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 array();

			}

			if ( in_array( $rule['compare'], array( 'IN', 'NOT IN' ) ) && ! is_array( $rule['value'] ) ) {

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

				return array();

			static::LAYOUT_TABBED_VERTICAL,

		);

		if ( ! in_array( $layout,  $available_layouts ) ) {

			$error_message = 'Incorrect layout ``' . $layout . '" specified. ' .

				'Available layouts: ' . implode( ', ', $available_layouts );

			Incorrect_Syntax_Exception::raise( $error_message );

			return $this;

		}

		$this->layout = $layout;