% 
% Author: Alex Roque
% Assignment #: 1
% Due Date: 09/13/01
% Program Title: Assignment 1
% Program Description: This assignment writes the predicate half_sibling,
% print_half_siblings, grandmother, print_grandmothers, exes(X,Y), and print_exes
%
% I certify that this is my work and have not consulted with anyone else.
%
%
%
%

%	CLAUSES

% the parent clauses
% parent(X,Y) means that X is a (biological) parent of Y.

parent(bill,cathy).
parent(mark,ann).
parent(cathy, chris).
parent(ray,alex).
parent(mark,susan).
parent(michelle,ann).
parent(becky,susan).
parent(david,mark).
parent(mona,mark).
parent(david,nina).
parent(mona,nina).
parent(ray,sophia).
parent(michelle,jill).
parent(john,jill).


% the sex clause
% sex(X,Y) means that the sex of X is Y

sex(bill,male).
sex(cathy,female).
sex(mark,male).
sex(chris,male).
sex(ray,male).
sex(alex,male).
sex(susan,female).
sex(mona,female).
sex(nina,female).
sex(sophia,female).
sex(ann,female).
sex(becky,female).
sex(susan,female).
sex(david,male).
sex(john,male).
sex(jill,female).
sex(michelle,female).

%%%%%%%%%%%%%%%%		HALF SIBLINGS BLOCK

% X is the half-sibling of Y if X and Y have a common parent, but the other one is different.
half_sibling(X,Y) :-
	parent(Parent1,X),
	parent(Parent1,Y),
	parent(Parent2,X),
	parent(Parent3,Y),
	Parent1\==Parent2,
	Parent1\==Parent3,
	Parent2\==Parent3.

% This is a loop that prints all half-siblings.
print_half_siblings :-
	nl, nl, tab(10),
        write(' HALF SIBLING LIST'),
        nl, tab(10),  
        write('==================='),
        nl, nl, print_all_half_siblings.

print_all_half_siblings :-
        half_sibling(X,Y),
        write(X),
	write(' is half sibling of '),
	write(Y),
        nl, fail.
print_all_half_siblings.

%%%%%%%%%%%%%%%%		END HALF SIBLINGS

%%%%%%%%%%%%%%%%		ABUELAS!

% X is a grandmother of Y if X is a female, and  X is the parent of Z, which is the parent of Y.
grandmother(X,Y) :-
	sex(X,female),
	parent(X,Z),
	parent(Z,Y).

% This is a loop that prints all grandmothers.
print_grandmothers :-
	nl, nl, tab(10),
	write(' GRANDMOTHER LIST'),
	nl, tab(10),
	write('=================='),
	nl, nl, print_all_grandmothers.

print_all_grandmothers :-
	grandmother(X,Y),
	write(X),
	write(' is the grandmother of '),
	write(Y),
	write('.'),
	nl, fail.
print_all_grandmothers.

%%%%%%%%%%%%%%%%%		END OF ABUELAS!


%%%%%%%%%%%%%%%%%		EXES


% X and Y are exes if they are married to different people and they have a child together.
exes(X,Y) :-
	half_sibling(A,B),
	parent(X,A),
	parent(Y,B),
	sex(X,_Sex1),
	sex(Y,_Sex2),
	X\==Y,
	parent(X,D),
	parent(Y,E),
	D\==E,
	D\==A,
	E\==B.

% This is a loop that prints all exes.
print_exes :-
        nl, nl, tab(10),
        write(' EXES LIST'),
        nl, tab(10),
        write('==========='),
        nl, nl, print_all_exes.
        
print_all_exes :-
        exes(X,Y),
        write(X),
        write(' is an ex of '),
        write(Y),
        write('.'),
        nl, fail.
print_all_exes.
%%%%%%%%%%%%%%%%		END OF EXES

go:- print_grandmothers,print_half_siblings,print_exes.