Parameter Make2.X

Multi parameter monad. The second parameter gets unified across all the computation. This is used to encode monads working on a multi parameter data structure like (('a,'b) result).

type ('a, 'e) t
val bind : ('a, 'e) t -> ('a -> ('b, 'e) t) -> ('b, 'e) t
val return : 'a -> ('a, _) t

The following identities ought to hold (for some value of =):

Note: >>= is the infix notation for bind)