% $Id: FamilyRules.oz,v 1.1 2007/11/26 21:15:51 leavens Exp leavens $ \insert 'FamilyExample.oz' declare proc {Son ?X ?Y} {Parent Y X} {Male X} end proc {Daughter ?X ?Y} {Parent Y X} {Female X} end proc {Parent ?Y ?X} choice {Dad Y X} [] {Mom Y X} end end