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/*-------------------------------------------------------------------------*
* GNU Prolog *
* *
* Part : foreign facility test *
* File : new_main.pl *
* Descr.: test file *
* Author: Daniel Diaz *
* *
* Copyright (C) 1999-2015 Daniel Diaz *
* *
* This file is part of GNU Prolog *
* *
* GNU Prolog is free software: you can redistribute it and/or *
* modify it under the terms of either: *
* *
* - the GNU Lesser General Public License as published by the Free *
* Software Foundation; either version 3 of the License, or (at your *
* option) any later version. *
* *
* or *
* *
* - the GNU General Public License as published by the Free *
* Software Foundation; either version 2 of the License, or (at your *
* option) any later version. *
* *
* or both in parallel, as here. *
* *
* GNU Prolog is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU *
* General Public License for more details. *
* *
* You should have received copies of the GNU General Public License and *
* the GNU Lesser General Public License along with this program. If *
* not, see http://www.gnu.org/licenses/. *
*-------------------------------------------------------------------------*/
parent(bob, mary).
parent(jane, mary).
parent(mary, peter).
parent(paul, peter).
parent(peter, john).
anc(X, Y):-
parent(X, Y).
anc(X, Z):-
parent(X, Y),
anc(Y, Z).
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