package orsetto

The abstract type of monad with a parameter for its return type.

Define return a to apply a to the bound function.

Define bind m f to apply the value returned by m to the function f to obtain the result monad.

Define mapping to select the `map` operator to be either the default fun a -> return (f a) or as some other special map function.

Define product to select the `product` operator to be either fun a b -> bind a (fun r1 -> bind b (fun r2 -> return (r1, r2))) or some other special function.