Today, we will discuss the concepts of functors, applicatives, and monads in functional programming with examples in Haskell. Functors allow mapping functions over values inside a context without altering the context, like a box that doesn’t change with the value inside. Applicatives extend functors by allowing the application of functions inside contexts to values in the same context. Monads further extend this by providing sequencing and composing actions while maintaining their contexts. Despite some controversy with a negative review from the Haskell Foundation, understanding these abstractions can lead to powerful and concise code in Haskell. Monads, in particular, play a significant role in expanding the capabilities of functional programming.
https://www.thecoder.cafe/p/functors-applicatives-monads