projects / ceph.git / blame
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|---|---|---|
| 7c673cae FG |
1 | <html> |
| 2 | <head> | |
| 3 | <title>BOOST_PP_LIST_FOR_EACH_PRODUCT</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_LIST_FOR_EACH_PRODUCT</b> macro repeats a macro for each cartesian product of several <i>lists</i>. | |
| 9 | </div> | |
| 10 | <h4>Usage</h4> | |
| 11 | <div class="code"> | |
| 12 | <b>BOOST_PP_LIST_FOR_EACH_PRODUCT</b>(<i>macro</i>, <i>size</i>, <i>tuple</i>) | |
| 13 | </div> | |
| 14 | <h4>Arguments</h4> | |
| 15 | <dl> | |
| 16 | <dt>macro</dt> | |
| 17 | <dd> | |
| 18 | The binary macro of the form <i>macro</i>(<i>r</i>, <i>product</i>). | |
| 19 | This macro is expanded by <b>BOOST_PP_FOR_EACH_PRODUCT</b> with each cartesian product in <i>tuple</i>. | |
| 20 | It is expanded with the next available <b>BOOST_PP_FOR</b> repetition and a <i>tuple</i> containing a cartesian product. | |
| 21 | This <i>tuple</i> will have <i>size</i> elements. | |
| 22 | </dd> | |
| 23 | <dt>size</dt> | |
| 24 | <dd> | |
| 25 | The size of <i>tuple</i>. | |
| 26 | </dd> | |
| 27 | <dt>tuple</dt> | |
| 28 | <dd> | |
| 29 | A <i>tuple</i> of <i>lists</i> from which cartesian products are obtained. | |
| 30 | </dd> | |
| 31 | </dl> | |
| 32 | <h4>Remarks</h4> | |
| 33 | <div> | |
| 34 | This macro is a repetition construct. | |
| 35 | If two <i>lists</i> are (<i>a</i>, (<i>b</i>, (<i>c</i>, <b>BOOST_PP_NIL</b>))) and (<i>x</i>, (<i>y</i>, (<i>z</i>, <b>BOOST_PP_NIL</b>))), | |
| 36 | this macro will produce the following sequence: | |
| 37 | <div> | |
| 38 | <i>macro</i>(<i>r</i>, (<i>a</i>, <i>x</i>)) | |
| 39 | <i>macro</i>(<i>r</i>, (<i>a</i>, <i>y</i>)) | |
| 40 | <i>macro</i>(<i>r</i>, (<i>a</i>, <i>z</i>))<br> | |
| 41 | <i>macro</i>(<i>r</i>, (<i>b</i>, <i>x</i>)) | |
| 42 | <i>macro</i>(<i>r</i>, (<i>b</i>, <i>y</i>)) | |
| 43 | <i>macro</i>(<i>r</i>, (<i>b</i>, <i>z</i>))<br> | |
| 44 | <i>macro</i>(<i>r</i>, (<i>c</i>, <i>x</i>)) | |
| 45 | <i>macro</i>(<i>r</i>, (<i>c</i>, <i>y</i>)) | |
| 46 | <i>macro</i>(<i>r</i>, (<i>c</i>, <i>z</i>)) | |
| 47 | </div> | |
| 48 | </div> | |
| 49 | <div> | |
| 50 | Previously, this macro could not be used inside <b>BOOST_PP_FOR</b>. | |
| 51 | There is no longer any such restriction. | |
| 52 | It is more efficient, however, to use <b>BOOST_PP_LIST_FOR_EACH_PRODUCT_R</b> in such a situation. | |
| 53 | </div> | |
| 54 | <h4>See Also</h4> | |
| 55 | <ul> | |
| 56 | <li><a href="list_for_each_product_r.html">BOOST_PP_LIST_FOR_EACH_PRODUCT_R</a></li> | |
| 57 | </ul> | |
| 58 | <h4>Requirements</h4> | |
| 59 | <div> | |
| 60 | <b>Header:</b> <a href="../headers/list/for_each_product.html"><boost/preprocessor/list/for_each_product.hpp></a> | |
| 61 | </div> | |
| 62 | <h4>Sample Code</h4> | |
| 63 | <div><pre> | |
| 64 | #include <<a href="../headers/list/for_each_product.html">boost/preprocessor/list/for_each_product.hpp</a>> | |
| 65 | ||
| 66 | #define L1 (a, (b, (c, <a href="nil.html">BOOST_PP_NIL</a>))) | |
| 67 | #define L2 (x, (y, (z, <a href="nil.html">BOOST_PP_NIL</a>))) | |
| 68 | ||
| 69 | #define MACRO(r, product) product | |
| 70 | ||
| 71 | <a href="list_for_each_product.html">BOOST_PP_LIST_FOR_EACH_PRODUCT</a>(MACRO, 2, (L1, L2)) | |
| 72 | // expands to (a, x) (a, y) (a, z) (b, x) (b, y) (b, z) (c, x) (c, y) (c, z) | |
| 73 | </pre></div> | |
| 74 | <hr size="1"> | |
| 75 | <div style="margin-left: 0px;"> | |
| 76 |