| 1) Coerce a a can be defined as coerce=id for all a. However, this
|may of course lead to overlap in the type structure, so we must
|write a separate instance definition for Coerce Int Int, Coerce
|Double Double, etc. if we want types to be decidable. I'd love for
|some clever
Simon PJ replies:
> Ingenious, but unnecessarily complicated. You don't need existential
> types at all.
> (See the code below, which is considerably simpler and, I fancy, a bit
> more efficient.) Also, I'm not sure why you make 'Type' (which is
> pretty much the Typable class in the Dynamic libra
| The following is a more flexible alternative to overloading. We
| essentially define a function on types and invoke it, seemingly at run
| time. No Dynamics or unsafe computations are employed. We only need
| existential types, multi-parameter classes and functional
| dependencies. The code also
