From: Jesse Perla >>I think the best solution for dynamic constraints union (or intersection) is to >>use boost::signal, and this is how I would implement this. Again, this is a >>possible addition to the library in the future if it proves generally needed. >Yes, the signals approach would solve multiple constraint bounds-checking through a predicate. But it doesn't solve my main use case: Querying the sub-type information associated with a type for numeric algorithms, which may not be connected intervals. Oh, I see now. So instead of using boost::signal (which performs type erasure) it'd be better to define a predicate containing a std::vector<within_bounds<...>
. This way you could, by accessing this predicate, iterate over the intervals and query the bounds.
>>On numeric_limits: >>Then you may specialise those functions for constrained -- I think it's a better >>solution than providing numeric_limits for constrained in the library. > I hear what you are saying. Yu can't write your own numeric_limits classes/functions... they are very platform specific and are part of the standard. Though there may be ways to subclass from your super-type. The standard allows to specialise numeric_limits. So I suspect you could write (somebody please correct me if I'm wrong): #include <limits> namespace std { template<typename V, typename C, typename E> class numeric_limits< constrained<V, C, E> > : public numeric_limits<V> { }; } I don't know if it would be a good idea to include this in the library, but you could definitely use this in your programs. > I will get back in contact early January to see how I can help after the review has died down. Thanks! :-) Best regards, Robert