diff --git a/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/rules/am/AccessMethodUtils.java b/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/rules/am/AccessMethodUtils.java
index fc0c562..f2211e6 100644
--- a/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/rules/am/AccessMethodUtils.java
+++ b/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/rules/am/AccessMethodUtils.java
@@ -110,6 +110,10 @@
         // One of the args must be a constant, and the other arg must be a variable.
         if (arg1.getExpressionTag() == LogicalExpressionTag.CONSTANT
                 && arg2.getExpressionTag() == LogicalExpressionTag.VARIABLE) {
+            // The arguments of contains() function are asymmetrical, we can only use index if it is on the first argument
+            if (funcExpr.getFunctionIdentifier() == AsterixBuiltinFunctions.CONTAINS) {
+                return false;
+            }
             ConstantExpression constExpr = (ConstantExpression) arg1;
             constFilterVal = constExpr.getValue();
             VariableReferenceExpression varExpr = (VariableReferenceExpression) arg2;
diff --git a/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/rules/am/InvertedIndexAccessMethod.java b/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/rules/am/InvertedIndexAccessMethod.java
index 6e0c1f7..fce97f4 100644
--- a/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/rules/am/InvertedIndexAccessMethod.java
+++ b/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/rules/am/InvertedIndexAccessMethod.java
@@ -71,6 +71,7 @@
 import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.visitors.VariableUtilities;
 import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.api.IInvertedIndexSearchModifierFactory;
 import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.search.ConjunctiveEditDistanceSearchModifierFactory;
+import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.search.ConjunctiveListEditDistanceSearchModifierFactory;
 import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.search.ConjunctiveSearchModifierFactory;
 import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.search.EditDistanceSearchModifierFactory;
 import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.search.JaccardSearchModifierFactory;
@@ -258,6 +259,10 @@
         ILogicalExpression nonConstArg = null;
         if (arg1.getExpressionTag() == LogicalExpressionTag.CONSTANT
                 && arg2.getExpressionTag() != LogicalExpressionTag.CONSTANT) {
+            // The arguments of edit-distance-contains() function are asymmetrical, we can only use index if it is on the first argument
+            if (funcExpr.getFunctionIdentifier() == AsterixBuiltinFunctions.EDIT_DISTANCE_CONTAINS) {
+                return false;
+            }
             constArg = arg1;
             nonConstArg = arg2;
         } else if (arg2.getExpressionTag() == LogicalExpressionTag.CONSTANT
@@ -404,6 +409,7 @@
     public boolean applyJoinPlanTransformation(Mutable<ILogicalOperator> joinRef,
             OptimizableOperatorSubTree leftSubTree, OptimizableOperatorSubTree rightSubTree, Index chosenIndex,
             AccessMethodAnalysisContext analysisCtx, IOptimizationContext context) throws AlgebricksException {
+        IOptimizableFuncExpr optFuncExpr = AccessMethodUtils.chooseFirstOptFuncExpr(chosenIndex, analysisCtx);
         // Figure out if the index is applicable on the left or right side (if both, we arbitrarily prefer the left side).
         Dataset dataset = analysisCtx.indexDatasetMap.get(chosenIndex);
         // Determine probe and index subtrees based on chosen index.
@@ -413,10 +419,13 @@
             indexSubTree = leftSubTree;
             probeSubTree = rightSubTree;
         } else if (dataset.getDatasetName().equals(rightSubTree.dataset.getDatasetName())) {
+            // The arguments of edit-distance-contains() function are asymmetrical, we can only use index if it is on the left side
+            if (optFuncExpr.getFuncExpr().getFunctionIdentifier() == AsterixBuiltinFunctions.EDIT_DISTANCE_CONTAINS) {
+                return false;
+            }
             indexSubTree = rightSubTree;
             probeSubTree = leftSubTree;
         }
-        IOptimizableFuncExpr optFuncExpr = AccessMethodUtils.chooseFirstOptFuncExpr(chosenIndex, analysisCtx);
         InnerJoinOperator join = (InnerJoinOperator) joinRef.getValue();
 
