On 9/11/07, PR Stanley <prstanley@ntlworld.com> wrote:

Hi
take 1000 [1..3] still yields [1,2,3]
I thought it was supposed to return an error.
Any ideas?
Thanks, Paul

If for some reason you want a version that does return an error in that situation, you could do something like the following:

take' n _ | (n <= 0) = []
take' n [] | (n > 0) = error "take': list too short"
| otherwise = []
take' n (x:xs) = x : take' (n-1) xs

I'm not sure why you'd want that, though. The standard implementation gracefully handles all inputs, and usually turns out to be what you want. Really, if I were you, instead of making a version take' as above, I would just use the standard take but check for the length of the list in the places where it matters.

-Brent