[Haskell-cafe] Functional progr., images, laziness and all therest

[Ross Paterson]

On Thu, Jun 22, 2006 at 05:44:58PM +0100, I wrote:
> It works because Haskell 'data' definitions yield both an initial fixed
> point (with respect to strict functions) and a terminal fixed point (with
> respect to arbitrary functions), and moreover these are usually the same.
> The former is inductive, the latter co-inductive.  They differ only when
> the definition is strict in the recursive type, as in
> 
> 	data Nat = Zero | Succ !Nat

On second thoughts, I think the fixed points coincide in these cases
too.