On Wed, 23 Jul 2008 22:11:10 -0300, "Rafael Gustavo da Cunha Pereira
Pinto"
[...]
I have a few problems:
a) the DNA is 8MB long. How can I ensure the stack will hold a recursive call?
Forgive me if I'm wrong, but on a hunch, but this sounds like an issue that could possibly be solved using tail recursion. For example, according to "Recursion in a monad - HaskellWiki" (http://haskell.org/haskellwiki/Recursion_in_a_monad), here is a monadic do-block reads 'n' lines from stdin, using a linear recursive process: main = f 3 f 0 = return [] f n = do v <- getLine vs <- f (n-1) return $! v : vs This runs as follows: $ runhaskell A.hs 1 2 3 ["1","2","3"] Rewriting the code to make it use a linear iterative process (using tail recursion) results in the following code: f 0 acc = return (reverse acc) f n acc = do v <- getLine f (n-1) (v : acc) Here, "acc" stands for an accumulator, which is a register (here, a variable simulating a register) to store temporary values. This rewrite enables the process to use constant stack space. Using this idea, it may be possible to rewrite your recursive function process::ByteString -> a to use constant stack space. -- Benjamin L. Russell