Book Image

F# 4.0 Design Patterns

By : Gene Belitski
Book Image

F# 4.0 Design Patterns

By: Gene Belitski

Overview of this book

Following design patterns is a well-known approach to writing better programs that captures and reuses high-level abstractions that are common in many applications. This book will encourage you to develop an idiomatic F# coding skillset by fully embracing the functional-first F# paradigm. It will also help you harness this powerful instrument to write succinct, bug-free, and cross-platform code. F# 4.0 Design Patterns will start off by helping you develop a functional way of thinking. We will show you how beneficial the functional-first paradigm is and how to use it to get the optimum results. The book will help you acquire the practical knowledge of the main functional design patterns, the relationship of which with the traditional Gang of Four set is not straightforward. We will take you through pattern matching, immutable data types, and sequences in F#. We will also uncover advanced functional patterns, look at polymorphic functions, typical data crunching techniques, adjusting code through augmentation, and generalization. Lastly, we will take a look at the advanced techniques to equip you with everything you need to write flawless code.
Table of Contents (20 chapters)
F# 4.0 Design Patterns
Credits
About the Author
Acknowledgements
About the Reviewer
www.PacktPub.com
Preface

Diminishing patterns


Similarly to SOLID principles, many OOP design patterns in the context of idiomatic functional-first F# either diminish (sometimes to the extent of disappearing) or significantly morph. Let's take a quick look at some instances of such transformation. I will be using samples taken from the code base I authored, implementing payment applications for Jet.com. Samples are somewhat simplified to align with the book format.

The Command design pattern

The Command Design Pattern (https://en.wikipedia.org/wiki/Command_pattern) in OOP stands for a behavioral design pattern where all the information required to perform an action at a later time is encapsulated in an object. But wait a minute; doesn't this exactly coincide with what a function is? That's right; almost any idiomatic F# pattern of dealing with a higher-order function to traverse a data structure while applying a lower-order function to each element can be considered an occurrence of the Command pattern. Mapping, folding...