sean.seefried:
I still don't see clearly. So you've implemented the type inference algorithm from Jones' paper, good. But is there any significance or gain, apart from it being a nice and interesting exercise?
No. Nor did I state that there was. There's a reason I posted this to Haskell-cafe and not Haskell. I just thought the code might be useful for other people who were similarly trying to understand how constructor classes are implemented. The only other code I found (that wasn't inside a compiler) was that associated with the "Typing Haskell in Haskell" paper. The nice thing about the algorithm in "A system of constructor classes: ..." is that it is small and to-the- point.
Seems like useful code to me. The more the merrier :) -- Don