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[SVN r12400]
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Vesa Karvonen
2002-01-21 19:21:24 +00:00
parent e1af246b06
commit e562e2478b
1 changed files with 14 additions and 1 deletions
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15
include/boost/preprocessor/for.hpp
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@ -48,7 +48,20 @@ BOOST_PP_FOR##R() directly. For each macro implemented using BOOST_PP_FOR(),
there is a version of the macro, distinguished by the _R suffix, that accepts there is a version of the macro, distinguished by the _R suffix, that accepts
an additional recursion depth as the first parameter. This technique is an additional recursion depth as the first parameter. This technique is
necessary to avoid recursively expanding the same macro again, which is not necessary to avoid recursively expanding the same macro again, which is not
permitted by the C/C++ preprocessor. permitted by the C++ preprocessor.
<H3>BOOST_PP_REPEAT() vs BOOST_PP_FOR()</H3>
BOOST_PP_FOR() is a generalization of BOOST_PP_REPEAT(). This means that
BOOST_PP_REPEAT() can be implemented using BOOST_PP_FOR(). Unfortunately,
BOOST_PP_FOR() is slower than BOOST_PP_REPEAT(). In addition,
BOOST_PP_REPEAT() was introduced earlier, is generally easier to use, and is
still quite useful on its own.
<H3>2D and 3D repetition</H3>
BOOST_PP_FOR() can be used for multidimensional repetition simply by invoking
BOOST_PP_FOR##R() directly.
*/ */
#define BOOST_PP_FOR(X,C,F,I) BOOST_PP_FOR0(X,C,F,I) #define BOOST_PP_FOR(X,C,F,I) BOOST_PP_FOR0(X,C,F,I)