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<html>
<head>
<title>BOOST_PP_LIST_TRANSFORM</title>
<link rel="stylesheet" type="text/css" href="../styles.css">
<script language="javascript" type="text/javascript" src="../scripts.js"></script>
</head>
<body onload="init('sample');">
<div style="margin-left: 0px;">
The <b>BOOST_PP_LIST_TRANSFORM</b> macro transforms each element in a <i>list</i> according to a supplied transformation.
</div>
<h4>Usage</h4>
<div class="code">
<b>BOOST_PP_LIST_TRANSFORM</b>(<i>op</i>, <i>data</i>, <i>list</i>)
</div>
<h4>Arguments</h4>
<dl>
<dt>op</dt>
<dd>
A ternary predicate of the form <i>op</i>(<i>d</i>, <i>data</i>, <i>elem</i>).&nbsp;
This transformation is expanded by <b>BOOST_PP_LIST_TRANSFORM</b> for each element in <i>list</i> with the next available <b>BOOST_PP_WHILE</b> iteration,
the auxiliary <i>data</i>, and the current element in <i>list</i>.&nbsp;
</dd>
<dt>data</dt>
<dd>
Auxiliary data passed to <i>pred</i>.
</dd>
<dt>list</dt>
<dd>
The <i>list</i> to be transformed.
</dd>
</dl>
<h4>Remarks</h4>
<div>
This macro expands <i>op</i> for each element in <i>list</i>.&nbsp;
It builds a new <i>list</i> out of the results of each call.&nbsp;
If, for example, <i>list</i> is (<i>a</i>, (<i>b</i>, (<i>c</i>, <b>BOOST_PP_NIL</b>))),
this macro expands to...
<div>
(<i>op</i>(<i>d</i>, <i>data</i>, <i>a</i>), (<i>op</i>(<i>d</i>, <i>data</i>, <i>b</i>), (<i>op</i>(<i>d</i>, <i>data</i>, <i>c</i>), <b>BOOST_PP_NIL</b>)))
</div>
</div>
<div>
Previously, this macro could not be used inside <b>BOOST_PP_WHILE</b>.&nbsp;
There is no longer any such restriction.&nbsp;
It is more efficient, however, to use <b>BOOST_PP_LIST_TRANSFORM_D</b> in such a situation.
</div>
<h4>See Also</h4>
<ul>
<li><a href="list_transform_d.html">BOOST_PP_LIST_TRANSFORM_D</a></li>
</ul>
<h4>Requirements</h4>
<div>
<b>Header:</b> &nbsp;<a href="../headers/list/transform.hpp.html">&lt;boost/preprocessor/list/transform.hpp&gt;</a>
</div>
<h4><a class="local" onclick="toggle('sample');" onmouseover="change(this);" onmouseout="revert(this);">Sample Code</a></h4>
<div id="sample"><pre>
#include &lt;boost/preprocessor/arithmetic/dec.hpp&gt;
#include &lt;boost/preprocessor/list/transform.hpp&gt;
#define LIST (1, (3, (2, (5, BOOST_PP_NIL))))
#define OP(d, data, elem) BOOST_PP_DEC(elem)
BOOST_PP_LIST_TRANSFORM(OP, 3, LIST) // expands to(0, (2, (1, (4, BOOST_PP_NIL))))
<pre></div>
</body>
</html>