Node:Super and Sub, Next:The Keyword Super, Previous:Use of Modules, Up:Obj Hierarchies
Two methods provided by the initial object object are
super/1 and sub/1.
(Note that any definition of super/1, except the one in
object, is transformed to super/2).
super/1 if sent to an object will return the immediate parents of
the object. sub/1 will return the immediate children of the
object if any. It is important to note that this service is provided
only for objects that have object as their initial ancestor.
| ?- john :: super(S), S :: sub(john). S = sportsman ; S = professor ; no
The sub/1 property allows programs to traverse object hierarchies from a
root object object down to the leaves.