[Haskell-cafe] Problem trying to get class Bounded to work
bertram.felgenhauer at googlemail.com
Tue May 23 10:56:38 EDT 2006
Jacques Carette wrote:
> Bulat Ziganshin wrote:
> >malloc :: Storable a => IO (Ptr a)
> >malloc = doMalloc undefined
> > where
> > doMalloc :: Storable b => b -> IO (Ptr b)
> > doMalloc dummy = mallocBytes (sizeOf dummy)
> Is there any reason to not code this as
> malloc :: Storable a => IO (Ptr a)
> malloc = mallocBytes $ sizeof undefined
What type would the 'undefined' have in this context?
sizeOf has type Storable a => a -> Int -- that doesn't help.
The purpose of doMalloc is to force the type checker to choose
the right type for that 'undefined'.
More information about the Haskell-Cafe