Add BOOST_PP_ENUM_TRINARY_PARAMS()

[Vadim Zeitlin <vz-boost@…>]

I'd like to have a generalization of BOOST_PP_ENUM_BINARY_PARAMS() to 3 parts. This would be useful to generate the parameters of a function like

template <typename F1, typename T1, ...>
int CompareFields(F1 T1::*f1, ..., FN TN::*fN);

which can't (unless I'm missing something) be easily generated currently. And looking at boost/preprocessor/repetition/enum_binary_params.hpp implementing this manually doesn't look very simple so it would be nice if the library could provide it.

I could (try to) make a patch adding this myself if it has any chance of being accepted, please let me know if it would be.

[Steven Watanabe]

You can use BOOST_PP_ENUM which is completely general. If you really want to implement ENUM_TERNARY_PARAMS (including documentation and tests) I suppose it wouldn't hurt to add it, but I don't think it's worth the effort.