projects / ceph.git / blame
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|---|---|---|
| 7c673cae FG |
1 | <html> |
| 2 | <head> | |
| 3 | <title>BOOST_PP_REPEAT_FROM_TO_z</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_<i>z</i></b> macro represents a reentry into the <b>BOOST_PP_REPEAT_FROM_TO</b> repetition construct. | |
| 9 | </div> | |
| 10 | <h4>Usage</h4> | |
| 11 | <div class="code"> | |
| 12 | <b>BOOST_PP_REPEAT_FROM_TO_</b> ## <i>z</i>(<i>first</i>, <i>last</i>, <i>macro</i>, <i>data</i>) | |
| 13 | </div> | |
| 14 | <h4>Arguments</h4> | |
| 15 | <dl> | |
| 16 | <dt>z</dt> | |
| 17 | <dd> | |
| 18 | The next available <b>BOOST_PP_REPEAT</b> dimension. | |
| 19 | </dd> | |
| 20 | <dt>first</dt> | |
| 21 | <dd> | |
| 22 | The lower bound of the repetition. | |
| 23 | Valid values range from <i>0</i> to <b>BOOST_PP_LIMIT_MAG</b>. | |
| 24 | </dd> | |
| 25 | <dt>last</dt> | |
| 26 | <dd> | |
| 27 | The upper bound of the repetition. | |
| 28 | Valid values range from <i>0</i> to <b>BOOST_PP_LIMIT_MAG</b>. | |
| 29 | </dd> | |
| 30 | <dt>macro</dt> | |
| 31 | <dd> | |
| 32 | A ternary operation of the form <i>macro</i>(<i>z</i>, <i>n</i>, <i>data</i>). | |
| 33 | This macro is expanded by <b>BOOST_PP_REPEAT</b> with the next available repetition depth, | |
| 34 | the current repetition number, and the auxiliary <i>data</i> argument. | |
| 35 | </dd> | |
| 36 | <dt>data</dt> | |
| 37 | <dd> | |
| 38 | Auxiliary data passed to <i>macro</i>. | |
| 39 | </dd> | |
| 40 | </dl> | |
| 41 | <h4>Remarks</h4> | |
| 42 | <div> | |
| 43 | This macro expands to the sequence: | |
| 44 | <div> | |
| 45 | <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>) | |
| 46 | </div> | |
| 47 | </div> | |
| 48 | <div> | |
| 49 | The number of repetitions (i.e. <i>last</i> - <i>first</i>) must not exceed <b>BOOST_PP_LIMIT_REPEAT</b>. | |
| 50 | </div> | |
| 51 | <div> | |
| 52 | At certain times, it may be necessary to perform the concatenation with <b>BOOST_PP_CAT</b> rather than the preprocessor token-pasting operator. | |
| 53 | This happens when the <i>z</i> value is a macro invocation itself. | |
| 54 | It needs a delay to allow it to expand. | |
| 55 | The syntax in such a scenario becomes: | |
| 56 | <div> | |
| 57 | <b>BOOST_PP_CAT</b>(<b>BOOST_PP_REPEAT_FROM_TO_</b>, <i>z</i>)(<i>count</i>, <i>macro</i>, <i>data</i>). | |
| 58 | </div> | |
| 59 | </div> | |
| 60 | <h4>See Also</h4> | |
| 61 | <ul> | |
| 62 | <li><a href="cat.html">BOOST_PP_CAT</a></li> | |
| 63 | <li><a href="limit_repeat.html">BOOST_PP_LIMIT_REPEAT</a></li> | |
| 64 | <li><a href="repeat.html">BOOST_PP_REPEAT</a></li> | |
| 65 | </ul> | |
| 66 | <h4>Requirements</h4> | |
| 67 | <div> | |
| 68 | <b>Header:</b> <a href="../headers/repetition/repeat_from_to.html"><boost/preprocessor/repetition/repeat_from_to.hpp></a> | |
| 69 | </div> | |
| 70 | <h4>Sample Code</h4> | |
| 71 | <div><pre> | |
| 72 | #include <<a href="../headers/repetition/repeat_from_to.html">boost/preprocessor/repetition/repeat_from_to.hpp</a>> | |
| 73 | ||
| 74 | #define TEXT(z, n, data) n data | |
| 75 | ||
| 76 | #define MACRO(z, n, data) \ | |
| 77 | ( \ | |
| 78 | <a href="repeat_from_to_z.html">BOOST_PP_REPEAT_FROM_TO_</a> ## z( \ | |
| 79 | 1, 4, \ | |
| 80 | TEXT, xyz \ | |
| 81 | ) \ | |
| 82 | ) \ | |
| 83 | /**/ | |
| 84 | ||
| 85 | <a href="repeat.html">BOOST_PP_REPEAT</a>(3, MACRO, _) | |
| 86 | /* | |
| 87 | expands to: | |
| 88 | (1 xyz 2 xyz 3 xyz) | |
| 89 | (1 xyz 2 xyz 3 xyz) | |
| 90 | (1 xyz 2 xyz 3 xyz) | |
| 91 | */ | |
| 92 | </pre></div> | |
| 93 | <hr size="1"> | |
| 94 | <div style="margin-left: 0px;"> | |
| 95 |