         // Remember the original probe subtree, and its primary-key variables,
@@ -898,18 +907,27 @@
                 float jaccThresh = ((AFloat) simThresh).getFloatValue();
                 return new JaccardSearchModifierFactory(jaccThresh);
             }
-            case EDIT_DISTANCE: {
+            case EDIT_DISTANCE:
+            case CONJUNCTIVE_EDIT_DISTANCE: {
                 int edThresh = ((AInt32) simThresh).getIntegerValue();
                 switch (index.getIndexType()) {
                     case SINGLE_PARTITION_NGRAM_INVIX:
                     case LENGTH_PARTITIONED_NGRAM_INVIX: {
                         // Edit distance on strings, filtered with overlapping grams.
-                        return new EditDistanceSearchModifierFactory(index.getGramLength(), edThresh);
+                        if (searchModifierType == SearchModifierType.EDIT_DISTANCE) {
+                            return new EditDistanceSearchModifierFactory(index.getGramLength(), edThresh);
+                        } else {
+                            return new ConjunctiveEditDistanceSearchModifierFactory(index.getGramLength(), edThresh);
+                        }
                     }
                     case SINGLE_PARTITION_WORD_INVIX:
                     case LENGTH_PARTITIONED_WORD_INVIX: {
                         // Edit distance on two lists. The list-elements are non-overlapping.
-                        return new ListEditDistanceSearchModifierFactory(edThresh);
+                        if (searchModifierType == SearchModifierType.EDIT_DISTANCE) {
+                            return new ListEditDistanceSearchModifierFactory(edThresh);
+                        } else {
+                            return new ConjunctiveListEditDistanceSearchModifierFactory(edThresh);
+                        }
                     }
                     default: {
                         throw new AlgebricksException("Incompatible search modifier '" + searchModifierType
@@ -917,10 +935,6 @@
                     }
                 }
             }
-            case CONJUNCTIVE_EDIT_DISTANCE: {
-                int edThresh = ((AInt32) simThresh).getIntegerValue();
-                return new ConjunctiveEditDistanceSearchModifierFactory(index.getGramLength(), edThresh);
-            }
             default: {
                 throw new AlgebricksException("Unknown search modifier type '" + searchModifierType + "'.");
             }
diff --git a/asterix-fuzzyjoin/src/main/java/edu/uci/ics/asterix/fuzzyjoin/similarity/SimilarityMetricEditDistance.java b/asterix-fuzzyjoin/src/main/java/edu/uci/ics/asterix/fuzzyjoin/similarity/SimilarityMetricEditDistance.java
index 9b9dfc6..ab60b2c 100644
--- a/asterix-fuzzyjoin/src/main/java/edu/uci/ics/asterix/fuzzyjoin/similarity/SimilarityMetricEditDistance.java
+++ b/asterix-fuzzyjoin/src/main/java/edu/uci/ics/asterix/fuzzyjoin/similarity/SimilarityMetricEditDistance.java
@@ -104,6 +104,55 @@
         }
     }
 
+    public int getSimilarityContains(IListIterator exprList, IListIterator patternList, int simThresh) {
+        int exprLen = exprList.size();
+        int patternLen = patternList.size();
+
+        // reuse existing matrix if possible
+        if (patternLen >= cols) {
+            cols = patternLen + 1;
+            matrix = new int[rows][cols];
+        }
+
+        // init matrix
+        for (int i = 0; i <= patternLen; i++) {
+            matrix[0][i] = i;
+        }
+
+        int currRow = 1;
+        int prevRow = 0;
+        int minEd = Integer.MAX_VALUE;
+        // expand dynamic programming matrix row by row
+        for (int i = 1; i <= exprLen; i++) {
+            matrix[currRow][0] = 0;
+
+            patternList.reset();
+            for (int j = 1; j <= patternLen; j++) {
+
+                matrix[currRow][j] = Math.min(Math.min(matrix[prevRow][j] + 1, matrix[currRow][j - 1] + 1),
+                        matrix[prevRow][j - 1] + (exprList.compare(patternList) == 0 ? 0 : 1));
+
+                patternList.next();
+
+                if (j == patternLen && matrix[currRow][patternLen] < minEd) {
+                    minEd = matrix[currRow][patternLen];
+                }
+            }
+
+            exprList.next();
+
+            int tmp = currRow;
+            currRow = prevRow;
+            prevRow = tmp;
+        }
+
+        if (minEd > simThresh) {
+            return -1;
+        } else {
+            return minEd;
+        }
+    }
+
     // faster implementation for common case of string edit distance
     public int UTF8StringEditDistance(byte[] bytes, int fsStart, int ssStart) {
 
@@ -215,49 +264,49 @@
     }
 
     // checks whether the first string contains a similar string to the second string
-    public int UTF8StringEditDistanceContains(byte[] bytes, int fsStart, int ssStart, int edThresh) {
+    public int UTF8StringEditDistanceContains(byte[] bytes, int stringStart, int patternStart, int edThresh) {
 
-        int fsLen = StringUtils.getStrLen(bytes, fsStart);
-        int ssLen = StringUtils.getStrLen(bytes, ssStart);
+        int stringLen = StringUtils.getStrLen(bytes, stringStart);
+        int patternLen = StringUtils.getStrLen(bytes, patternStart);
 
