gistfile1.go

package main

import "fmt"

type Array struct {
	Elems []interface{}
}

func (a *Array) push(object interface{}) {
	a.Elems = append(a.Elems, object)
}

func (a *Array) each(f func(interface{})) {
	for _, item := range a.Elems {
		f(item)
	}
}

func main() {
	items := new(Array)
	items.push("foo")

	items.each(func(item interface{}) {
		fmt.Println(item)
	})
}