Re: [Haskell-cafe] A guess on stack-overflows - thunks build-up and tail recursion

On Fri, Mar 20, 2009 at 11:59 AM, GüŸnther Schmidt wrote:

I apparently can have a huge thunk build up eventhough I use a supposedly accumulative, tail-recursive algorithm.

This is correct. If you don't strictly evaluate your accumulator before you tail recursive, a thunk will build up. See the tail recursive foldl for example in: http://haskell.org/haskellwiki/Foldr_Foldl_Foldl%27 This is why you probably always need the strict foldl' instead of foldl. regards, Bas