BOOST_PP_REPEAT to repeat comma-containing text
Hello, I'm trying to repeat a group of actual parameters (passed to some 3d party plain-C "variadic" function). The function call looks like this: func(count, param1, param2, arr1[0], arr2[0], param1, param2, arr1[1], arr2[1], param1, param2, arr1[2], arr2[2] /* etc */); So essentially, I'd like to repeat (param1, param2, arr1[n], arr2[n]) group. What is the right way to invoke BOOST_PP_REPEAT in this case? Thanks.
Igor R писал 2014-04-08 16:25:
Hello,
I'm trying to repeat a group of actual parameters (passed to some 3d party plain-C "variadic" function). The function call looks like this:
func(count, param1, param2, arr1[0], arr2[0], param1, param2, arr1[1], arr2[1], param1, param2, arr1[2], arr2[2] /* etc */);
So essentially, I'd like to repeat (param1, param2, arr1[n], arr2[n]) group. What is the right way to invoke BOOST_PP_REPEAT in this case?
Hi, example: #include <boost/preprocessor/arithmetic/add.hpp> #include <boost/preprocessor/arithmetic/sub.hpp> #include <boost/preprocessor/repetition/repeat.hpp> #define PP_PROC(unused1, idx, from) \ param1, param2, arr1[BOOST_PP_ADD(from, idx)], arr2[BOOST_PP_ADD(from, idx)], #define MY_REPEAT(from, to) \ BOOST_PP_REPEAT( \ BOOST_PP_SUB(to, from) \ ,PP_PROC \ ,from \ ) /* example */ MY_REPEAT(1, 3); MY_REPEAT(9, 15); output: param1, param2, arr1[1], arr2[1], param1, param2, arr1[2], arr2[2],; param1, param2, arr1[9], arr2[9], param1, param2, arr1[10], arr2[10], param1, param2, arr1[11], arr2[11], param1, param2, arr1[12], arr2[12], param1, param2, arr1[13], arr2[13], param1, param2, arr1[14], arr2[14],; -- Regards, niXman ___________________________________________________ Dual-target(32 & 64-bit) MinGW-W64 compilers for 32 and 64-bit Windows: http://sourceforge.net/projects/mingw-w64/ ___________________________________________________ Another online IDE: http://liveworkspace.org/
example:
#include <boost/preprocessor/arithmetic/add.hpp> #include <boost/preprocessor/arithmetic/sub.hpp> #include <boost/preprocessor/repetition/repeat.hpp>
#define PP_PROC(unused1, idx, from) \ param1, param2, arr1[BOOST_PP_ADD(from, idx)], arr2[BOOST_PP_ADD(from, idx)],
#define MY_REPEAT(from, to) \ BOOST_PP_REPEAT( \ BOOST_PP_SUB(to, from) \ ,PP_PROC \ ,from \ )
Great, thanks!
I'm trying to repeat a group of actual parameters (passed to some 3d party plain-C "variadic" function). The function call looks like this:
func(count, param1, param2, arr1[0], arr2[0], param1, param2, arr1[1], arr2[1], param1, param2, arr1[2], arr2[2] /* etc */);
So essentially, I'd like to repeat (param1, param2, arr1[n], arr2[n]) group. What is the right way to invoke BOOST_PP_REPEAT in this case?
Just realized that commas do not affect anything here, so the straghtforward BOOST_PP_REPEAT invocation does the job: #define EXPR(z, x, text) BOOST_PP_COMMA_IF(x) param1, param2, arr1[x], arr2[x] #define REPEAT_PARAMS(x) BOOST_PP_REPEAT(x, EXPR, _) func(count, REPEAT_PARAMS(5)); Sorry for the noise.
participants (2)
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Igor R -
niXman