# Functional Programming | | In computer science, **Functional Programming** is a programming paradigm where programs are constructed by applying and composing functions. It is a declarative programming paradigm in which function definitions are trees of expressions that map values to other values, rather than a sequence of imperative statements which update the running state of the program. | |-|-| | | wikipedia:: [Functional programming](https://en.wikipedia.org/wiki/Functional_programming) | - "In general, we recommend that you write pure functions whenever it is reasonable to do so and resort to modifiers only if there is a compelling advantage. This approach might be called a functional programming style." ## Lambda Calculus ## No side effects - [[Side effect (computer science)]]