[Haskell-cafe] Re: instance Eq (a -> b)

Jonas Almström Duregård wrote:

So the facts that (1) f == g (2) f undefined = 6 (3) g undefined = undefined is not a problem?

This is not a problem. f and g represent the same moral function, they are just implemented differently. f is smart enough to know that its argument doesn't matter, so it doesn't need to evaluate it. g waits forever trying to evaluate its function, not knowing it doesn't need it. -- Ashley Yakeley