On Tue, Jul 14, 2009 at 6:02 PM, Thomas Hartman<tphya...@gmail.com> wrote: > myiterate f x = > let nxt = f x > in nxt `seq` x : myiterate f nxt
iterate' f x = x `seq` x : iterate' f (f x) seems better; it doesn't evaluate list elements you don't visit. > let test = 1 : 2 : 3 : undefined in last $ take 4 $ myiterate (test !!) 0 *** Exception: Prelude.undefined > let test = 1 : 2 : 3 : undefined in last $ take 4 $ iterate' (test!!) 0 3 -- ryan _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
