| Thanks all, Now that I have a (very) rudimentary understanding of Haskell, I figured I'd back up and have a closer (conceptual) look at type definitions to see what they have in common, and just happen to pick Maybe and List. I also noticed Maybe has a list of "Instances" Monad Maybe Functor Maybe Typeable1 Maybe MonadFix Maybe MonadPlus Maybe etc. while List has none, at least I don't see any in Data.List. Same reason? From "Learn You A Haskell:" "If a type is a part of a typeclass, that means it supports and implements the behavior the typeclass describes." I'm way out on a limb here, but isn't Monad a typeclass? and if, as we say above, that Maybe is an instance of Monad, wouldn't there have to be instance Monad Maybe where return = ... -- return for Maybe >>= = ... -- bind for Maybe etc. somewhere? Where? It's not in Data.Maybe. Is there some kind of scheme for defining this stuff, i.e., this goes here, that goes there? Michael --- On Fri, 7/30/10, Edward Z. Yang <ezyang@MIT.EDU> wrote:
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