Method: MapCompatibleObligation(PExp, PExp, IPOContextStack, IPogAssistantFactory)

1: /*******************************************************************************
2: *
3: *        Copyright (C) 2008 Fujitsu Services Ltd.
4: *
5: *        Author: Nick Battle
6: *
7: *        This file is part of VDMJ.
8: *
9: *        VDMJ is free software: you can redistribute it and/or modify
10: *        it under the terms of the GNU General Public License as published by
11: *        the Free Software Foundation, either version 3 of the License, or
12: *        (at your option) any later version.
13: *
14: *        VDMJ is distributed in the hope that it will be useful,
15: *        but WITHOUT ANY WARRANTY; without even the implied warranty of
16: *        MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17: *        GNU General Public License for more details.
18: *
19: *        You should have received a copy of the GNU General Public License
20: *        along with VDMJ. If not, see <http://www.gnu.org/licenses/>.
21: *
22: ******************************************************************************/
23:
24: package org.overture.pog.obligation;
25:
26: import java.util.List;
27:
28: import org.overture.ast.analysis.AnalysisException;
29: import org.overture.ast.expressions.AForAllExp;
30: import org.overture.ast.expressions.AImpliesBooleanBinaryExp;
31: import org.overture.ast.expressions.AMapDomainUnaryExp;
32: import org.overture.ast.expressions.PExp;
33: import org.overture.ast.factory.AstExpressionFactory;
34: import org.overture.ast.intf.lex.ILexNameToken;
35: import org.overture.ast.patterns.PMultipleBind;
36: import org.overture.pog.pub.IPOContextStack;
37: import org.overture.pog.pub.IPogAssistantFactory;
38: import org.overture.pog.pub.POType;
39:
40: public class MapCompatibleObligation extends ProofObligation
41: {
42:         private static final long serialVersionUID = -7453383884893058267L;
43:
44:         public MapCompatibleObligation(PExp left, PExp right, IPOContextStack ctxt,
45:                         IPogAssistantFactory af) throws AnalysisException
46:         {
47:                 super(left, POType.MAP_COMPATIBLE, ctxt, left.getLocation(), af);
48:
49:                 /**
50:                  * This obligation occurs during a map union, and ensures that if there are overlaps in the maps, then they map
51:                  * to the same thing. So m1 munion m2 produces: forall v1 in set dom m1, v2 in set dom m2 & (v1 = v2) => (m1(v1)
52:                  * = m2(v2))
53:                  */
54:
55:                 ILexNameToken ldom = getUnique("ldom");
56:                 ILexNameToken rdom = getUnique("rdom");
57:
58:                 AMapDomainUnaryExp domLeft = new AMapDomainUnaryExp();
59:                 domLeft.setExp(left.clone());
60:                 AMapDomainUnaryExp domRight = new AMapDomainUnaryExp();
61:                 domRight.setExp(right.clone());
62:                 List<PMultipleBind> bindings = getMultipleSetBindList(domLeft, ldom);
63:                 bindings.addAll(getMultipleSetBindList(domRight, rdom));
64:
65:                 AImpliesBooleanBinaryExp implies = AstExpressionFactory.newAImpliesBooleanBinaryExp(getEqualsExp(getVarExp(ldom), getVarExp(rdom)), getEqualsExp(getApplyExp(left, getVarExp(ldom)), getApplyExp(right, getVarExp(rdom))));
66:         
67:                 AForAllExp forallExp = new AForAllExp();
68:
69:                 forallExp.setBindList(bindings);
70:                 forallExp.setPredicate(implies);
71:
72:                 stitch = forallExp;
73:                 valuetree.setPredicate(ctxt.getPredWithContext(forallExp));
74:         }
75: }