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

On Mon, 2007-05-07 at 21:50 +0100, David House wrote:

On 07/05/07, Andrew Coppin 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