SWISH -- SWI-Prolog for SHaring

% KNOWLEDGE BASE
    % FACTS:
        % MALES
        male(abraham).
        male(clancy).
        male(mr_burns).
        male(homero).
        male(seymur_skinner).
        male(bart).
        male(milhouse).
        male(kang).
        male(santas_little_helper).
        male(snowball).

% FEMALES
        female(mona).
        female(jacqueline).
        female(marge).
        female(paty).
        female(selma).
        female(edna_krabappel).
        female(lisa).
        female(maggie).

% FATHERS
        father_of(abraham, homero).
        father_of(clancy, marge).
        father_of(clancy, paty).
        father_of(clancy, selma).
        father_of(homero, bart).
        father_of(homero, lisa).
        father_of(kang, maggie).

% MOTHERS
        mother_of(mona, homero).
        mother_of(jacqueline, marge).
        mother_of(jacqueline, paty).
        mother_of(jacqueline, selma).
        mother_of(marge, bart).
        mother_of(marge, lisa).
        mother_of(marge, maggie).

% RULES:
        % El ";" equivale al OR lógico
        % La "," equivale al AND lógico
        parent(X, Y) :- father_of(X, Y); mother_of(X, Y).
		
        child_of(X, Y) :- parent(Y, X).
        son_of(X, Y) :- child_of(X, Y), male(X).
        daughter_of(X, Y) :- child_of(X, Y), female(X).
		
		siblings(X, Y) :- parent(Z, X), parent(Z, Y), X \= Y.
		brother_of(X, Y) :- siblings(X, Y), male(X).
		sister_of(X, Y) :- siblings(X, Y), female(X).
		
		grandparent(X, Y) :- parent(X, Z), parent(Z, Y).
		grandpa(X, Y) :- grandparent(X, Y), male(X).
		grandma(X, Y) :- grandparent(X, Y), female(X).
		
		grandchild(X, Y) :- grandparent(Y, X).
		grandson(X, Y) :- grandchild(X, Y), male(X).
		granddaughter(X, Y) :- grandchild(X, Y), female(X).
		
		parent_siblings(X, Y) :- parent(Z, Y), siblings(Z, X), X \= Y.
		uncle_of(X, Y) :- parent_siblings(X, Y), male(X).
		aunt_of(X, Y) :- parent_siblings(X, Y), female(X).