On Fri, Dec 08, 2006 at 03:48:22PM +0000, Simon Peyton-Jones wrote:
| I want to make ByteArray# and MutableByteArray# parameterized over | their element types. ByteArray# would have kind # -> #, and | MutableByteArray#, * -> # -> # . indexByteArray# would have the type | (in pseudo haskell) forall (e::#). ByteArray# e -> Int# -> e.
Probably a bad idea. The point is that you could then write polymorphic functions that would apparently work both on values of type Int# and Double#... but they are of different sizes. Seg-fault city!
Right... which is why you'd need to make sure you never used those functions in a polymorphic way. The code generator should choke if it sees an unlifted type variable. I'm basically looking for a way to avoid enumerating every possible unlifted type in the ByteArray# operations. I'm probably not giving enough details for this to make any sense. I'm actually writing a new ghc backend and I have way more primitive types than the normal dozen or so (actually an infinite number since you can add new ones, I resurrected that "foreign type" code that was leftover from the .NET backend). I'll just try it and see how I make out. -Brian