         // reuse existing matrix if possible
-        if (ssLen >= cols) {
-            cols = ssLen + 1;
+        if (patternLen >= cols) {
+            cols = patternLen + 1;
             matrix = new int[rows][cols];
         }
 
-        int fsDataStart = fsStart + utf8SizeIndicatorSize;
-        int ssDataStart = ssStart + utf8SizeIndicatorSize;
+        int stringDataStart = stringStart + utf8SizeIndicatorSize;
+        int patternDataStart = patternStart + utf8SizeIndicatorSize;
 
         // init matrix
-        for (int i = 0; i <= ssLen; i++) {
-            matrix[0][i] = 0;
+        for (int i = 0; i <= patternLen; i++) {
+            matrix[0][i] = i;
         }
 
         int currRow = 1;
         int prevRow = 0;
         int minEd = Integer.MAX_VALUE;
         // expand dynamic programming matrix row by row
-        int fsPos = fsDataStart;
-        for (int i = 1; i <= fsLen; i++) {
-            matrix[currRow][0] = i;
-            char fsChar = StringUtils.toLowerCase(StringUtils.charAt(bytes, fsPos));
+        int stringPos = stringDataStart;
+        for (int i = 1; i <= stringLen; i++) {
+            matrix[currRow][0] = 0;
+            char stringChar = StringUtils.toLowerCase(StringUtils.charAt(bytes, stringPos));
 
-            int ssPos = ssDataStart;
-            for (int j = 1; j <= ssLen; j++) {
-                char ssChar = StringUtils.toLowerCase(StringUtils.charAt(bytes, ssPos));
+            int patternPos = patternDataStart;
+            for (int j = 1; j <= patternLen; j++) {
+                char patternChar = StringUtils.toLowerCase(StringUtils.charAt(bytes, patternPos));
 
                 matrix[currRow][j] = Math.min(Math.min(matrix[prevRow][j] + 1, matrix[currRow][j - 1] + 1),
-                        matrix[prevRow][j - 1] + (fsChar == ssChar ? 0 : 1));
+                        matrix[prevRow][j - 1] + (stringChar == patternChar ? 0 : 1));
 
-                ssPos += StringUtils.charSize(bytes, ssPos);
+                patternPos += StringUtils.charSize(bytes, patternPos);
 
-                if (i == fsLen && matrix[currRow][j] < minEd) {
-                    minEd = matrix[currRow][j];
+                if (j == patternLen && matrix[currRow][patternLen] < minEd) {
+                    minEd = matrix[currRow][patternLen];
                 }
             }
 
-            fsPos += StringUtils.charSize(bytes, fsPos);
+            stringPos += StringUtils.charSize(bytes, stringPos);
 
