I forgot to send this reponse to haskell-cafe earlier... Hello,
You mean for the IO monad, right?
Sorry. I meant divergence is unavoidable for any strict Monad, such as IO. However, sequence will always compute over the entire list; if the resulting computation itself is lazy then the result can be inspected lazily.
take 10 $ execWriter $ sequence $ repeat $ tell ([3]::[Int])
This is a good example. Note that the computation of sequence itself is infinite. snd $ runWriter $ sequence (repeat $ tell [3]) >>= return . take 10 will result in an infinite list, but fst $ runWriter $ sequence (repeat $ tell [3]) >>= return . take 10 will return a 10 element list. -Jeff --- This e-mail may contain confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error) please notify the sender immediately and destroy this e-mail. Any unauthorized copying, disclosure or distribution of the material in this e-mail is strictly forbidden.