Throughout this message you imply, if not outright state, that Dynamics requires unsafeCoerce/unsafePerformIO. This is simply not the case. GHC implements Dynamics with unsafeCoerce, or did last time I checked, but it can easily be implemented using only existentials. (I presume that this decision was made either for efficiency, simplicity, and/or simply that another (readily useable) technique was not known when the library was made.)
Anyways, as I have often mentioned, "A Lightweight Implementation of Generics and Dynamics" has an unsafePerformIO/Coerce free implementation of Dynamics as well as Generics as the title suggests. _______________________________________________ Haskell mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell