On 12/11/06, Mark T.B. Carroll
I'm not sure I actually understand them properly yet, but I'm already curious about if anybody's played with them in Haskell, or how useful it would be to do so. Any comments?
Haskell implementations of the transformers in Espinosa's paper are discussed in Mark Jones's 1995 paper Functional Programming with Overloading and Higher-Order Polymorphism, and are available with the mtl package that is (I believe) usable with all the major Haskell compilers and distributed with at least ghc and hugs. (I've never used yhc or jhc, so I don't know what libraries they distribute.) I'm personally fond of framing most non-trivial Haskell problems as defining domain specific languages; as a result, everything over about 200 lines that I've written in the past 3 years has used the mtl in some form or fashion. It's great. /g -- It is myself I have never met, whose face is pasted on the underside of my mind.