htmlburger / carbon-fields

			$relation = strtoupper( $array[ $relation_key ] );

		}

		if ( ! in_array( $relation, $allowed_relations ) ) {

			Incorrect_Syntax_Exception::raise( 'Invalid relation type ' . $relation . '. ' .

			'The rule should be one of the following: "' . implode( '", "', $allowed_relations ) . '"' );

		}

		return $relation;

	}

			'value' => '',

		), $rule );

		if ( ! in_array( $rule['compare'], $allowed_operators ) ) {

			Incorrect_Syntax_Exception::raise( 'Invalid conditional logic compare operator: <code>' . $rule['compare'] . '</code><br>Allowed operators are: <code>' .

			implode( ', ', $allowed_operators ) . '</code>' );

			return null;

		}

		if ( in_array( $rule['compare'], $array_operators ) && ! is_array( $rule['value'] ) ) {

			Incorrect_Syntax_Exception::raise( 'Invalid conditional logic value format. An array is expected, when using the "' . $rule['compare'] . '" operator.' );