# File lib/fox16/undolist.rb, line 133
    def add(command, doit=false)
      # Cut redo list
      cut

      # No command given?
      return true if command.nil?

      # Add it to the end of the undo list
      @undolist.push(command)

      # Execute it right now?
      command.redo if doit

      # Update size
      @size += command.size     # measured after redo

      # Update the mark distance
      @marker = @marker + 1 unless @marker.nil?

      # Done
      return true
    end