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

Type augmentation


The opposite of generalization is specialization, and it is associated with type augmentation in F#. It is worth noting that the official F# 4.0 Language Specification (http://fsharp.org/specs/language-spec/4.0/FSharpSpec-4.0-latest.pdf) does not introduce this terminology using type extension instead. Nevertheless, the type augmentation expression is de-facto ubiquitous and used interchangeably with type extension. Personally, I believe that augmentation is free of the undesired connotation that extension carries as something that's added to an existing matter. Augmentation is a better synonym for the specialization of an existing matter by adding, customizing, or even removing features. So we will stick to it here.

The following figure shows two flavors of type augmentation available in F#. Both use the same syntax but represent different use cases. Intrinsic augmentation customizes your own code, while optional augmentation may customize types outside of your code:

F...