New subject: [Preprocessor] how to use REPEAT_FROM_TO for 2 arguments

6 Jan 2010

      Hi,

I am trying to use the preprocessor library to simplify the code I have.

The problem:
I have many lines of the following assignments:

mybfclass x_0_mybf;
mybfclass x_1_mybf;
...
mybfclass1 x_0_mybf1;
mybfclass1 x_1_mybf1;
...
mybfclass2 x_0_mybf2;
mybfclass2 x_1_mybf2;

then I defined several vectors:

vector x_mybf;
vector x_mybf1;
vector x_mybf2;
*
use the boost preprocessor library, I write the following code:

#define* DECLX_mybf(z, n, text) BOOST_PP_CAT(text, BOOST_PP_CAT(_,
mybf)).push_back(&BOOST_PP_CAT(text, BOOST_PP_CAT(BOOST_PP_CAT(_, n),
BOOST_PP_CAT(_, mybf))));
*#define* DECLX_mybf1(z, n, text) BOOST_PP_CAT(text, BOOST_PP_CAT(_,
mybf)).push_back(&BOOST_PP_CAT(text, BOOST_PP_CAT(BOOST_PP_CAT(_, n),
BOOST_PP_CAT(_, mybf))));
*#define* DECLX_mybf2(z, n, text) BOOST_PP_CAT(text, BOOST_PP_CAT(_,
mybf)).push_back(&BOOST_PP_CAT(text, BOOST_PP_CAT(BOOST_PP_CAT(_, n),
BOOST_PP_CAT(_, mybf))));

BOOST_PP_REPEAT_FROM_TO(0, 2, DECLX_mybf, x);
*// generated: x_mybf.push_back(&x_0_mybf); x_mybf.push_back(&x_1_mybf);
* BOOST_PP_REPEAT_FROM_TO(0, 2, DECLX_mybf1, x);
*// generated: x_mybf1.push_back(&x_0_mybf1); x_mybf1.push_back(&x_1_mybf);
* BOOST_PP_REPEAT_FROM_TO(0, 2, DECLX_mybf2, x);
*// generated: x_mybf2.push_back(&x_0_mybf2); x_mybf2.push_back(&x_1_mybf);
*
but I think it is too much coding here, since I have to write a macro for
each mybf occurrence, DECLX_mybf

I have difficulty to use the BOOST_PP_REPEAT_FROM_TO for two argument, since
the macro(z, x, data) can only accept one argument data, however, I need to
pass two arguments x and mybf to the macro,
in order to generate a mybfclass1 x_0_mybf.

does anyone know how to apply macro to generate the above structure?

thanks.

/Kenny

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[Preprocessor] how to use REPEAT_FROM_TO for 2 arguments

Kai Liu

Steven Watanabe

Kai Liu

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