             int tmp = currRow;
             currRow = prevRow;
diff --git a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/common/EditDistanceCheckEvaluator.java b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/common/EditDistanceCheckEvaluator.java
new file mode 100644
index 0000000..1db0569
--- /dev/null
+++ b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/common/EditDistanceCheckEvaluator.java
@@ -0,0 +1,107 @@
+/*
+ * Copyright 2009-2013 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package edu.uci.ics.asterix.runtime.evaluators.common;
+
+import java.io.IOException;
+
+import edu.uci.ics.asterix.builders.OrderedListBuilder;
+import edu.uci.ics.asterix.formats.nontagged.AqlSerializerDeserializerProvider;
+import edu.uci.ics.asterix.om.base.ABoolean;
+import edu.uci.ics.asterix.om.functions.AsterixBuiltinFunctions;
+import edu.uci.ics.asterix.om.types.AOrderedListType;
+import edu.uci.ics.asterix.om.types.ATypeTag;
+import edu.uci.ics.asterix.om.types.BuiltinType;
+import edu.uci.ics.asterix.om.types.EnumDeserializer;
+import edu.uci.ics.hyracks.algebricks.common.exceptions.AlgebricksException;
+import edu.uci.ics.hyracks.algebricks.runtime.base.ICopyEvaluator;
+import edu.uci.ics.hyracks.algebricks.runtime.base.ICopyEvaluatorFactory;
+import edu.uci.ics.hyracks.api.dataflow.value.ISerializerDeserializer;
+import edu.uci.ics.hyracks.data.std.api.IDataOutputProvider;
+import edu.uci.ics.hyracks.data.std.util.ArrayBackedValueStorage;
+import edu.uci.ics.hyracks.dataflow.common.data.accessors.IFrameTupleReference;
+import edu.uci.ics.hyracks.dataflow.common.data.marshalling.IntegerSerializerDeserializer;
+
+public class EditDistanceCheckEvaluator extends EditDistanceEvaluator {
+
+    protected final ICopyEvaluator edThreshEval;
+    protected int edThresh = -1;
+    protected final OrderedListBuilder listBuilder;
+    protected ArrayBackedValueStorage listItemVal;
+    @SuppressWarnings("unchecked")
+    protected final ISerializerDeserializer<ABoolean> booleanSerde = AqlSerializerDeserializerProvider.INSTANCE
+            .getSerializerDeserializer(BuiltinType.ABOOLEAN);
+    protected final static byte SER_INT32_TYPE_TAG = ATypeTag.INT32.serialize();
+    
+    public EditDistanceCheckEvaluator(ICopyEvaluatorFactory[] args, IDataOutputProvider output)
+            throws AlgebricksException {
+        super(args, output);
+        edThreshEval = args[2].createEvaluator(argOut);
+        listBuilder = new OrderedListBuilder();
+        listItemVal = new ArrayBackedValueStorage();
+    }
+
+    @Override
+    protected void runArgEvals(IFrameTupleReference tuple) throws AlgebricksException {
+        super.runArgEvals(tuple);
+        int edThreshStart = argOut.getLength();
+        edThreshEval.evaluate(tuple);
+        if (argOut.getByteArray()[edThreshStart] != SER_INT32_TYPE_TAG) {
+            throw new AlgebricksException("Invalid threshold type, expected INT32 but got "
+                    + EnumDeserializer.ATYPETAGDESERIALIZER.deserialize(argOut.getByteArray()[edThreshStart]) + ".");
+        }
+        edThresh = IntegerSerializerDeserializer.getInt(argOut.getByteArray(), edThreshStart + typeIndicatorSize);
+    }
+
+    @Override
+    protected int computeResult(byte[] bytes, int firstStart, int secondStart, ATypeTag argType)
+            throws AlgebricksException {
+        switch (argType) {
+
+            case STRING: {
+                return ed.UTF8StringEditDistance(bytes, firstStart + typeIndicatorSize, secondStart
+                        + typeIndicatorSize, edThresh);
+            }
+
+            case ORDEREDLIST: {
+                firstOrdListIter.reset(bytes, firstStart);
+                secondOrdListIter.reset(bytes, secondStart);
+                return (int) ed.getSimilarity(firstOrdListIter, secondOrdListIter, edThresh);
+            }
+
+            default: {
+                throw new AlgebricksException(AsterixBuiltinFunctions.EDIT_DISTANCE_CHECK.getName()
+                        + ": expects input type as STRING or ORDEREDLIST but got " + argType + ".");
+            }
+
+        }
+    }
+
+    @Override
+    protected void writeResult(int ed) throws IOException {
+
+        listBuilder.reset(new AOrderedListType(BuiltinType.ANY, "list"));
+        boolean matches = (ed < 0) ? false : true;
+        listItemVal.reset();
+        booleanSerde.serialize(matches ? ABoolean.TRUE : ABoolean.FALSE, listItemVal.getDataOutput());
+        listBuilder.addItem(listItemVal);
+
+        listItemVal.reset();
+        aInt32.setValue((matches) ? ed : Integer.MAX_VALUE);
+        int32Serde.serialize(aInt32, listItemVal.getDataOutput());
+        listBuilder.addItem(listItemVal);
+
+        listBuilder.write(out, true);
+    }
+}
diff --git a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/common/EditDistanceContainsEvaluator.java b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/common/EditDistanceContainsEvaluator.java
new file mode 100644
index 0000000..1dac595
--- /dev/null
+++ b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/common/EditDistanceContainsEvaluator.java
@@ -0,0 +1,53 @@
+/*
+ * Copyright 2009-2013 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package edu.uci.ics.asterix.runtime.evaluators.common;
+
+import edu.uci.ics.asterix.om.functions.AsterixBuiltinFunctions;
+import edu.uci.ics.asterix.om.types.ATypeTag;
+import edu.uci.ics.hyracks.algebricks.common.exceptions.AlgebricksException;
+import edu.uci.ics.hyracks.algebricks.runtime.base.ICopyEvaluatorFactory;
+import edu.uci.ics.hyracks.data.std.api.IDataOutputProvider;
+
+public class EditDistanceContainsEvaluator extends EditDistanceCheckEvaluator {
+    
+    public EditDistanceContainsEvaluator(ICopyEvaluatorFactory[] args, IDataOutputProvider output)
+            throws AlgebricksException {
+        super(args, output);
+    }
+
+    @Override
+    protected int computeResult(byte[] bytes, int firstStart, int secondStart, ATypeTag argType)
+            throws AlgebricksException {
+        switch (argType) {
+
+            case STRING: {
+                return ed.UTF8StringEditDistanceContains(argOut.getByteArray(), firstStart + typeIndicatorSize,
+                        secondStart + typeIndicatorSize, edThresh);
+            }
+
+            case ORDEREDLIST: {
+                firstOrdListIter.reset(bytes, firstStart);
+                secondOrdListIter.reset(bytes, secondStart);
+                return ed.getSimilarityContains(firstOrdListIter, secondOrdListIter, edThresh);
+            }
+
+            default: {
+                throw new AlgebricksException(AsterixBuiltinFunctions.EDIT_DISTANCE_CONTAINS.getName()
+                        + ": expects input type as STRING or ORDEREDLIST but got " + argType + ".");
+            }
+
+        }
+    }
+}
diff --git a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/common/EditDistanceEvaluator.java b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/common/EditDistanceEvaluator.java
index 0a5f251..7ddd957 100644
--- a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/common/EditDistanceEvaluator.java
+++ b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/common/EditDistanceEvaluator.java
@@ -20,6 +20,7 @@
 import edu.uci.ics.asterix.formats.nontagged.AqlSerializerDeserializerProvider;
 import edu.uci.ics.asterix.om.base.AInt32;
 import edu.uci.ics.asterix.om.base.AMutableInt32;
+import edu.uci.ics.asterix.om.base.ANull;
 import edu.uci.ics.asterix.om.types.ATypeTag;
 import edu.uci.ics.asterix.om.types.BuiltinType;
 import edu.uci.ics.asterix.om.types.EnumDeserializer;
@@ -49,6 +50,9 @@
     @SuppressWarnings("unchecked")
     protected final ISerializerDeserializer<AInt32> int32Serde = AqlSerializerDeserializerProvider.INSTANCE
             .getSerializerDeserializer(BuiltinType.AINT32);
+    @SuppressWarnings("unchecked")
+    private final ISerializerDeserializer<ANull> nullSerde = AqlSerializerDeserializerProvider.INSTANCE
+            .getSerializerDeserializer(BuiltinType.ANULL);
     protected ATypeTag itemTypeTag;
 
