Ruby is not only for Objective Oriented Programming style, but also for Functional Programming style. I talk how ruby expresses important essences of Functional Programming. For example, Functor, Applicative, Monad.

And Monadic syntax suger is very important to take advantage of Monad. I also talk about Implementation of Monadic syntax suger that is inspired by Scala language. I will show popular monad implementations like belows. - Maybe - Either - State - Future (like async syntax in JavaScript) - Parser Combinator