[Haskell-cafe] Re: ANN: Data.Stream 0.4

Bas van Dijk wrote:

1) What's the difference between your: "tail ~(Cons _ xs) = xs" and the more simple: "tailStrict (Cons _ xs) = xs" ?

I know they're desugared to: "tail ys = let Cons _ xs = ys in xs" and: "tailStrict ys = case ys of Cons _ xs -> xs" respectively.

But aren't they operationally the same:

"tail undefined = undefined" and: "tailStrict undefined = undefined"

I concur, a strict tail is enough. Writing foo xs = bar (tail xs) has the same effect as foo xs = bar (tailStrict xs) since the evaluation of xs is deferred in both cases. Regards, apfelmus -- http://apfelmus.nfshost.com