On Sat, 2011-01-15 at 22:43 -0500, Jan-Willem Maessen wrote:
Which of course says nothing about which form is easier to *write*, but I'm inclined to believe that it's easiest to read and write the form whose use you understand best (ie brevity is not the sole criterion here by any means; understandability has to be paramount). My bias is to assume my reader is, like me, a programmer first and a mathematician second. For example, I find it relatively easy to understand >>= in the continuation monad, but have to spend a long time puzzling my way through join. For simple stuff like [] and Maybe, of course, the code complexity argument is moot, and join is pretty natural unless you spend your time re-formulating list comprehensions for fun.
-Jan-Willem Maessen
I agree that there are advantages of both ways and they are perfectly compatible with each other. While I don't know about GHC internals I'd assume that class v-tables (term borrowed from C++ I'm not sure about Haskell terminology) is per-class and not copied for each function invocation. Therefore if we can include both ways which can be interleaved (Monad written by 'join' person can be used by 'bind' person and vice-versa) why don't do that? I don't think there is anyone who propose to remove (>>=) from Monad class. As of simplification - I find join simpler as it allows to pattern match in some cases and have one 'complicated' parameter less. You may find bind simpler as it is closer to imperative style. However I often use (>>=)/do notation. Regards PS. I don't think I constitute a mathematician - I don't know much about theory of categories except pieces I learn along Haskell.