We recently decided that we needed a new concept, DerivedFrom, to express the requirement for an inheritance relationship between two types. This concept has the following definition:
concept DerivedFrom<typename Derived, typename Base> { /*unspecified*/ }
DerivedFrom is a compiler-support concept, like SameType. We expect that most of its uses will be to intermingle the object-oriented and generic programming facilities of C++0x, e.g.,
template<typename T>
requires DerivedFrom<T, Shape>
void draw(T& shape) {
// Can use Shape's member functions via "shape" object.
}
DerivedFrom is now supported (albeit “lightly tested”) in the development version of ConceptGCC.
