call (DataMapper::Validate::NumericValidator)

    # File lib/dm-validations/numeric_validator.rb, line 16
          def call(target)
            value = target.send(field_name)
            return true if @options[:allow_nil] && value.nil?

            value = value.kind_of?(BigDecimal) ? value.to_s('F') : value.to_s

            error_message = @options[:message]
            precision     = @options[:precision]
            scale         = @options[:scale]

            if @options[:integer_only]
              return true if value =~ /\A[+-]?\d+\z/
              error_message ||= ValidationErrors.default_error_message(:not_an_integer, field_name)
            else
              # FIXME: if precision and scale are not specified, can we assume that it is an integer?
              #        probably not, as floating point numbers don't have hard
              #        defined scale. the scale floats with the length of the
              #        integral and precision. Ie. if precision = 10 and integral
              #        portion of the number is 9834 (4 digits), the max scale will
              #        be 6 (10 - 4). But if the integral length is 1, max scale
              #        will be (10 - 1) = 9, so 1.234567890.
              #        In MySQL somehow you can hard-define scale on floats. Not
              #        quite sure how that works...
              if precision && scale
                #handles both Float when it has scale specified and BigDecimal
                if precision > scale && scale > 0
                  return true if value =~ /\A[+-]?(?:\d{1,#{precision - scale}}|\d{0,#{precision - scale}}\.\d{1,#{scale}})\z/
                elsif precision > scale && scale == 0
                  return true if value =~ /\A[+-]?(?:\d{1,#{precision}}(?:\.0)?)\z/
                elsif precision == scale
                  return true if value =~ /\A[+-]?(?:0(?:\.\d{1,#{scale}})?)\z/
                else
                  raise ArgumentError, "Invalid precision #{precision.inspect} and scale #{scale.inspect} for #{field_name} (value: #{value.inspect} #{value.class})"
                end
              elsif precision && scale.nil?
                # for floats, if scale is not set

                #total number of digits is less or equal precision
                return true if value.gsub(/[^\d]/, '').length <= precision

                #number of digits before decimal == precision, and the number is x.0. same as scale = 0
                return true if value =~ /\A[+-]?(?:\d{1,#{precision}}(?:\.0)?)\z/
              else
                return true if value =~ /\A[+-]?(?:\d+|\d*\.\d+)\z/
              end
              error_message ||= ValidationErrors.default_error_message(:not_a_number, field_name)
            end

            add_error(target, error_message, field_name)

            # TODO: check the gt, gte, lt, lte, and eq options

            return false
          end