WorldReference.java

/**
  * This program (working title: MAS Prover) is an automated tableaux prover
  * for epistemic logic (S5n).
  * Copyright (C) 2007  Elske van der Vaart and Gert van Valkenhoef

  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 as published
  * by the Free Software Foundation.

  * This program 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 a copy of the GNU General Public License along
  * with this program; if not, write to the Free Software Foundation, Inc.,
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */

package nl.rug.ai.mas.oops.tableau;

import nl.rug.ai.mas.oops.formula.*;

public class WorldReference extends VariableReference<World>
implements World {
	public WorldReference(Variable<World> w) {
		super(w);
	}

	public NodeSubstitution match(World other) {
		NodeSubstitution ns = new NodeSubstitution();
		Substitution<World> s = ns.getWorldSubstitution();
		s.put(get(), other);
		return ns;
	}

	public World substitute(NodeSubstitution ns) {
		Substitution<World> s = ns.getWorldSubstitution();
		World w = s.get(get());
		return (w != null ? w : this);
	}

	public boolean isConcrete() {
		return false;
	}
}