Finally, monads are a fascinating and useful concept that pervades many types in the Scala standard library. Option, Future, Either, and more or less all the collection types such as List, Tree, and Map, to name a few, are monads.

What is a Functor and monad?

A functor is a data type that implements the Functor typeclass. An applicative is a data type that implements the Applicative typeclass. A monad is a data type that implements the Monad typeclass. A Maybe implements all three, so it is a functor, an applicative, and a monad.

Is Monoid a monad?

@AlexanderBelopolsky, technically, a monad is a monoid in the monoidal category of endofunctors equipped with functor composition as its product. In contrast, classical “algebraic monoids” are monoids in the monoidal category of sets equipped with the cartesian product as its product.