The manual doesn`t explain how to get the entity patrol the path.

Code:
if(my.target == 0 && my.goal == 0)
	{
		result = path_next(my);//find nearest path
		// 
		var speed;
		path_spline(me,my.x,speed);//follow the path?
		speed += 3*time_step;
	}


Nothing happens with this code.
Aren`t there any examples somewhere?