Hello Gabriel, Tuesday, August 15, 2006, 10:36:28 PM, you wrote:
| Moreover, Haskell type classes supports inheritance. Run-time | polymorphism together with inheritance are often seen as OOP | distinctive points, so during long time i considered type classes as a | form of OOP implementation. but that's wrong! Haskell type classes | build on different basis, so they are like C++ templates with added | inheritance and run-time polymorphism! And this means that usage of | type classes is different from using classes, with its own strong and | weak points.
Roughly Haskell type classes correspond to parameterized abstract classes in C++ (i.e. class templates with virtual functions representing the operations). Instance declarations correspond to derivation and implementations of those parameterized classes.
i can't agree. the differences between TC inheritance/polymorphism and C++ classes are substantial. i listed them in next part of tutorial which you should see alongside this message. you can also see paper at http://homepages.cwi.nl/~ralf/gpce06/ which is all about consequences of differences between classes and type classes for software development -- Best regards, Bulat mailto:Bulat.Ziganshin@gmail.com