Overview

In GO it is possible to create nested packages.  Nested packages are those packages that lie within another package. Let’s see an example

Example

Create a directory named learn. Let’s create a module with import path as “sample.com/learn” in the learn directory.

go mod init sample.com/learn

It will create a go.mod file

go.mod

module sameple.com/learn
go 1.14

Let’s create below files and directories

• learn/main.go

• learn/math/math.go

• learn/math/advanced/advanced.go

You can see that advanced is a nested package inside the math package.

learn/math/math.go

package math
func Add(a, b int) int {
return a + b
}
func Subtract(a, b int) int {
return a - b
}

learn/math/advanced/advanced.go

package advanced
func Square(a int) int {
return a * a
}

learn/main.go

package main
import (
"fmt"
"sample.com/learn/math"
"sample.com/learn/math/advanced"
)
func main() {
fmt.Println(math.Add(2, 1))
fmt.Println(math.Subtract(2, 1))
fmt.Println(advanced.Square(2))
}

Let’s run this program

learn $ go install
learn $ learn
3
1
4

Points to note about above program

• We imported the advanced package in main.go with full qualified path i.e,  import “sample.com/learn/math/advanced”

• Square function is referred to using advanced package i.e, advanced.Square(2)