On Thu, Dec 15, 2011 at 8:26 AM, Lorenzo Caminiti <lorcaminiti@gmail.com>wrote: [...]
I'm asking because Boost.Contract will support both type predicates and concepts so I need to tell the users why they can use both, when to use concepts, and when to use type predicates. Actually, Boost.Parameter also supports both because it can be used together with Boost.Concept so IMO it'd be nice to add the same explanation to Boost.Parameter as well.
I don't think Boost.Contract nor Boost.Parameter is special in this regard. The guideline I follow is: use type predicates only to differentiate between overloads via SFINAE; otherwise, use concept assertions, as they typically provide more informative error messages and don't complicate the function signature. - Jeff