When implementing a tool for a heterogeneous language,
I want to write a coerce function that allows me
to coerce among different existential types:
-- use -fglasgow-exts -package lang
import Dynamic
class (Typeable id, Typeable as) =>
Syntax id as | id -> as
where parse :: id -> as
I have found what is either a problem in ghc/ghci or a problem in my
understanding...
either way if someone could point out whats wrong I would be very grateful.
I am experimenting with monad-transformers, and am tying to define a class
to allow a
run function to be overloaded. The program layers
