content: /* 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.translator;
  
  import edu.mit.csail.sdg.alloy4.Err;
  import edu.mit.csail.sdg.alloy4.Pos;
  import edu.mit.csail.sdg.ast.Assert;
  import edu.mit.csail.sdg.ast.Expr;
  import edu.mit.csail.sdg.ast.ExprBinary;
  import edu.mit.csail.sdg.ast.ExprCall;
  import edu.mit.csail.sdg.ast.ExprConstant;
  import edu.mit.csail.sdg.ast.ExprITE;
  import edu.mit.csail.sdg.ast.ExprLet;
  import edu.mit.csail.sdg.ast.ExprList;
  import edu.mit.csail.sdg.ast.ExprQt;
  import edu.mit.csail.sdg.ast.ExprUnary;
  import edu.mit.csail.sdg.ast.ExprVar;
  import edu.mit.csail.sdg.ast.Func;
  import edu.mit.csail.sdg.ast.Sig;
  import edu.mit.csail.sdg.ast.Sig.Field;
  import edu.mit.csail.sdg.ast.VisitReturn;
  import edu.mit.csail.sdg.parser.Macro;
  
  /**
   * 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;
      }
  
      @Override
      public Expr visit(Func x) throws Err {
          return x;
      }
  
      @Override
      public Expr visit(Assert x) throws Err {
          return x;
      }
  
      @Override
      public Expr visit(Macro x) throws Err {
          return x;
      }
  
      /** {@inheritDoc} */
      @Override
      public Expr visit(Field x) {
          return x;
      }
  }
  