[Haskell-cafe] Re: (Chaos) [An interesting toy]

[Duncan Coutts]

On Mon, 2007-05-07 at 21:50 +0100, David House wrote:
> On 07/05/07, Andrew Coppin <andrewcoppin at btinternet.com> wrote:
> > (Anybody know what the difference between GHC.Prim.Double#
> > and GHC.Float.Double is?)
> 
> It's the difference between unboxed and boxed types. A boxed type's
> representation is in fact a pointer to the unboxed type (I think), so
> that a Double would be internally represented to a pointer to a
> Double#. As a consequence, a Double can be _|_, because this can be
> represented by a null pointer.

Rather it can be represented by a code thunk that when called raises an
exception or does not terminate. (It's never a 0-pointer)

Duncan