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?
What I woukld write is borrowed from the inner mechanics of Boost::PP. let's say you have two token FOO & BAR. #define IS_SAME_TOKEN_FOO_FOO 1 #define IS_SAME_TOKEN_FOO_BAR 0 #define IS_SAME_TOKEN_BAR_FOO 0 #define IS_SAME_TOKEN_BAR_BAR 0 #define IS_SAME_TOKEN(X,Y) BOOST_PP_CAT(BOOST_PP_CAT(BOOST_PP_CAT(IS_SAME_TOKEN_,X),_),Y) then use IS_SAME_TOKEN in BOOST_PP_IF I knwo it gets cumbersome as the number of tokens increase but I can't see hwo to do it better.