# TITLE:
#   Stackable
#
# DESCRIPTION:
#   Stackable mixin.

# Stackable mixin provides #pop, #push, #pull, etc.
# It depends on #slice, #splice and #insert.

module Stackable

  #

  def pop
    splice(-1)
  end

  #

  def push(x)
    insert(-1,x)
  end

  #

  def pull
    slice(0)
  end

  alias :shift :pull

  #

  def poke(x)
    insert(0,x)
  end

  alias :unshift :poke

  #

  def peek
    splice(-1)
  end

end