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Classification of Birds

This example illustrates how Prolog object can be used in classification of certain concepts. This style is common in expert system application for describing its domain.

animal :: {
        super(object) &
        relative_size(S) :-
                size(Obj_size),
                super(Obj_prototype),
                Obj_prototype :: size(Prototype_size),
                :(S is Obj_size/Prototype_size * 100)
                }.

bird :: {
        super(animal) &
        moving_method(fly) &
        active_at(daylight)
        }.

albatross :: {
        super(bird) &
        color(black_and_white) &
        size(115)
        }.

kiwi :: {
        super(bird) &
        moving_method(walk) &
        active_at(night) &
        size(40) &
        color(brown)
        }.

albert :: {
        super(albatross) &
        size(120)
        }.

ross :: {
        super(albatross) &
        size(40)
        }.

| ?- ross :: relative_size(R).

R = 34.78