     protected int firstStart = -1;
@@ -123,10 +127,10 @@
     }
 
     protected boolean checkArgTypes(ATypeTag typeTag1, ATypeTag typeTag2) throws AlgebricksException {
-        // edit distance between null and anything else is 0
+        // edit distance between null and anything else is undefined
         if (typeTag1 == ATypeTag.NULL || typeTag2 == ATypeTag.NULL) {
             try {
-                writeResult(0);
+               nullSerde.serialize(ANull.NULL, out);
             } catch (IOException e) {
                 throw new AlgebricksException(e);
             }
diff --git a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/functions/AbstractStringContainsEval.java b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/functions/AbstractStringContainsEval.java
index ae66d22..e587f32 100644
--- a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/functions/AbstractStringContainsEval.java
+++ b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/functions/AbstractStringContainsEval.java
@@ -18,6 +18,7 @@
 
 import edu.uci.ics.asterix.formats.nontagged.AqlSerializerDeserializerProvider;
 import edu.uci.ics.asterix.om.base.ABoolean;
+import edu.uci.ics.asterix.om.base.ANull;
 import edu.uci.ics.asterix.om.types.ATypeTag;
 import edu.uci.ics.asterix.om.types.BuiltinType;
 import edu.uci.ics.asterix.om.types.EnumDeserializer;
@@ -45,6 +46,9 @@
     @SuppressWarnings("rawtypes")
     private ISerializerDeserializer boolSerde = AqlSerializerDeserializerProvider.INSTANCE
             .getSerializerDeserializer(BuiltinType.ABOOLEAN);
+    @SuppressWarnings("unchecked")
+    private final ISerializerDeserializer<ANull> nullSerde = AqlSerializerDeserializerProvider.INSTANCE
+            .getSerializerDeserializer(BuiltinType.ANULL);
 
     private final FunctionIdentifier funcID;
 
