| Brian Silverman | f27e085 | 2018-08-04 23:56:45 -0700 | [diff] [blame^] | 1 | <html> |
| 2 | <head> |
| 3 | <title>BOOST_PP_REPEAT_FROM_TO</title> |
| 4 | <link rel="stylesheet" type="text/css" href="../styles.css"> |
| 5 | </head> |
| 6 | <body> |
| 7 | <div style="margin-left: 0px;"> |
| 8 | The <b>BOOST_PP_REPEAT_FROM_TO</b> macro represents a fast horizontal repetition construct. |
| 9 | </div> |
| 10 | <h4>Usage</h4> |
| 11 | <div class="code"> |
| 12 | <b>BOOST_PP_REPEAT_FROM_TO</b>(<i>first</i>, <i>last</i>, <i>macro</i>, <i>data</i>) |
| 13 | </div> |
| 14 | <h4>Arguments</h4> |
| 15 | <dl> |
| 16 | <dt>first</dt> |
| 17 | <dd> |
| 18 | The lower bound of the repetition. |
| 19 | Valid values range from <i>0</i> to <b>BOOST_PP_LIMIT_MAG</b>. |
| 20 | </dd> |
| 21 | <dt>last</dt> |
| 22 | <dd> |
| 23 | The upper bound of the repetition. |
| 24 | Valid values range from <i>0</i> to <b>BOOST_PP_LIMIT_MAG</b>. |
| 25 | </dd> |
| 26 | <dt>macro</dt> |
| 27 | <dd> |
| 28 | A ternary operation of the form <i>macro</i>(<i>z</i>, <i>n</i>, <i>data</i>). |
| 29 | This macro is expanded by <b>BOOST_PP_REPEAT</b> with the next available repetition depth, |
| 30 | the current repetition number, and the auxiliary <i>data</i> argument. |
| 31 | </dd> |
| 32 | <dt>data</dt> |
| 33 | <dd> |
| 34 | Auxiliary data passed to <i>macro</i>. |
| 35 | </dd> |
| 36 | </dl> |
| 37 | <h4>Remarks</h4> |
| 38 | <div> |
| 39 | This macro expands to the sequence: |
| 40 | <div> |
| 41 | <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>) |
| 42 | </div> |
| 43 | </div> |
| 44 | <div> |
| 45 | The number of repetitions (i.e. <i>last</i> - <i>first</i>) must not exceed <b>BOOST_PP_LIMIT_REPEAT</b>. |
| 46 | </div> |
| 47 | <div> |
| 48 | The <i>z</i> value that is passed to <i>macro</i> represents the next available repetition dimension. |
| 49 | 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>. |
| 50 | 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. |
| 51 | </div> |
| 52 | <div> |
| 53 | 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>. |
| 54 | </div> |
| 55 | <div> |
| 56 | Previously, this macro could not be used recursively inside <b>BOOST_PP_REPEAT</b>. |
| 57 | This limitation no longer exists, as the library can automatically detect the next available repetition depth. |
| 58 | </div> |
| 59 | <div> |
| 60 | This macro also uses <b>BOOST_PP_WHILE</b>. |
| 61 | Because of this, there are also two variants of this macro for ideal reentrance into <b>BOOST_PP_WHILE</b>, |
| 62 | <b>BOOST_PP_REPEAT_FROM_TO_D</b> and <b>BOOST_PP_REPEAT_FROM_TO_D_<i>z</i>. |
| 63 | </div> |
| 64 | <h4>See Also</h4> |
| 65 | <ul> |
| 66 | <li><a href="limit_mag.html">BOOST_PP_LIMIT_MAG</a></li> |
| 67 | <li><a href="limit_repeat.html">BOOST_PP_LIMIT_REPEAT</a></li> |
| 68 | <li><a href="repeat_from_to_d.html">BOOST_PP_REPEAT_FROM_TO_D</a></li> |
| 69 | <li><a href="repeat_from_to_d_z.html">BOOST_PP_REPEAT_FROM_TO_D_<i>z</i></a></li> |
| 70 | <li><a href="repeat_from_to_z.html">BOOST_PP_REPEAT_FROM_TO_<i>z</i></a></li> |
| 71 | </ul> |
| 72 | <h4>Requirements</h4> |
| 73 | <div> |
| 74 | <b>Header:</b> <a href="../headers/repetition/repeat_from_to.html"><boost/preprocessor/repetition/repeat_from_to.hpp></a> |
| 75 | </div> |
| 76 | <h4>Sample Code</h4> |
| 77 | <div><pre> |
| 78 | #include <<a href="../headers/cat.html">boost/preprocessor/cat.hpp</a>> |
| 79 | #include <<a href="../headers/repetition/repeat_from_to.html">boost/preprocessor/repetition/repeat_from_to.hpp</a>> |
| 80 | |
| 81 | #define DECL(z, n, text) <a href="cat.html">BOOST_PP_CAT</a>(text, n) = n; |
| 82 | |
| 83 | <a href="repeat_from_to.html">BOOST_PP_REPEAT_FROM_TO</a>(5, 10, DECL, int x) |
| 84 | /* |
| 85 | expands to: |
| 86 | int x5 = 5; int x6 = 6; int x7 = 7; |
| 87 | int x8 = 8; int x9 = 9; |
| 88 | */ |
| 89 | </pre></div> |
| 90 | <hr size="1"> |
| 91 | <div style="margin-left: 0px;"> |
| 92 | <i>© Copyright <a href="http://www.housemarque.com" target="_top">Housemarque Oy</a> 2002</i> |
| 93 | </br><i>© Copyright Paul Mensonides 2002</i> |
| 94 | </div> |
| 95 | <div style="margin-left: 0px;"> |
| 96 | <p><small>Distributed under the Boost Software License, Version 1.0. (See |
| 97 | accompanying file <a href="../../../../LICENSE_1_0.txt">LICENSE_1_0.txt</a> or |
| 98 | copy at <a href= |
| 99 | "http://www.boost.org/LICENSE_1_0.txt">www.boost.org/LICENSE_1_0.txt</a>)</small></p> |
| 100 | </div> |
| 101 | </body> |
| 102 | </html> |