Class ActiveModel::Validations::FormatValidator < EachValidator

    # File activemodel/lib/active_model/validations/format.rb, line 15
15:       def check_validity!
16:         unless options.include?(:with) ^ options.include?(:without)  # ^ == xor, or "exclusive or"
17:           raise ArgumentError, "Either :with or :without must be supplied (but not both)"
18:         end
19: 
20:         check_options_validity(options, :with)
21:         check_options_validity(options, :without)
22:       end

    # File activemodel/lib/active_model/validations/format.rb, line 5
 5:       def validate_each(record, attribute, value)
 6:         if options[:with]
 7:           regexp = option_call(record, :with)
 8:           record_error(record, attribute, :with, value) if value.to_s !~ regexp
 9:         elsif options[:without]
10:           regexp = option_call(record, :without)
11:           record_error(record, attribute, :without, value) if value.to_s =~ regexp
12:         end
13:       end