foreach_slice.go

package main

import (
	"fmt"
)

type slice []int
type loopFn func(int)

func (a *slice) forEach(fn loopFn) {
	for _, e := range *a {
		fn(e)
	}
}

func main() {
	a := slice{
		1, 2, 3, 4, 5, 6, 7, 8, 9,
	}
	a.forEach(func(i int) {
		fmt.Println(i)
	})
}