Go Programming Language For Dummies

Chapter 13

Using and Creating Packages in Go

IN THIS CHAPTER

Knowing what a package is and how it works

Using packages created by third parties

Go uses the concept of packages to better organize code for reusability and readability. In earlier chapters, I show you how to use some of the built-in packages like fmt, strconv, math, and time in your Go application. In this chapter, I dig into the topic of packages in more detail. I show you how to create your own packages for your own use, as well as create packages for sharing. Finally, I explain how to install third-party packages on your system.

Working with Packages

If you've read the earlier chapters in this book, you know that Go applications always have this first statement:

package main

Go organizes code into units call packages. A package is made up of a collection of files. The main package is a special package that contains the main() function, which makes the main package an executable program. The main() function serves as the entry point to your application.

All files in a package must be in the same directory, and all package names must all be in lowercase.

Let's take a look at an example. Suppose you have a directory ...