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

Sequence of an indefinite length as a design pattern


The conventional engineering vision of data transformations is that they occur over finite collections materialized in the memory, hence allowing these collections to be enumerated with Seq.length, yielding a number of elements. However, the F# sequences (as well as .NET IEnumerable<T> per se) grant the following generalization: in some cases, a more math-centric vision might be useful, which suggests looking at sequences as countable but not necessarily finite.

A meticulous reader may immediately object that the countable entity, when applied to practical computing, is necessarily finite because eventually, it is limited by underlying physical hardware, which comes out in boundary values, for example:

System.Int32.MaxValue = 2147483647 
System.Int64.MaxValue = 9223372036854775807L 

However, I would oppose this objection by saying that this mere consideration does not in any way limit the length of the F# sequences that might be produced...