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updates functional module: only two unfused variants, now

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[SVN r51381]
This commit is contained in:
Tobias Schwinger
2009-02-22 06:27:12 +00:00
parent 2fdfd41b17
commit aaf89a67a6
263 changed files with 5823 additions and 7742 deletions
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doc/html/fusion/algorithm.html
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<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">
<meta name="generator" content="DocBook XSL Stylesheets V1.68.1">
<link rel="start" href="../index.html" title="Chapter<65>1.<2E>Fusion 2.0">
<link rel="up" href="../index.html" title="Chapter<65>1.<2E>Fusion 2.0">
<link rel="prev" href="adapted/adapt_assoc.html" title=" BOOST_FUSION_ADAPT_ASSOC_STRUCT">
@ -43,7 +43,7 @@
</dl></dd>
</dl></div>
<a name="fusion.algorithm.lazy_evaluation"></a><h3>
<a name="id578702"></a>
<a name="id1147994"></a>
<a href="algorithm.html#fusion.algorithm.lazy_evaluation">Lazy Evaluation</a>
</h3>
<p>
@ -57,43 +57,42 @@
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
algorithms instead. For example, the <a href="algorithm/transformation/functions/transform.html" title="transform"><code class="computeroutput"><span class="identifier">transform</span></code></a> algorithm does not actually
return a transformed version of the original sequence. <a href="algorithm/transformation/functions/transform.html" title="transform"><code class="computeroutput"><span class="identifier">transform</span></code></a> returns a <a href="view/transform_view.html" title="transform_view"><code class="computeroutput"><span class="identifier">transform_view</span></code></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>
the <a href="view/transform_view.html" title="transform_view"><code class="computeroutput"><span class="identifier">transform_view</span></code></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="id578849"></a>
<a name="id1148125"></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
as <a href="algorithm/transformation/functions/push_back.html" title="push_back"><code class="computeroutput"><span class="identifier">push_back</span></code></a> to be totally generic. In
Fusion, <a href="algorithm/transformation/functions/push_back.html" title="push_back"><code class="computeroutput"><span class="identifier">push_back</span></code></a> is actually a generic algorithm
that works on all sequences. Given an input sequence <code class="computeroutput"><span class="identifier">s</span></code>
and a value <code class="computeroutput"><span class="identifier">x</span></code>, Fusion's <a href="algorithm/transformation/functions/push_back.html" title="push_back"><code class="computeroutput"><span class="identifier">push_back</span></code></a> algorithm simply returns
a <a href="view/joint_view.html" title="joint_view"><code class="computeroutput"><span class="identifier">joint_view</span></code></a>:
a view that holds a reference to the original sequence <code class="computeroutput"><span class="identifier">s</span></code>
and the value <code class="computeroutput"><span class="identifier">x</span></code>. 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,
result of a sequence extending operation like <a href="algorithm/transformation/functions/push_back.html" title="push_back"><code class="computeroutput"><span class="identifier">push_back</span></code></a> does not retain the properties
of the original sequence such as associativity of <a href="container/set.html" title="set"><code class="computeroutput"><span class="identifier">set</span></code></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="id579083"></a>
<a name="id1148334"></a>
<a href="algorithm.html#fusion.algorithm.header">Header</a>
</h3>
<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">algorithm</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
<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">algorithm</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">include</span><span class="special">/</span><span class="identifier">algorithm</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
</pre>
</div>