2023 01 06 FP Patterns

A software pattern is a reusable solution to a commonly occurring problem within a given context in software design. Software patterns mean that we do not have to start from scratch every time we write code. A software pattern is a template for solving a type of problem.

Functional programs use code constructs that are immutable, obey referential transparency, use higher order functions, and make liberal use of functional patterns.

category theory based
Functor, Monoid, and Monad patterns

Patterns

Option pattern

The Option class comes in two flavors: Some and None.

The Option pattern is perfect for problems that involve a null value. The idea is to have an object represent the case that nulls are used for but to do it with a type. The Option trait addresses this problem exactly. Option comes in two flavors. Some(), a wrapper around a value, such as Some(user), and None, which represents the case where there is no answer, the case often expressed by null. But None has a type and so the compiler can check that the code is correct.

Sources

Learning Functional programming by Jack Widman in aug. 2022