Learning Functional Programming in Go

Monadic functions

Monads are implemented as a type class with two methods, return and bind (>>=):

class Monad m where return :: a -> m a  (>>=) :: m a -> (a -> m b) -> m b

Note that m refers to a type constructor, such as Either or Maybe, that implements the Monad type class.

We'll include a few more monadic functions from the Standard Library in the following table:

Function	Description
fail	The fail function supports a monad's implementation of failure. We get the fail function from the Monad type class, and it enables a failed pattern matching to result in a failure in the context of the current monad instead of a program crash. For example, the fail function is called when pattern matching fails in a do expression.  fail :: ...