Hi all, For some time now I have been wondering if it is possible to implement the ST monad (with polymorphic newVar, writeVar, and readVar) in "pure" Haskell. One might be allowed to use existential/universal quantification in types, but no dynamic types or explicit type casts. I do not care about space or time efficiency, so a lookup table implemented as a list would work. I recently got some new insights about how this might be possible. Has anyone done this before? Or is there a proof that it is not possible? Regards, Koen. -- Koen Claessen, [EMAIL PROTECTED], http://www.cs.chalmers.se/~koen, Chalmers University of Technology.
