# File lib/faster_csv.rb, line 201
      def []=(*args)
        value = args.pop

        if args.first.is_a? Integer
          if @row[args.first].nil?  # extending past the end with index
            @row[args.first] = [nil, value]
            @row.map! { |pair| pair.nil? ? [nil, nil] : pair }
          else                      # normal index assignment
            @row[args.first][1] = value
          end
        else
          index = index(*args)
          if index.nil?             # appending a field
            self << [args.first, value]
          else                      # normal header assignment
            @row[index][1] = value
          end
        end
      end