Barney Hilken wrote:
I totally disagree. The great strength of Haskell is that, whenever important design decisions have been made, the primary consideration has not been practicality, but generality and mathematical foundation. When the Haskell committee first started work, many people said lazy evaluation was an academic curiosity: mathematically right, but far too inefficient for real programs. When Haskell adopted type classes, people said they were far too heavy a machinery to solve the relatively simple problems of equality, show and numbers. In each case the more general, abstract approach has shown enormous advantages in the long term. I'm sure the same will be true of associated types, which are a lot more complex than functional dependencies, but also more general, and more mathematical.
While I agree with your general argument, I wonder if you realize that functional dependencies have a strong, general, and elegant mathematical foundation that long predates their use in Haskell? If you want even a brief glimpse, there's s short article at http://en.wikipedia.org/wiki/Functional_dependencies that might give you some ideas. The mathematics of functional dependencies plays an important role in the theory of relational databases. I don't know what you consider as the mathematical foundations for associated types, nor do I know why you consider that to be either more general or more "mathematical" (whatever that means) but I hope you'll enjoy the material on functional dependencies. All the best, Mark _______________________________________________ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
