Simon Marlow
Answer: Hugs has a separate package 'hugs-base' with essential but implementation-dependent things like ForeignPtr in it. (Likewise nhc98/yhc.) The 'base' package just imports and uses it.
As I understand it, Hugs and nhc98 do this by having their own copies of a lot of the library code (up to and including the Prelude?).
Yes. Essentially, we took the view that the Haskell'98 libraries (+ primitives + FFI) can be assumed, and then built the 'base' package on top of that. Whereas GHC took the opposite approach, making 'base' the bottom of the hierarchy and building 'haskell98' on top of that. Hence why lots of GHC-only primitives ended up in 'base', which is not good for a so-called portable package. But I do think that eventually every implementation ought to assume some minimal underlying private libraries, and build 'base' upwards (portably) from there. Regards, Malcolm