Node:The Inheritance Mechanism, Next:Object Attributes, Previous:Obj Expand, Up:Obj Expand
The inheritance mechanism is based on the importation mechanism of the
Prolog module system. When an object is created, whether loaded from
file or at runtime by new/[1,2], the method predicates
(i.e. predicates implementing the methods) visible in the immediate
supers are collected. After subtracting from this set the method
predicates which are locally defined, and those that are specified in
the don't-inherit-list , the resulting set is made visible in the
module of the inheriting object by means of importation. This implies
that inherited methods are shared, expect dynamic methods.
Dynamic methods are inherited in a similar way with the big difference that they are not imported but copied. Even dynamic declarations (methods without clauses) are inherited.
Inheritance from dynamic objects differs in one aspect: Static predicates visible in a dynamic object are not imported directly from the dynamic object but from the static object from where it was imported to the dynamic object. This makes an inheriting object independent of any dynamic ancestor object after its creation.