# File lib/kwartz/parser.rb, line 71
    def reset(input, filename='')
      input  or raise ArgumentError.new("#{self.class.name}#reset() requires string argument.")
      @input   = input
      @filename = filename
      @linenum = 1       # 1 start
      @column  = 0       # 1 start
      @pos     = -1      # 0 start
      @max_pos = @input.length - 1
      @token   = nil
      @value   = nil
      @error   = nil
      @ch      = nil
      getch()
    end