:- op(449,xfx,'..').

:- use_module(library(chr)).


handler   knowledge_manager.

constraints class/1,
            object/2,
            property/2.


property(Class, Prop:X), property(Class, Prop:Y) <=>
      integer(X), integer(Y), X =< Y
    | 
      property(Class, Prop:X..Y).

property(Class, Prop:X..Y), property(Class, Prop:Z) <=>
      integer(Z), Z =< X
   |
     property(Class, Prop:Z..Y).
     
property(Class, Prop:X..Y), property(Class, Prop:Z) <=>
      integer(Z), X =< Z, Z =< Y
   |
     property(Class, Prop:X..Y).


property(Class, Prop:X..Y), property(Class, Prop:Z) <=>
      integer(Z),  Y < Z
   |
     property(Class, Prop:Z..Y).

property(Class, Prop:A..B), property(Class, Prop:C..D) <=>
   min(X,A,B,C,D), max(Y,A,B,C,D)
 |
   property(Class, Prop:X..Y).

min(A,A,B,C,D):- A =< B, A =< C, A =< D.
min(B,A,B,C,D):- B =< A, B =< C, B =< D.
min(C,A,B,C,D):- C =< B, C =< A, C =< D.
min(D,A,B,C,D):- D =< B, D =< C, D =< A.

max(A,A,B,C,D):- A >= B, A >= C, A >= D.
max(B,A,B,C,D):- B >= A, B >= C, B >= D.
max(C,A,B,C,D):- C >= B, C >= A, C >= D.
max(D,A,B,C,D):- D >= B, D >= C, D >= A.



%%%%%%%%%%%%%%%%%%%%%%%%%%%

object(Obj,Class) \ property(Obj,Prop) <=> property(Class,Prop).

%Test

test:- class(man), object(john,man), object(peter,man),
       property(john,car:1), property(peter,car:3).