I think you're munging your terminology. Side-effectful computations in haskell are done inside the IO monad. A monad is not in general a thing for side-effectf

I think you're munging your terminology. Side-effectful computations in haskell are done inside the IO monad. A monad is not in general a thing for side-effectful computation. They are made unnecessary for side-effectful computation in o'caml because of the inherent support for mutability. Indeed side-effectful computation can be represented as a monad, and therefore the ; in ocaml might be interpreted as a bind. Something just needs to satisfy the monad laws in order to be a monad. However, in Haskell the IO monad is explicitly defined. This is very important. The do syntax is sugar over monadic binding them together. In ocaml, sequential computation is simply scheduled sequentially. In haskell, something of type IO () is a VALUE which corresponds to an ACTION which can be RUN. The function which returns the IO action is still pure. It is the outside world which consumes the IO action and performs it. In o'caml, functions are merely impure as in other languages. The function that prints 3 and returns 8 in ocaml has type "int". The function that prints 3 and returns 8 in haskell has type "IO Int"...