Hello all, How can I use Boost.ConceptCheck to implement "not" and "or" concept constraints as they are defined in N2081? (If this is obvious from the documentation, please just point me to the link.) For example, how can I program the following code from N2081 using Boost.ConceptCheck: // "not" `!` concept constraint for some concept C (not C++ code). template<Regular T> where !C<T> void f(T x) { ... } // "or" `||` concept constraint (not C++ code). template<Regular T> where Integral<T> || Floating<T> T cos(T x) { ... } If I understand it right, I can program the "and" concept constraints in Boost.ConceptCheck just by specifying multiple concepts as in: // "and" `&&` concept constraint. template<typename T> BOOST_CONCEPT_REQUIRES( ((boost::Integral<T>)) ((boost:: Arithmetic<T>)), T) f(T x) { ... } But how do I use BOOST_CONCEPT_REQUIRES(), etc to program "not" and "or" concept constraints? Thank you very much. -- Lorenzo