Re: [Boost-users] Preprocessor Question

--- Peter Bartlett wrote:

Quoting Ed Keith :

...

--- Peter Bartlett wrote:

...

Quoting Ed Keith :

...

[...]

BOOST_PP_IF(abc == abc, foo, bar)

I get an error.

Is it possible to do something like this? If

so,

...

...

what

...

am I doing wrong?

I think you have to use BOOST_PP_IF( BOOST_PP_EQUAL(abc,abc) , foo, bar ) here.

I tried that, but apparently BOOST_PP_EQUAL only takes int values.

Thank for the suggestion though,

-EdK

Ok. BOOST_PP_IF has a similar restriction, so you probably can't do what you want with it. Be sure though that even the '#if' version is doing what you want - for example the following program prints 1 on my compiler (VC9):

#if foo == bar int baz() { return 1; } #else int baz() { return 0; } #endif

#include <iostream> int main() { std::cout << "\n" << baz() << "\n"; }

Your right it's not doing what I want. Let me ask a hight level question. What I am trying to do is the following: I have two sequences. Both represent sets, one is a subset of the other. What I want to do is for each element in the superset, generate one value if it is in the subset, and another value if it is not in the subset. The problem is that the elements are not numeric (they are just tokens), so I can not seem to compare them to determine if they are the same. Any sugestions? Thank you, -EdK Ed Keith e_d_k@yahoo.com Blog: edkeith.blogspot.com ____________________________________________________________________________________ Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now. http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