class Champs::DecimalNumberChamp < Champ before_validation :format_value validates :value, format: { with: /\A-?[0-9]+([\.,][0-9]{1,3})?\z/, allow_nil: true, allow_blank: true, message: -> (object, _data) { # i18n-tasks-use t('errors.messages.not_a_float') object.errors.generate_message(:value, :not_a_float) } }, numericality: { allow_nil: true, allow_blank: true, message: -> (object, _data) { object.errors.generate_message(:value, :not_a_number) } }, if: :validate_champ_value_or_prefill? private def format_value return if value.blank? self.value = value.tr(",", ".").gsub(/[[:space:]]/, "") end end