/*
 * Copyright (c) 2013, SRI International
 * All rights reserved.
 * Licensed under the The BSD 3-Clause License;
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 * 
 * http://opensource.org/licenses/BSD-3-Clause
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 
 * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 * 
 * Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 * 
 * Neither the name of the aic-expresso nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package com.sri.ai.grinder.library.controlflow;

import com.google.common.annotations.Beta;
import com.sri.ai.expresso.api.Expression;
import com.sri.ai.grinder.api.RewritingProcess;
import com.sri.ai.grinder.core.AbstractRewriter;
import com.sri.ai.grinder.library.Disequality;
import com.sri.ai.grinder.library.Equality;

/**
 * An atomic rewriter for rewriting expressions of the type 'if X != c then Alpha else Beta' to 'if X = c then Beta else Alpha'.
 * This is easier to read and allows for further simplifications.
 * 
 * @author braz
 *
 */
@Beta
public class DisequalityToEqualityInIfThenElseCondition extends AbstractRewriter {

	@Override
	public Expression rewriteAfterBookkeeping(Expression expression, RewritingProcess process) {
		Expression condition;
		if (IfThenElse.isIfThenElse(expression) &&
				Disequality.isDisequality(condition = IfThenElse.getCondition(expression))) {
			
			Expression equality = Equality.make(condition.getArguments());
			equality = Equality.normalize(equality, process);
			Expression thenBranch = IfThenElse.getThenBranch(expression);
			Expression elseBranch = IfThenElse.getElseBranch(expression);
			Expression result = IfThenElse.make(equality, elseBranch, thenBranch);
			return result;
		}
		return expression;
	}
}

@@ -2056,16 +2056,60 @@
 riter;%0D%0A
+import com.sri.ai.grinder.core.HasFunctor;%0D%0A
 import c
@@ -2192,16 +2192,69 @@
 uality;%0D
+%0Aimport com.sri.ai.grinder.library.FunctorConstants;%0D
 %0A%0D%0A/**%0D%0A
@@ -2571,16 +2571,151 @@
 riter %7B%0D
+%0A%09%0D%0A%09public DisequalityToEqualityInIfThenElseCondition() %7B%0D%0A%09%09this.setReifiedTests(new HasFunctor(FunctorConstants.IF_THEN_ELSE));%0D%0A%09%7D%0D
 %0A%0D%0A%09@Ove

Add reified test to newly re-enabled DisequalityToEqualityInIfThenElseCondition.