decorator.go

package main

import (
	"fmt"
)

type Printer func (s string)

type PrinterDecorator func (Printer) Printer

func DecoratorWithStartEnd(startStr, endStr string) PrinterDecorator {
	return func (p Printer) Printer {
		return func (s string) {
			fmt.Println(startStr)
			p(s)
			fmt.Println(endStr)
		}
	}
}

func doSomething(s string) {
	fmt.Println(s)
}

func main() {
	decorator1 := DecoratorWithStartEnd("Before 1", "After 1")
	decorator1(doSomething)("Do something")
	
	decorator2 := DecoratorWithStartEnd("Before 2", "After 2")
	decorator2(doSomething)("Do something")
}