Hi
How do you plan to implement unboxed types? AFAIK, implementing unboxed types requires a typed intermediate language. Maybe you could get away with boxing all the unboxed types, but then Int would have an extra level of boxing.
Indeed, we intend to box everything. Plus there were compilers which did unboxing before having unboxed types - as the paper said, it wasn't as neat, but it was possible. I also have a design for a C backend where the Int can be packed into the pointer, which removes the boxes from all evaluated Ints.
And the other big problem with implementing GHC core is all the primitives...
The Yhc primitives aren't particularly nice, but we have a design in which they could be made much nicer, and also allow implementation of the GHC core primitives easily. This will probably be the larger chunk of work. Thanks Neil