Koen Claessen (me) wrote about transforming away existentials:
| > I have applied this method several times when I thought I needed
| > existential types, but I didn't need them at all. I think this might be
| > the case more often.
Christian Sievers answered:
| I believe it is always possible, but it soon gets unmanagable.
How about polymorphic member functions in the classes? You will then need
polymorphism in data constructors, which is also an extension of the type
system.
Though, if you only allow existential types that do not refer to member
functions in type classes, then I indeed believe it is always possible.
Regards,
Koen.
--
Koen Claessen,
[EMAIL PROTECTED],
http://www.cs.chalmers.se/~koen,
Chalmers University of Technology.
