mirror of
https://github.com/boostorg/preprocessor.git
synced 2025-07-05 00:36:31 +02:00
95 lines
3.0 KiB
HTML
95 lines
3.0 KiB
HTML
<html>
|
|
<head>
|
|
<title>BOOST_PP_REPEAT_FROM_TO_z</title>
|
|
<link rel="stylesheet" type="text/css" href="../styles.css">
|
|
</head>
|
|
<body>
|
|
<div style="margin-left: 0px;">
|
|
The <b>BOOST_PP_REPEAT_FROM_TO_<i>z</i></b> macro represents a reentry into the <b>BOOST_PP_REPEAT_FROM_TO</b> repetition construct.
|
|
</div>
|
|
<h4>Usage</h4>
|
|
<div class="code">
|
|
<b>BOOST_PP_REPEAT_FROM_TO_</b> ## <i>z</i>(<i>first</i>, <i>last</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>first</dt>
|
|
<dd>
|
|
The lower bound of the repetition.
|
|
Valid values range from <i>0</i> to <b>BOOST_PP_LIMIT_MAG</b>.
|
|
</dd>
|
|
<dt>last</dt>
|
|
<dd>
|
|
The upper bound of the repetition.
|
|
Valid values range from <i>0</i> to <b>BOOST_PP_LIMIT_MAG</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>first</i>, <i>data</i>) <i>macro</i>(<i>z</i>, <i>first</i> + <i>1</i>, <i>data</i>) ... <i>macro</i>(<i>z</i>, <i>last</i> - <i>1</i>, <i>data</i>)
|
|
</div>
|
|
</div>
|
|
<div>
|
|
The number of repetitions (i.e. <i>last</i> - <i>first</i>) must not exceed <b>BOOST_PP_LIMIT_REPEAT</b>.
|
|
</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_FROM_TO_</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_from_to.html"><boost/preprocessor/repetition/repeat_from_to.hpp></a>
|
|
</div>
|
|
<h4>Sample Code</h4>
|
|
<div><pre>
|
|
#include <<a href="../headers/repetition/repeat_from_to.html">boost/preprocessor/repetition/repeat_from_to.hpp</a>>
|
|
|
|
#define TEXT(z, n, data) n data
|
|
|
|
#define MACRO(z, n, data) \
|
|
( \
|
|
<a href="repeat_from_to_z.html">BOOST_PP_REPEAT_FROM_TO_</a> ## z( \
|
|
1, 4, \
|
|
TEXT, xyz \
|
|
) \
|
|
) \
|
|
/**/
|
|
|
|
<a href="repeat.html">BOOST_PP_REPEAT</a>(3, MACRO, _)
|
|
/*
|
|
expands to:
|
|
(1 xyz 2 xyz 3 xyz)
|
|
(1 xyz 2 xyz 3 xyz)
|
|
(1 xyz 2 xyz 3 xyz)
|
|
*/
|
|
</pre></div>
|
|
</body>
|
|
</html>
|