mirror of
https://github.com/boostorg/preprocessor.git
synced 2025-07-05 00:36:31 +02:00
92 lines
3.7 KiB
HTML
92 lines
3.7 KiB
HTML
<html>
|
|
<head>
|
|
<title>BOOST_PP_REPEAT_FROM_TO</title>
|
|
<link rel="stylesheet" type="text/css" href="../styles.css">
|
|
</head>
|
|
<body>
|
|
<div style="margin-left: 0px;">
|
|
The <b>BOOST_PP_REPEAT_FROM_TO</b> macro represents a fast horizontal repetition construct.
|
|
</div>
|
|
<h4>Usage</h4>
|
|
<div class="code">
|
|
<b>BOOST_PP_REPEAT_FROM_TO</b>(<i>first</i>, <i>last</i>, <i>macro</i>, <i>data</i>)
|
|
</div>
|
|
<h4>Arguments</h4>
|
|
<dl>
|
|
<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>
|
|
The <i>z</i> value that is passed to <i>macro</i> represents the next available repetition dimension.
|
|
Other macros that have <b>_Z</b> suffix variants internally use <b>BOOST_PP_REPEAT</b>--for example, <b>BOOST_PP_ENUM_PARAMS</b> and <b>BOOST_PP_ENUM_PARAMS_Z</b>.
|
|
Using these <b>_Z</b> versions is not strictly necessary, but passing the <i>z</i> value (that is passed to <i>macro</i>) to these macros allows them to reenter <b>BOOST_PP_REPEAT</b> with maximum efficiency.
|
|
</div>
|
|
<div>
|
|
To directly use this <i>z</i> value, rather than simply passing it to another macro, see <b>BOOST_PP_REPEAT_FROM_TO_<i>z</i></b>.
|
|
</div>
|
|
<div>
|
|
Previously, this macro could not be used recursively inside <b>BOOST_PP_REPEAT</b>.
|
|
This limitation no longer exists, as the library can automatically detect the next available repetition depth.
|
|
</div>
|
|
<div>
|
|
This macro also uses <b>BOOST_PP_WHILE</b>.
|
|
Because of this, there are also two variants of this macro for ideal reentrance into <b>BOOST_PP_WHILE</b>,
|
|
<b>BOOST_PP_REPEAT_FROM_TO_D</b> and <b>BOOST_PP_REPEAT_FROM_TO_D_<i>z</i>.
|
|
</div>
|
|
<h4>See Also</h4>
|
|
<ul>
|
|
<li><a href="limit_mag.html">BOOST_PP_LIMIT_MAG</a></li>
|
|
<li><a href="limit_repeat.html">BOOST_PP_LIMIT_REPEAT</a></li>
|
|
<li><a href="repeat_from_to_d.html">BOOST_PP_REPEAT_FROM_TO_D</a></li>
|
|
<li><a href="repeat_from_to_d_z.html">BOOST_PP_REPEAT_FROM_TO_D_<i>z</i></a></li>
|
|
<li><a href="repeat_from_to_z.html">BOOST_PP_REPEAT_FROM_TO_<i>z</i></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/cat.html">boost/preprocessor/cat.hpp</a>>
|
|
#include <<a href="../headers/repetition/repeat_from_to.html">boost/preprocessor/repetition/repeat_from_to.hpp</a>>
|
|
|
|
#define DECL(z, n, text) <a href="cat.html">BOOST_PP_CAT</a>(text, n) = n;
|
|
|
|
<a href="repeat_from_to.html">BOOST_PP_REPEAT_FROM_TO</a>(5, 10, DECL, int x)
|
|
/*
|
|
expands to:
|
|
int x5 = 5; int x6 = 6; int x7 = 7;
|
|
int x8 = 8; int x9 = 9;
|
|
*/
|
|
</pre></div>
|
|
</body>
|
|
</html>
|