[Haskell-cafe] Could FFI support pass-by-value of structs?

It's not usual, but it is allowed to have values of structs passed between functions directly instead of using pointers: /*****/ struct ex { int x; int y; int z; }; ex example_functions (ex p) { (...) } /*****/ Would it be possible to allow that in Haskell FFI by, say, allowing any instance of Storable to be used in a 'foreign' declaration? Like: -- data Ex = (...) instance Storable Ex where sizeOf _ = ... alignment = sizeOf (...) foreign import ccall "example_functions" exampleFunction :: Ex -> IO Ex -- Thanks, Maurício