Applicative Functor
An applicative functor is a functional programming concept that extends functors by allowing functions to be applied to values within a context, such as lists, options, or monads, enabling sequential computations without explicit unwrapping. It provides a way to combine multiple effectful computations in a pure, declarative manner, often used for validation, parsing, and handling side effects. In practice, it sits between functors and monads in the functional hierarchy, offering more power than functors but less complexity than monads.
Developers should learn applicative functors when working in functional languages like Haskell, Scala, or F# to handle computations with effects (e.g., errors, optional values, or concurrency) in a composable way, especially for tasks like form validation where multiple independent checks need to be combined. It's useful in scenarios requiring parallel or independent operations, as it avoids the sequential constraints of monads, making code more modular and testable in functional paradigms.