@@ -65,17 +69,9 @@
         evalString.evaluate(tuple);
 
         try {
-            if (array1.getByteArray()[0] == SER_NULL_TYPE_TAG) {
-                if (array0.getByteArray()[0] == SER_NULL_TYPE_TAG || array0.getByteArray()[0] == SER_STRING_TYPE_TAG) {
-                    boolSerde.serialize(ABoolean.TRUE, dout);
-                    return;
-                }
-            } else if (array0.getByteArray()[0] == SER_NULL_TYPE_TAG) {
-                if (array1.getByteArray()[0] == SER_STRING_TYPE_TAG) {
-                    boolSerde.serialize(ABoolean.FALSE, dout);
-                    return;
-                }
-
+            if (array0.getByteArray()[0] == SER_NULL_TYPE_TAG || array1.getByteArray()[0] == SER_NULL_TYPE_TAG) {
+                nullSerde.serialize(ANull.NULL, dout);
+                return;
             }
 
             if (array0.getByteArray()[0] != SER_STRING_TYPE_TAG || array1.getByteArray()[0] != SER_STRING_TYPE_TAG) {
diff --git a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/functions/EditDistanceCheckDescriptor.java b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/functions/EditDistanceCheckDescriptor.java
index c258f67..09ef550 100644
--- a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/functions/EditDistanceCheckDescriptor.java
+++ b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/functions/EditDistanceCheckDescriptor.java
@@ -14,28 +14,16 @@
  */
 package edu.uci.ics.asterix.runtime.evaluators.functions;
 
-import java.io.IOException;
-
-import edu.uci.ics.asterix.builders.OrderedListBuilder;
-import edu.uci.ics.asterix.formats.nontagged.AqlSerializerDeserializerProvider;
-import edu.uci.ics.asterix.om.base.ABoolean;
 import edu.uci.ics.asterix.om.functions.AsterixBuiltinFunctions;
 import edu.uci.ics.asterix.om.functions.IFunctionDescriptor;
 import edu.uci.ics.asterix.om.functions.IFunctionDescriptorFactory;
-import edu.uci.ics.asterix.om.types.AOrderedListType;
-import edu.uci.ics.asterix.om.types.ATypeTag;
-import edu.uci.ics.asterix.om.types.BuiltinType;
 import edu.uci.ics.asterix.runtime.evaluators.base.AbstractScalarFunctionDynamicDescriptor;
-import edu.uci.ics.asterix.runtime.evaluators.common.EditDistanceEvaluator;
+import edu.uci.ics.asterix.runtime.evaluators.common.EditDistanceCheckEvaluator;
 import edu.uci.ics.hyracks.algebricks.common.exceptions.AlgebricksException;
 import edu.uci.ics.hyracks.algebricks.core.algebra.functions.FunctionIdentifier;
 import edu.uci.ics.hyracks.algebricks.runtime.base.ICopyEvaluator;
 import edu.uci.ics.hyracks.algebricks.runtime.base.ICopyEvaluatorFactory;
-import edu.uci.ics.hyracks.api.dataflow.value.ISerializerDeserializer;
 import edu.uci.ics.hyracks.data.std.api.IDataOutputProvider;
-import edu.uci.ics.hyracks.data.std.util.ArrayBackedValueStorage;
-import edu.uci.ics.hyracks.dataflow.common.data.accessors.IFrameTupleReference;
-import edu.uci.ics.hyracks.dataflow.common.data.marshalling.IntegerSerializerDeserializer;
 
 public class EditDistanceCheckDescriptor extends AbstractScalarFunctionDynamicDescriptor {
 
