Implementing a stack using a slice

A surprisingly common use of a slice is to implement a stack. Here is how it is done.

How to do it...

A stack push is simply append:

// A generic stack of type T
type Stack[T any] []T
func (s *Stack[T]) Push(val T) {
     *s = append(*s, val)
}

To implement pop, truncate the slice:

func (s *Stack[T]) Pop() (val T) {
     val = (*s)[len(*s)-1]
     *s = (*s)[:len(*s)-1]
     return
}

Again, note the use of parentheses and indirections. We cannot write *s[len(*s)-1], because that is interpreted as *(s[len(*s)-1]. To prevent that, we have (*s).