LIFO stack golang

stack.go

//Stack  Golang
package main

import "fmt"

type Element struct {
	next *Element
	val  interface{}
}

type Stack struct {
	top  *Element
	size int
}

func (stack *Stack) Len() int {
	return stack.size
}

func (stack *Stack) push(val interface{}) {
	stack.top = &Element{stack.top, val}
	stack.size++
}

func (stack *Stack) pop() interface{} {
	if stack.size > 0 {
		value := stack.top.val
		stack.top = stack.top.next
		stack.size--
		return value
	} else {
		return nil
	}

}

func main() {
	stack := new(Stack)
	stack.push(123)
	stack.push("nace")
	stack.push(1.23)
	for stack.Len() > 0 {
		fmt.Println(stack.pop())
	}
}