/* Alloy Analyzer 4 -- Copyright (c) 2006-2009, Felix Chang
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files
* (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify,
* merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF
* OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
package edu.mit.csail.sdg.alloy4compiler.translator;
import edu.mit.csail.sdg.alloy4.Err;
import edu.mit.csail.sdg.alloy4.Pos;
import edu.mit.csail.sdg.alloy4compiler.ast.Expr;
import edu.mit.csail.sdg.alloy4compiler.ast.ExprBinary;
import edu.mit.csail.sdg.alloy4compiler.ast.ExprList;
import edu.mit.csail.sdg.alloy4compiler.ast.ExprCall;
import edu.mit.csail.sdg.alloy4compiler.ast.ExprConstant;
import edu.mit.csail.sdg.alloy4compiler.ast.ExprITE;
import edu.mit.csail.sdg.alloy4compiler.ast.ExprLet;
import edu.mit.csail.sdg.alloy4compiler.ast.ExprQt;
import edu.mit.csail.sdg.alloy4compiler.ast.ExprUnary;
import edu.mit.csail.sdg.alloy4compiler.ast.ExprVar;
import edu.mit.csail.sdg.alloy4compiler.ast.Sig;
import edu.mit.csail.sdg.alloy4compiler.ast.VisitReturn;
import edu.mit.csail.sdg.alloy4compiler.ast.Sig.Field;
/** Immutable; this class rearranges the AST to promote as many clauses up to the top level as possible
* (in order to get better precision unsat core results)
*/
final class ConvToConjunction extends VisitReturn<Expr> {
/** {@inheritDoc} */
@Override public Expr visit(ExprBinary x) throws Err {
if (x.op == ExprBinary.Op.AND) {
Expr a = visitThis(x.left);
Expr b = visitThis(x.right);
return a.and(b);
}
return x;
}
/** {@inheritDoc} */
@Override public Expr visit(ExprQt x) throws Err {
if (x.op == ExprQt.Op.ALL) {
Expr s = x.sub.deNOP();
if (s instanceof ExprBinary && ((ExprBinary)s).op==ExprBinary.Op.AND) {
Expr a = visitThis(x.op.make(Pos.UNKNOWN, Pos.UNKNOWN, x.decls, ((ExprBinary)s).left));
Expr b = visitThis(x.op.make(Pos.UNKNOWN, Pos.UNKNOWN, x.decls, ((ExprBinary)s).right));
return a.and(b);
}
}
return x;
}
/** {@inheritDoc} */
@Override public Expr visit(ExprUnary x) throws Err {
if (x.op == ExprUnary.Op.NOOP) {
return visitThis(x.sub);
}
if (x.op == ExprUnary.Op.NOT) {
Expr s = x.sub.deNOP();
if (s instanceof ExprBinary && ((ExprBinary)s).op==ExprBinary.Op.OR) {
Expr a = visitThis(((ExprBinary)s).left.not());
Expr b = visitThis(((ExprBinary)s).right.not());
return a.and(b);
}
}
return x;
}
/** {@inheritDoc} */
@Override public Expr visit(ExprList x) { return x; }
/** {@inheritDoc} */
@Override public Expr visit(ExprCall x) { return x; }
/** {@inheritDoc} */
@Override public Expr visit(ExprConstant x) { return x; }
/** {@inheritDoc} */
@Override public Expr visit(ExprITE x) { return x; }
/** {@inheritDoc} */
@Override public Expr visit(ExprLet x) { return x; }
/** {@inheritDoc} */
@Override public Expr visit(ExprVar x) { return x; }
/** {@inheritDoc} */
@Override public Expr visit(Sig x) { return x; }
/** {@inheritDoc} */
@Override public Expr visit(Field x) { return x; }
}