mirror of
https://github.com/boostorg/preprocessor.git
synced 2025-07-05 00:36:31 +02:00
90 lines
3.0 KiB
HTML
90 lines
3.0 KiB
HTML
<html>
|
|
<head>
|
|
<title>BOOST_PP_REPEAT_z</title>
|
|
<link rel="stylesheet" type="text/css" href="../styles.css">
|
|
</head>
|
|
<body>
|
|
<div style="margin-left: 0px;">
|
|
The <b>BOOST_PP_REPEAT_<i>z</i></b> macro represents a reentry into the <b>BOOST_PP_REPEAT</b> repetition construct.
|
|
</div>
|
|
<h4>Usage</h4>
|
|
<div class="code">
|
|
<b>BOOST_PP_REPEAT_</b> ## <i>z</i>(<i>count</i>, <i>macro</i>, <i>data</i>)
|
|
</div>
|
|
<h4>Arguments</h4>
|
|
<dl>
|
|
<dt>z</dt>
|
|
<dd>
|
|
The next available <b>BOOST_PP_REPEAT</b> dimension.
|
|
</dd>
|
|
<dt>count</dt>
|
|
<dd>
|
|
The number of repetitious calls to <i>macro</i>.
|
|
Valid values range from <i>0</i> to <b>BOOST_PP_LIMIT_REPEAT</b>.
|
|
</dd>
|
|
<dt>macro</dt>
|
|
<dd>
|
|
A ternary operation of the form <i>macro</i>(<i>z</i>, <i>n</i>, <i>data</i>).
|
|
This macro is expanded by <b>BOOST_PP_REPEAT</b> with the next available repetition depth,
|
|
the current repetition number, and the auxiliary <i>data</i> argument.
|
|
</dd>
|
|
<dt>data</dt>
|
|
<dd>
|
|
Auxiliary data passed to <i>macro</i>.
|
|
</dd>
|
|
</dl>
|
|
<h4>Remarks</h4>
|
|
<div>
|
|
This macro expands to the sequence:
|
|
<div>
|
|
<i>macro</i>(<i>z</i>, <i>0</i>, <i>data</i>) <i>macro</i>(<i>z</i>, <i>1</i>, <i>data</i>) ... <i>macro</i>(<i>z</i>, <i>count</i> - <i>1</i>, <i>data</i>)
|
|
</div>
|
|
</div>
|
|
<div>
|
|
At certain times, it may be necessary to perform the concatenation with <b>BOOST_PP_CAT</b> rather than the preprocessor token-pasting operator.
|
|
This happens when the <i>z</i> value is a macro invocation itself.
|
|
It needs a delay to allow it to expand.
|
|
The syntax in such a scenario becomes:
|
|
<div>
|
|
<b>BOOST_PP_CAT</b>(<b>BOOST_PP_REPEAT_</b>, <i>z</i>)(<i>count</i>, <i>macro</i>, <i>data</i>)
|
|
</div>
|
|
</div>
|
|
<h4>See Also</h4>
|
|
<ul>
|
|
<li><a href="cat.html">BOOST_PP_CAT</a></li>
|
|
<li><a href="limit_repeat.html">BOOST_PP_LIMIT_REPEAT</a></li>
|
|
<li><a href="repeat.html">BOOST_PP_REPEAT</a></li>
|
|
</ul>
|
|
<h4>Requirements</h4>
|
|
<div>
|
|
<b>Header:</b> <a href="../headers/repetition/repeat.html"><boost/preprocessor/repetition/repeat.hpp></a>
|
|
</div>
|
|
<h4>Sample Code</h4>
|
|
<div><pre>
|
|
#include <<a href="../headers/arithmetic/inc.html">boost/preprocessor/arithmetic/inc.hpp</a>>
|
|
#include <<a href="../headers/punctuation/comma_if.html">boost/preprocessor/punctuation/comma_if.hpp</a>>
|
|
#include <<a href="../headers/repetition/repeat.html">boost/preprocessor/repetition/repeat.hpp</a>>
|
|
|
|
#define TEXT(z, n, text) <a href="comma_if.html">BOOST_PP_COMMA_IF</a>(n) text
|
|
|
|
#define TEMPLATE(z, n, _) \
|
|
<a href="comma_if.html">BOOST_PP_COMMA_IF</a>(n) \
|
|
template< \
|
|
<a href="repeat_z.html">BOOST_PP_REPEAT_</a> ## z( \
|
|
<a href="inc.html">BOOST_PP_INC</a>(n), \
|
|
TEXT, class \
|
|
) \
|
|
> class T ## n \
|
|
/**/
|
|
|
|
<a href="repeat.html">BOOST_PP_REPEAT</a>(3, TEMPLATE, nil)
|
|
/*
|
|
expands to:
|
|
template<class> class T0,
|
|
template<class, class> class T1,
|
|
template<class, class, class> class T2
|
|
*/
|
|
</pre></div>
|
|
</body>
|
|
</html>
|