diff --git a/src/org/olap4j/mdx/CallNode.java b/src/org/olap4j/mdx/CallNode.java
index 7489b87..f1bcafd 100644
--- a/src/org/olap4j/mdx/CallNode.java
+++ b/src/org/olap4j/mdx/CallNode.java
@@ -85,6 +85,9 @@ public CallNode(
         case Internal:
             assert name.startsWith("$");
             break;
+        case Empty:
+            assert name.equals("");
+            break;
         default:
             assert !name.startsWith("$")
                 && !name.equals("{}")
diff --git a/src/org/olap4j/mdx/Syntax.java b/src/org/olap4j/mdx/Syntax.java
index 2f3e6ea..60edb7d 100644
--- a/src/org/olap4j/mdx/Syntax.java
+++ b/src/org/olap4j/mdx/Syntax.java
@@ -284,7 +284,27 @@ public void unparse(
      * Defines syntax for expression invoked <code>object&#46;[&PROPERTY]</code>
      * (a variant of {@link #Property}).
      */
-    AmpersandQuotedProperty;
+    AmpersandQuotedProperty,
+
+    /**
+     * Defines the syntax for an empty expression. Empty expressions can occur
+     * within function calls, and are denoted by a pair of commas with only
+     * whitespace between them, for example
+     *
+     * <blockquote>
+     * <code>DrillDownLevelTop({[Product].[All Products]}, 3, ,
+     *  [Measures].[Unit Sales])</code>
+     * </blockquote>
+     */
+    Empty {
+        public void unparse(
+            String operatorName,
+            List<ParseTreeNode> argList,
+            ParseTreeWriter writer)
+        {
+            assert argList.size() == 0;
+        }
+    };
 
     /**
      * Converts a call to a function of this syntax into source code.
diff --git a/src/org/olap4j/mdx/parser/impl/DefaultMdxParser.cup b/src/org/olap4j/mdx/parser/impl/DefaultMdxParser.cup
index b5f6037..3ca05bb 100644
--- a/src/org/olap4j/mdx/parser/impl/DefaultMdxParser.cup
+++ b/src/org/olap4j/mdx/parser/impl/DefaultMdxParser.cup
@@ -336,6 +336,7 @@ non terminal ParseTreeNode
     case_expression,
     else_clause_opt,
     expression,
+    expression_or_empty,
     factor,
     filter_specification,
     term,
@@ -1244,6 +1245,13 @@ expression ::=
         :}
     |   value_expression
     ;
+expression_or_empty ::=
+        expression
+    |   /* empty */ {:
+            final ParseRegion region = createRegion(0, 0);
+            RESULT = new CallNode(region, "", Syntax.Empty);
+        :}
+    ;
 exp_list_opt ::=
         /* empty */ {:
             RESULT = new LinkedList();
@@ -1255,7 +1263,7 @@ exp_list ::=
             RESULT = new LinkedList();
             RESULT.add(e);
         :}
-    |   expression:e COMMA exp_list:list {:
+    |   expression_or_empty:e COMMA exp_list:list {:
             list.add(0, e); RESULT = list;
         :}
     ;
diff --git a/testsrc/org/olap4j/test/ParserTest.java b/testsrc/org/olap4j/test/ParserTest.java
index 5854bab..bd9800c 100644
--- a/testsrc/org/olap4j/test/ParserTest.java
+++ b/testsrc/org/olap4j/test/ParserTest.java
@@ -789,6 +789,37 @@ public void testIdentifier() {
         }
     }
 
+    /**
+     * Test case for empty expressions. Test case for <a href=
+  "http://sf.net/tracker/?func=detail&aid=3030772&group_id=168953&atid=848534"
+     * > bug 3030772, "DrilldownLevelTop parser error"</a>.
+     */
+    public void testEmptyExpr() {
+        assertParseQuery(
+            "select NON EMPTY HIERARCHIZE(\n"
+            + "  {DrillDownLevelTop(\n"
+            + "     {[Product].[All Products]},3,,[Measures].[Unit Sales])}"
+            + "  ) ON COLUMNS\n"
+            + "from [Sales]\n",
+            "SELECT\n"
+            + "NON EMPTY HIERARCHIZE({DrillDownLevelTop({[Product].[All Products]}, 3.0, , [Measures].[Unit Sales])}) ON COLUMNS\n"
+            + "FROM [Sales]");
+
+        // more advanced; the actual test case in the bug
+        assertParseQuery(
+            "SELECT {[Measures].[NetSales]}"
+            + " DIMENSION PROPERTIES PARENT_UNIQUE_NAME ON COLUMNS ,"
+            + " NON EMPTY HIERARCHIZE(AddCalculatedMembers("
+            + "{DrillDownLevelTop({[ProductDim].[Name].[All]}, 10, ,"
+            + " [Measures].[NetSales])}))"
+            + " DIMENSION PROPERTIES PARENT_UNIQUE_NAME ON ROWS "
+            + "FROM [cube]",
+            "SELECT\n"
+            + "{[Measures].[NetSales]} DIMENSION PROPERTIES PARENT_UNIQUE_NAME ON COLUMNS,\n"
+            + "NON EMPTY HIERARCHIZE(AddCalculatedMembers({DrillDownLevelTop({[ProductDim].[Name].[All]}, 10.0, , [Measures].[NetSales])})) DIMENSION PROPERTIES PARENT_UNIQUE_NAME ON ROWS\n"
+            + "FROM [cube]");
+    }
+
     /**
      * Parses an MDX query and asserts that the result is as expected when
      * unparsed.