Golang golang-monkeypatching (snippet)

Go programming example 'golang-monkeypatching'

golang-monkeypatching

Golang beginners example: golang-monkeypatching

package main

import (
    "fmt"
)

// define the function as variable
var patchableFunc = func(i int) int {
    return i * 2
}

func testFunc() {
    // save the original func
    originalFunc := patchableFunc

    // restore the original func via defer at the end of the func
    defer func() {
        patchableFunc = originalFunc
    }()

    // call the function
    fmt.Println(patchableFunc(1))

    // change the function
    patchableFunc = func(i int) int {
        return i * 3
    }

    // call the function again
    fmt.Println(patchableFunc(2))
}

func main() {
    fmt.Println(patchableFunc(3))
    testFunc()
    fmt.Println(patchableFunc(4))
}

Useful links

• Learn Go: https://golangr.com
• Download Go: https://golang.org