The expression sequence [a,b,c,...] is roughly equivalent to do r_a <- a r_b <- b r_c <- c ... return [r_a,r_b,r_c,...] The expression sequence_ [a,b,c,...] is roughly equivalent to do a b c ... return () Does that help? Cheers, Greg On 10/29/10 10:07 PM, Mark Spezzano wrote:
Hi,
Can somebody please explain exactly how the monad functions "sequence" and "sequence_" are meant to work?
I have almost every Haskell textbook, but there's surprisingly little information in them about the two functions.
From what I can gather, "sequence" and "sequence_" behave differently depending on the types of the Monads that they are processing. Is this correct? Some concrete examples would be really helpful.
Even references to some research papers that explain the rationale behind these (and all the other..?) monad functions would be great.
Thanks in advance,
Mark Spezzano _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe