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

Functional parameters


We'll use the GetOptions() utils function as we have in previous chapters and we'll call GetOptions and InitLog in our init function so that our configuration values and logger will be set up prior to running any commands in the main package:

package main

import (
"server"
. "utils"
   "context"
   "io/ioutil"
   "net/http"
   "os"
   "os/signal"
   "time"
   "fmt"
)

func init() {
   GetOptions()
   InitLog("trace-log.txt", ioutil.Discard, os.Stdout, os.Stderr)
}

Let's subscribe to the SIGINT signal using signal Notify. Now, we can catch a Ctrl + C event before our program abruptly stops. We'll create a quit channel to hold our signal. It only needs to have a buffer size of 1.

When our quit channel receives a SIGINT signal, we can begin our graceful, orderly shutdown procedure:

func main() {
   quit := make(chan os.Signal, 1)
   signal.Notify(quit, os.Interrupt)

Pay close attention to the following code. This is where we pass our functional parameters!

newServer, err :...