Modelling Typeclasses in C++

Question

Is it possible to implement Haskell typeclasses in C++? If yes, then how?

Answer 1

There's a few papers on this, which might be useful as background reading:

• C++ templates/traits versus Haskell type classes, Sunil Kothari , Martin Sulzmann
• A Comparative Study of Language Support for Generic Programming, Ronald Garcia , Jaakko Järvi , Andrew Lumsdaine , Jeremy Siek , Jeremiah Willcock

Answer 2

The similar mechanism in C++ is called "concepts". The idea is to define a typeclass by defining the requirements of any type belonging to that class. C++ iterators make extensive use of concepts, and C++0x had intended to support direct syntax for them (rather than the indirect template tricks to perform concept checks C++ currently employs), but it appears this support has been dropped from the standard.