NativeStructure���� ��subclass : #SDL_Point�� ��layout : StructureLayout�� ��slots: { #x &=> #int. #y &=> #int}...(I got example of Ronie definition from his paper��https://hal.inria.fr/hal-01353884/document ).So all offsets logic will go to one place StructureLayout and slots. And also we will not forced to use accessors anymore.