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

Predicates


We can use predicates to perform operations on input data. Predicates can be used to implement many of the functions that we apply to collections to transform input data into the result collection or value.

Note

Thepredicate function is a function that takes one item as input and returns either true or false, based on whether the item satisfies some condition. They are often used conditionally to determine whether to apply certain operations in the execution chain.

Let's create some predicate functions that we can use to manipulate a collection of cars.

The All() function returns true only if all the values in the collection satisfy the predicate condition:

package predicate

func All(vals []string, predicate func(string) bool) bool {
for _, val := range vals {
if !predicate(val) {
return false
              }
       }
return true
}

The Any() function returns true as long as any one of the values in the collection satisfies the predicate condition:

funcAny(vs []string, predicate func...