public function define(
		$app_name,
		$ext_name,
		callable $app_func = null,
		callable $ext_func = null,
		$app_args = [],
		$ext_args = []
	) {
		$this->definitions[self::EXT][$app_name] = [
			self::DEFINITION_KEY  => $ext_name,
			self::DEFINITION_MAP  => $app_name,
			self::DEFINITION_FUNC => $ext_func,
			self::DEFINITION_ARGS => $ext_args
		];
		$this->definitions[self::APP][$ext_name] = [
			self::DEFINITION_KEY  => $app_name,
			self::DEFINITION_MAP  => $ext_name,
			self::DEFINITION_FUNC => $app_func,
			self::DEFINITION_ARGS => $app_args,
		];
	}
public function define(
		$app_name,
		$ext_name,
		callable $app_func = null,
		callable $ext_func = null,
		$app_args = [],
		$ext_args = []
	) {
		$this->definitions[self::EXT][$app_name] = [
			self::DEFINITION_KEY  => $ext_name,
			self::DEFINITION_MAP  => $app_name,
			self::DEFINITION_FUNC => $ext_func,
			self::DEFINITION_ARGS => $ext_args
		];
		$this->definitions[self::APP][$ext_name] = [
			self::DEFINITION_KEY  => $app_name,
			self::DEFINITION_MAP  => $ext_name,
			self::DEFINITION_FUNC => $app_func,
			self::DEFINITION_ARGS => $app_args,
		];
	}
public function define ( $ app_name , $ ext_name , callable $ app_func = null , callable $ ext_func = null , $ app_args = [ ] , $ ext_args = [ ] ) { $ this -> definitions [ self :: EXT ] [ $ app_name ] = [ self :: DEFINITION_KEY => $ ext_name , self :: DEFINITION_MAP => $ app_name , self :: DEFINITION_FUNC => $ ext_func , self :: DEFINITION_ARGS => $ ext_args ] ; $ this -> definitions [ self :: APP ] [ $ ext_name ] = [ self :: DEFINITION_KEY => $ app_name , self :: DEFINITION_MAP => $ ext_name , self :: DEFINITION_FUNC => $ app_func , self :: DEFINITION_ARGS => $ app_args , ] ; }
Saves field definitions.

@param string   $app_name Property name in application context.
@param string   $ext_name Property name storage context.
@param callable $app_func Callable for transforming property to app context.
@param callable $ext_func Callable for transforming property to storage context.
@param array    $app_args Arguments for app callback.
@param array    $ext_args Arguments for storage callback.
Saves field definitions .