@@ -62,73 +50,4 @@
     public FunctionIdentifier getIdentifier() {
         return AsterixBuiltinFunctions.EDIT_DISTANCE_CHECK;
     }
-
-    private static class EditDistanceCheckEvaluator extends EditDistanceEvaluator {
-
-        private final ICopyEvaluator edThreshEval;
-        private int edThresh = -1;
-        private final OrderedListBuilder listBuilder;
-        private ArrayBackedValueStorage inputVal;
-        @SuppressWarnings("unchecked")
-        private final ISerializerDeserializer<ABoolean> booleanSerde = AqlSerializerDeserializerProvider.INSTANCE
-                .getSerializerDeserializer(BuiltinType.ABOOLEAN);
-
-        public EditDistanceCheckEvaluator(ICopyEvaluatorFactory[] args, IDataOutputProvider output)
-                throws AlgebricksException {
-            super(args, output);
-            edThreshEval = args[2].createEvaluator(argOut);
-            listBuilder = new OrderedListBuilder();
-            inputVal = new ArrayBackedValueStorage();
-        }
-
-        @Override
-        protected void runArgEvals(IFrameTupleReference tuple) throws AlgebricksException {
-            super.runArgEvals(tuple);
-            int edThreshStart = argOut.getLength();
-            edThreshEval.evaluate(tuple);
-            edThresh = IntegerSerializerDeserializer.getInt(argOut.getByteArray(), edThreshStart + typeIndicatorSize);
-        }
-
-        @Override
-        protected int computeResult(byte[] bytes, int firstStart, int secondStart, ATypeTag argType)
-                throws AlgebricksException {
-            switch (argType) {
-
-                case STRING: {
-                    return ed.UTF8StringEditDistance(bytes, firstStart + typeIndicatorSize, secondStart
-                            + typeIndicatorSize, edThresh);
-                }
-
-                case ORDEREDLIST: {
-                    firstOrdListIter.reset(bytes, firstStart);
-                    secondOrdListIter.reset(bytes, secondStart);
-                    return (int) ed.getSimilarity(firstOrdListIter, secondOrdListIter, edThresh);
-                }
-
-                default: {
-                    throw new AlgebricksException(AsterixBuiltinFunctions.EDIT_DISTANCE_CHECK.getName()
-                            + ": expects input type as STRING or ORDEREDLIST but got " + argType + ".");
-                }
-
-            }
-        }
-
-        @Override
-        protected void writeResult(int ed) throws IOException {
-
-            listBuilder.reset(new AOrderedListType(BuiltinType.ANY, "list"));
-            boolean matches = (ed < 0) ? false : true;
-            inputVal.reset();
-            booleanSerde.serialize(matches ? ABoolean.TRUE : ABoolean.FALSE, inputVal.getDataOutput());
-            listBuilder.addItem(inputVal);
-
-            inputVal.reset();
-            aInt32.setValue((matches) ? ed : Integer.MAX_VALUE);
-            int32Serde.serialize(aInt32, inputVal.getDataOutput());
-            listBuilder.addItem(inputVal);
-
-            listBuilder.write(out, true);
-        }
-    }
-
 }
diff --git a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/functions/EditDistanceContainsDescriptor.java b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/functions/EditDistanceContainsDescriptor.java
index 679a9bc..d34012e 100644
--- a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/functions/EditDistanceContainsDescriptor.java
+++ b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/functions/EditDistanceContainsDescriptor.java
@@ -14,31 +14,16 @@
  */
 package edu.uci.ics.asterix.runtime.evaluators.functions;
 
-import java.io.DataOutput;
-import edu.uci.ics.asterix.builders.OrderedListBuilder;
-import edu.uci.ics.asterix.formats.nontagged.AqlSerializerDeserializerProvider;
-import edu.uci.ics.asterix.fuzzyjoin.similarity.SimilarityMetricEditDistance;
-import edu.uci.ics.asterix.om.base.ABoolean;
-import edu.uci.ics.asterix.om.base.AInt32;
-import edu.uci.ics.asterix.om.base.AMutableInt32;
 import edu.uci.ics.asterix.om.functions.AsterixBuiltinFunctions;
 import edu.uci.ics.asterix.om.functions.IFunctionDescriptor;
 import edu.uci.ics.asterix.om.functions.IFunctionDescriptorFactory;
-import edu.uci.ics.asterix.om.types.AOrderedListType;
-import edu.uci.ics.asterix.om.types.ATypeTag;
-import edu.uci.ics.asterix.om.types.BuiltinType;
-import edu.uci.ics.asterix.om.types.EnumDeserializer;
 import edu.uci.ics.asterix.runtime.evaluators.base.AbstractScalarFunctionDynamicDescriptor;
+import edu.uci.ics.asterix.runtime.evaluators.common.EditDistanceContainsEvaluator;
 import edu.uci.ics.hyracks.algebricks.common.exceptions.AlgebricksException;
 import edu.uci.ics.hyracks.algebricks.core.algebra.functions.FunctionIdentifier;
 import edu.uci.ics.hyracks.algebricks.runtime.base.ICopyEvaluator;
 import edu.uci.ics.hyracks.algebricks.runtime.base.ICopyEvaluatorFactory;
-import edu.uci.ics.hyracks.api.dataflow.value.ISerializerDeserializer;
-import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
 import edu.uci.ics.hyracks.data.std.api.IDataOutputProvider;
-import edu.uci.ics.hyracks.data.std.util.ArrayBackedValueStorage;
-import edu.uci.ics.hyracks.dataflow.common.data.accessors.IFrameTupleReference;
-import edu.uci.ics.hyracks.dataflow.common.data.marshalling.IntegerSerializerDeserializer;
 
 public class EditDistanceContainsDescriptor extends AbstractScalarFunctionDynamicDescriptor {
 
