/* FAMILY TREE */
/* famtree.pro */

/* by: LOUIS GUZIK Student #: 58831  Date: 9-18-93  Assignment: 1A */


/*** DATA ***/

father( orphin ).
mother( orphin, me ).

/*     CHILD , PARENT   */

father( zack, lou ).
mother( zack, kathy ).
father( lou,  louis ).
mother( lou,  flo ).
father( bruce, louis ).
mother( bruce, flo ).
father( roger, louis ).
mother( roger, flo ).
father( louis, frank ).
mother( louis, catherin ).
father( edward, frank ).
mother( edward, catherin ).
father( flo,  george ).
mother( flo,  katherin ).
father( barb, george ).
mother( barb, katherin ).

father( kathy, joe ).
mother( kathy, nancy ).
father( joey, joe ).
mother( joey, nancy ).
father( sue, joe ).
mother( sue, nancy ).
father( judy, joe ).
mother( judy, nancy ).
father( kevin, joe ).
mother( kevin, nancy ).
father( joe, james ).
mother( joe, florence ).
father( nancy, robert ).
mother( nancy, annet ).

/*  */

/*** RULES ***/

diff( X, Y ) :-	X \= Y.

parents( Child, Father, Mother ) :- father( Child, Father ),
				    mother( Child, Mother ).


parents( Child ) :- parents( Child, Father, Mother ),
		    print( '\n ', Child, '\'s father is ', Father, '.',
			   '\n ', Child, '\'s mother is ', Mother, '.' ).


parent( Child, Parent ) :- father( Child, Parent ). 
parent( Child, Parent ) :- mother( Child, Parent ).


sibiling ( Person, Sibiling ) :- diff( Person, Sibiling ), 
				 father( Person, Father1 ),
				 mother( Person, Mother1 ),
				 father( Sibiling, Father2 ),
				 mother( Sibiling, Mother2 ),
				 Father1 = Father2,
				 Mother1 = Mother2.

/*** CHECK THE FATHER ***/
ancestor( Person, Ancestor ) :- parents( Person, Father, _ ),
			 	Ancestor = Father,
				!.

/*** CHECK THE MOTHER ***/
ancestor( Person, Ancestor ) :- parents( Person, _ , Mother ),
			 	Ancestor = Mother,
				!.

/*** CHECK THE FATHER'S SIBILINGS ***/
ancestor( Person, Ancestor ) :- parents( Person, Father, _ ),
			 	father( Children, Father ),
			 	Ancestor = Children,
				!.

/*** CHECK THE MOTHER'S SIBILINGS ***/
ancestor( Person, Ancestor ) :- parents( Person, _ , Mother ),
			 	mother( Children, Mother ),
			 	Ancestor = Children,
				!.

/*** ADVANCE THE FATHER TO THE PREVIOUS GENERATION ***/
ancestor( Person, Ancestor ) :- parents( Person, Father, _ ),
			 	ancestor( Father, Ancestor ).

/*** ADVANCE THE MOTHER TO THE PREVIOUS GENERATION ***/
ancestor( Person, Ancestor ) :- parents( Person, _ , Mother ),
			 	ancestor( Mother, Ancestor).



ancestors( Child, Ancestor ) :-	father( Child, Ancestor ); /* OR */
				mother( Child, Ancestor ).

ancestors( Child, Ancestor ) :-	father( Child, Parent ); /* OR */
				mother( Child, Parent ),
				ancestors( Parent, Ancestor ).

/* END OF FAMILY TREE. */