On 09/17/2012 03:33 AM, Jonathan M Davis wrote:
On Monday, September 17, 2012 03:27:10 Timon Gehr wrote:
On 09/17/2012 02:23 AM, Jonathan M Davis wrote:
... That might make sense for an int, since
it can't be null, but pointers and references _can_ be and are in every
type system that I've ever used.
...
You have claimed multiple times to have used Haskell.
I have, but I've never used pointers in haskell, so if they're non-nullable, I
wouldn't know about it. I believe that everything in Haskell is an immutable
value type as far as what I've dealt with goes.
- Jonathan M Davis
In effect, everything is a non-null reference to mutable, but as
mutation is constrained rather specifically, it is possible to reason
about the behaviour of Haskell programs on a higher level of
abstraction.
> let fib n = if n<2 then n else fib (n-1) + fib (n-2)
> let x = fib 30
> let y = x
> let z = x
> y
(delay)
832040
> z
(no delay)
832040