@@ -65,100 +50,4 @@
     public FunctionIdentifier getIdentifier() {
         return AsterixBuiltinFunctions.EDIT_DISTANCE_CONTAINS;
     }
-
-    private static class EditDistanceContainsEvaluator implements ICopyEvaluator {
-
-        // assuming type indicator in serde format
-        private final int typeIndicatorSize = 1;
-
-        private DataOutput out;
-        private final ArrayBackedValueStorage argOut = new ArrayBackedValueStorage();
-        private final ICopyEvaluator evalString;
-        private final ICopyEvaluator evalPattern;
-        private final ICopyEvaluator evalEdThresh;
-        private final SimilarityMetricEditDistance ed = new SimilarityMetricEditDistance();
-        private int edThresh = -1;
-        private final OrderedListBuilder listBuilder;
-        private ArrayBackedValueStorage inputVal;
-        protected final AMutableInt32 aInt32 = new AMutableInt32(-1);
-        @SuppressWarnings("unchecked")
-        private final ISerializerDeserializer<ABoolean> booleanSerde = AqlSerializerDeserializerProvider.INSTANCE
-                .getSerializerDeserializer(BuiltinType.ABOOLEAN);
-        @SuppressWarnings("unchecked")
-        private final ISerializerDeserializer<AInt32> int32Serde = AqlSerializerDeserializerProvider.INSTANCE
-                .getSerializerDeserializer(BuiltinType.AINT32);
-
-        // allowed input types
-        private final static byte SER_NULL_TYPE_TAG = ATypeTag.NULL.serialize();
-        private final static byte SER_STRING_TYPE_TAG = ATypeTag.STRING.serialize();
-        private final static byte SER_INT32_TYPE_TAG = ATypeTag.INT32.serialize();
-
-        public EditDistanceContainsEvaluator(ICopyEvaluatorFactory[] args, IDataOutputProvider output)
-                throws AlgebricksException {
-            out = output.getDataOutput();
-            evalString = args[0].createEvaluator(argOut);
-            evalPattern = args[1].createEvaluator(argOut);
-            evalEdThresh = args[2].createEvaluator(argOut);
-            listBuilder = new OrderedListBuilder();
-            inputVal = new ArrayBackedValueStorage();
-        }
-
-        @Override
-        public void evaluate(IFrameTupleReference tuple) throws AlgebricksException {
-            argOut.reset();
-            int patternStart = argOut.getLength();
-            evalString.evaluate(tuple);
-            int stringStart = argOut.getLength();
-            evalPattern.evaluate(tuple);
-            int edThreshStart = argOut.getLength();
-            evalEdThresh.evaluate(tuple);
-
-            try {
-                // edit distance between null and anything else is 0
-                if (argOut.getByteArray()[stringStart] == SER_NULL_TYPE_TAG
-                        || argOut.getByteArray()[patternStart] == SER_NULL_TYPE_TAG) {
-                    writeResult(0);
-                    return;
-                }
-
-                if (argOut.getByteArray()[stringStart] != SER_STRING_TYPE_TAG
-                        || argOut.getByteArray()[patternStart] != SER_STRING_TYPE_TAG
-                        || argOut.getByteArray()[edThreshStart] != SER_INT32_TYPE_TAG) {
-                    throw new AlgebricksException(AsterixBuiltinFunctions.EDIT_DISTANCE_CONTAINS
-                            + ": expects input type (STRING/NULL, STRING/NULL, INT), but got ("
-                            + EnumDeserializer.ATYPETAGDESERIALIZER.deserialize(argOut.getByteArray()[stringStart])
-                            + ", "
-                            + EnumDeserializer.ATYPETAGDESERIALIZER.deserialize(argOut.getByteArray()[patternStart])
-                            + ", "
-                            + EnumDeserializer.ATYPETAGDESERIALIZER.deserialize(argOut.getByteArray()[edThreshStart])
-                            + ").");
-                }
-            } catch (HyracksDataException e) {
-                throw new AlgebricksException(e);
-            }
-
-            edThresh = IntegerSerializerDeserializer.getInt(argOut.getByteArray(), edThreshStart + typeIndicatorSize);
-            int minEd = ed.UTF8StringEditDistanceContains(argOut.getByteArray(), stringStart + typeIndicatorSize,
-                    patternStart + typeIndicatorSize, edThresh);
-
-            try {
-                writeResult(minEd);
-            } catch (HyracksDataException e) {
-                throw new AlgebricksException(e);
-            }
-        }
-
-        protected void writeResult(int minEd) throws HyracksDataException {
-            boolean contains = (minEd < 0) ? false : true;
-            listBuilder.reset(new AOrderedListType(BuiltinType.ANY, "list"));
-            inputVal.reset();
-            booleanSerde.serialize(contains ? ABoolean.TRUE : ABoolean.FALSE, inputVal.getDataOutput());
-            listBuilder.addItem(inputVal);
-            inputVal.reset();
-            aInt32.setValue((contains) ? minEd : Integer.MAX_VALUE);
-            int32Serde.serialize(aInt32, inputVal.getDataOutput());
-            listBuilder.addItem(inputVal);
-            listBuilder.write(out, true);
-        }
-    }
-}
+}
\ No newline at end of file