><tt class="computeroutput"><span class="identifier">set</span></tt></a>(s). To regain the original sequence,
|
||
<a href="container/conversion/functions.html" title="Functions">Conversion</a> functions
|
||
are provided. You may use one of the <a href="container/conversion/functions.html" title="Functions">Conversion</a>
|
||
functions to convert back to the original sequence type.
|
||
</p>
|
||
<a name="fusion.algorithm.header"></a><h3>
|
||
<a name="id575160"></a>
|
||
<a href="algorithm.html#fusion.algorithm.header">Header</a>
|
||
</h3>
|
||
<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">algorithm</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">algorithm</span><span class="special">.</span><span class="identifier">hpp</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>)
|
||
</p>
|
||
</div></td>
|
||
</tr></table>
|
||
<hr>
|
||
<div class="spirit-nav">
|
||
<a accesskey="p" href="adapted/boost__variant.html"><img src="../../../../../doc/html/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../doc/html/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../doc/html/images/home.png" alt="Home"></a><a accesskey="n" href="algorithm/iteration.html"><img src="../../../../../doc/html/images/next.png" alt="Next"></a>
|
||
</div>
|
||
</body>
|
||
</html>
|