[jhc] some FFI questions

First of all, I'm wondering what the intended uses of the lookupCType and lookupCType' functions are. It seems like lookupCType tells you the type that should be used in marshalling a type, and lookupCType tells you the primitive type that is used in the representation of a type as well as how to extract the value from it. I'm not sure how to go from there to actually converting to/from the correct primitive type to use in interfacing with C code... Another question is: what sort of E type should an imperative foreign export use? Consider: foreign export hello :: Int -> IO () hello n = putStrLn ("Hello, "++show n) foreign export foo :: IO Int foo :: Num a => IO a foo = return 1 Should they just use IO? I guess that's what main does...