Re: [Haskell-cafe] I miss OO

It would be fantastic to have a little practical real-world challenge (like building a simple music system, or a simple multi-channel sound mixer), and work this out in an imperative language, an object-oriented language, a functional language, and maybe other languages too, like logic languages or constraint languages (does the latter exist?)

There are some constraint languages. But I do not know whether they are general purpose (or even Turing complete). I have used ZIMPL, which is a language for specifying mixed integer linear optimization problems (which is somewhat related to constraint programming). Though it would not be useful for a music system.