Mastering Functional Programming

Execution semantics abstraction

The capabilities type class is on equal ground with the Monad type class. The Monad type class defines how you would compose the computation sequentially. There is a saying that Monad is the semicolon of functional programming. Why would people say that? What is the role of a semicolon in object-oriented programming? In ordinary imperative programming, a semicolon is a symbol that separates one statement from another. The meaning of a semicolon is that one statement should be executed after another statement. In a sense, you can treat a semicolon as an operator of the sequential combination of two computation.

The flatMap function does exactly that for the functional programming world. flatMap defines how ...