CSV::Writer#<<

# File tmp/rubies/ruby-3.3.0/lib/csv/writer.rb, line 31
def <<(row)
  case row
  when Row
    row = row.fields
  when Hash
    row = @headers.collect {|header| row[header]}
  end

  @headers ||= row if @use_headers
  @lineno += 1

  if @fields_converter
    quoted_fields = [false] * row.size
    row = @fields_converter.convert(row, nil, lineno, quoted_fields)
  end

  i = -1
  converted_row = row.collect do |field|
    i += 1
    quote(field, i)
  end
  line = converted_row.join(@column_separator) + @row_separator
  if @output_encoding
    line = line.encode(@output_encoding)
  end
  @output << line

  self
end