--- Wolfgang Jeltsch <[EMAIL PROTECTED]> wrote: > > > I think Phil Wadler said it best when he said that a monad is a > > *computation*.
To be honest, I'm still struggling with the monad concept myself. Oh sure, I can read the definition and it makes sense. But I'm still missing that "aha!" moment when it all comes together. > > No, a value of type IO <something> is a computation. The type IO > plus (>>=) > plus return is a monad. So is [] plus concatMap plus \x -> [x]. This may be totally off-base, but when I read this, it occured to me that all I/O is basically a computation made to appear as if it is something your program "does". You (or, rather the processor) don't execute instructions to write "Hello" in same way as, say, adding 2 and 2. Rather, you add writing this string to a "to do" list and wait for a driver to respond to an interrupt, pick up the request(s), and carry it (them) out when control passes back the kernel. > === Gregory Woodhouse <[EMAIL PROTECTED]> "Interaction is the mind-body problem of computing." --Philip L. Wadler _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
