Book Image

Learning Functional Programming in Go

By : Lex Sheehan
Book Image

Learning Functional Programming in Go

By: Lex Sheehan

Overview of this book

Lex Sheehan begins slowly, using easy-to-understand illustrations and working Go code to teach core functional programming (FP) principles such as referential transparency, laziness, recursion, currying, and chaining continuations. This book is a tutorial for programmers looking to learn FP and apply it to write better code. Lex guides readers from basic techniques to advanced topics in a logical, concise, and clear progression. The book is divided into four modules. The first module explains the functional style of programming: pure functional programming, manipulating collections, and using higher-order functions. In the second module, you will learn design patterns that you can use to build FP-style applications. In the next module, you will learn FP techniques that you can use to improve your API signatures, increase performance, and build better cloud-native applications. The last module covers Category Theory, Functors, Monoids, Monads, Type classes and Generics. By the end of the book, you will be adept at building applications the FP way.
Table of Contents (21 chapters)
Title Page
Credits
About the Author
Acknowledgments
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface
Index

Introducing the pipeline pattern


The pipeline software design pattern is used in cases where data flows through a sequence of stages where the output of the previous stage is the input of the next. Each step can be thought of as a filter operation that transforms the data in some way. Buffering is frequently implemented between filters to prevent deadlock or data loss when one filter runs faster than another filter connected to it. Connecting the filters into a pipeline is analogous to function composition.

The following diagram depicts the flow of data from a data source, for example, a file. The data is transformed as it passes from one filter to the next, until the result is finally displayed on standard out in the console:

Grep sort example

The /etc/groupfile is the data source. Grep is the first filter whose input is all the lines from the /etc/group file. The grep command removes all lines that do not begin with "com", and then sends its output to the Unix pipe, which sends that data...