// Package stack implements a simple LIFO Stack for generic values package stack // Stack contains generic values type Stack []interface{} // New allocates a new Stack func New() Stack { return Stack{} } // Push value at tail func (s *Stack) Push(v interface{}) { *s = append(*s, v) } // Insert value at head func (s *Stack) Insert(v interface{}) { *s = append(Stack{v}, *s...) } // Pop value from tail func (s *Stack) Pop() (v interface{}) { if size := len(*s); size > 0 { v, *s = (*s)[size-1], (*s)[:size-1] } return v } // Peek a top value on Stack func (s Stack) Peek() (v interface{}) { if size := len(s); size > 0 { v = s[size-1] } return v } // Swap two top values func (s Stack) Swap() { if size := len(s); size >= 2 { s[size-1], s[size-2] = s[size-2], s[size-1] } } // Depth returns actual size of Stack func (s Stack) Depth() int { return len(s) }