diff --git a/main/src/com/google/refine/expr/functions/booleans/Xor.java b/main/src/com/google/refine/expr/functions/booleans/Xor.java
index fa664f00b..72fdb1e16 100644
--- a/main/src/com/google/refine/expr/functions/booleans/Xor.java
+++ b/main/src/com/google/refine/expr/functions/booleans/Xor.java
@@ -36,6 +36,7 @@ import com.google.refine.grel.Function;
 
 public class Xor implements Function {
 
+    /* naive implementation of the XOR operation */
     @Override
     public Object call(Properties bindings, Object[] args) {
         if (args.length == 2 &&