# File lib/parslet/bytecode/vm.rb, line 159
    def pop(n=nil)
      if n
        fail "Stack corruption detected, popping too many values (#{n}/#{@values.size})." \
          if n>@values.size
            
        @values.pop(n)
      else
        fail "Stack corruption detected, popping too many values. (stack is empty)" \
          if @values.empty?
        
        @values.pop
      end
    end