frederic.bron@alcan.com wrote:
Dear boost implementers, TypeTraits is very useful, thanks you. However, recently, I needed something to know if a type is comparable (with operator<) and that was not in the library. Fortunately, somebody forwarded me an earlier post on the users list where I could find what I wanted. The implementation was inspired from boost/detail/is_incrementable.hpp I have written is_less_comparable, is_less_equal_comparable, is_greater_comparable... inspired from the same source and I wonder if it could be possible to add it to the library as I think it could be helpful for others. I give the source code below (if it is useful) but I am not able to make it fully general as it is in boost/type_traits. In particular, I do not understand all the macros that are used.
It would really be nice to have type_traits for all the possible user-defined operators. As part of that it seems that boost/detail/is_incrementable.hpp could be lifted from the boost::detail namespace and put into those new type_traits. I know you mentioned subsequently in another post that you are working on more of the operators but I do not know if you had decided to provide type_traits for all of the user-defined operators. If you had not decided to do all of them, I would like to encourage you to do so if you feel that the work to do them is not overwhelming. I will be glad to help test them out from within my own work since I am developing a template library in which I could use all of them.