convert

# File lib/csv/fields_converter.rb, line 41
    def convert(fields, headers, lineno)
      return fields unless need_convert?

      fields.collect.with_index do |field, index|
        if field.nil?
          field = @nil_value
        elsif field.empty?
          field = @empty_value unless @empty_value_is_empty_string
        end
        @converters.each do |converter|
          break if field.nil? and @accept_nil
          if converter.arity == 1  # straight field converter
            field = converter[field]
          else                     # FieldInfo converter
            if headers
              header = headers[index]
            else
              header = nil
            end
            field = converter[field, FieldInfo.new(index, lineno, header)]
          end
          break unless field.is_a?(String)  # short-circuit pipeline for speed
        end
        field  # final state of each field, converted or original
      end
    end