decorators in go

package main

import "fmt"

// basic type of some function to change behavior
type functype func(int, int) int

// my specific function which i want to change behavior via decorator
func sum(a, b int) int {
	return a + b
}

// my decorator:
// basic sum function create new function with same type as the source
// but with new behavior: adds log message
func dec(prefix string, f functype) functype {
	return func(x, y int) int {
		res := f(x, y)
		fmt.Printf("%s: %d\n", prefix, res)
		return res
	}
}

func main() {

	// basic ussage
	r1 := sum(10, 20)
	fmt.Println(r1)

	// create new sum function by decorator
	sumWithLog := dec("suma", sum)

	// same ussage as origin, but new behavior
	r2 := sumWithLog(20, 30)
	fmt.Println(r2)
}
go