# File lib/hikidoc.rb, line 784
    def gets
      unless @buf.empty?
        @lineno += 1
        return @buf.pop
      end
      return nil if @eof_p   # to avoid ARGF blocking.
      line = @input.gets
      line = line.sub(/\r\n/, "\n") if line
      @eof_p = line.nil?
      @lineno += 1
      line
    end