Request: withArrayLength

Hello, The FFI currently provides.. withArray :: Storable a => [a] -> (Ptr a -> IO b) -> IO b I think.. withArrayLength :: Storable a => [a] -> (Ptr a -> Int -> IO b) -> IO b would be useful because you often need the length in a foreign function and I guess withArray must pre-calculate the length before allocating storage in any case (or at least must know the length by the time marshalling is finished). It seems a pity to waste time calculating it twice. Actually, looking at the ffi again I see there is something similar for CStrings already, but not for arrays in general. Is this an oversight or a deliberate decision? Regards -- Adrian Hey