ghc -fglasgow-exts -fallow-undecidable-instances allows
constructs which amount to lambda abstraction over types.
I've written a small untyped lambda calculus interpreter
in the Haskell class/instance sublanguage, just to prove
this point. (The terms are Haskell *types*.)
Fun with Haskell types. Check out the source code.
Posted to functional by Ehud Lamm on 3/23/02; 3:32:59 AM