]>
Commit | Line | Data |
---|---|---|
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 |