diff --git a/raco/myrial/parser.py b/raco/myrial/parser.py
index 47f97166..8ccc0349 100644
--- a/raco/myrial/parser.py
+++ b/raco/myrial/parser.py
@@ -234,7 +234,26 @@ def check_name(name):
         Parser.decomposable_aggs[logical] = da
 
     @staticmethod
-    def add_udf(p, name, args, body_expr):
+    def add_nary_udf(p, name, args, emitters):
+        """Add an n-ary user-defined function to the global function table.
+
+        :param p: The parser context
+        :param name: The name of the function
+        :type name: string
+        :param args: A list of function arguments
+        :type args: list of strings
+        :param emitter: The output expression(s)
+        :type body_expr: A list of NaryEmitArg instances
+        """
+        if not all(isinstance(e, emitarg.NaryEmitArg) for e in emitters):
+            raise IllegalWildcardException(name, p.lineno(0))
+        if sum(len(x.sexprs) for x in emitters) != len(emitters):
+            raise NestedTupleExpressionException(p.lineno(0))
+        emit_exprs = [e.sexprs[0] for e in emitters]
+        Parser.add_udf(p, name, args, emit_exprs)
+
+    @staticmethod
+    def add_udf(p, name, args, body_exprs):
         """Add a user-defined function to the global function table.
 
         :param p: The parser context
@@ -242,8 +261,8 @@ def add_udf(p, name, args, body_expr):
         :type name: string
         :param args: A list of function arguments
         :type args: list of strings
-        :param body_expr: A scalar expression containing the function body
-        :type body_expr: raco.expression.Expression
+        :param body_exprs: A list of scalar expressions containing the body
+        :type body_exprs: list of raco.expression.Expression
         """
         if name in Parser.udf_functions:
             raise DuplicateFunctionDefinitionException(name, p.lineno(0))
@@ -251,9 +270,15 @@ def add_udf(p, name, args, body_expr):
         if len(args) != len(set(args)):
             raise DuplicateVariableException(name, p.lineno(0))
 
-        Parser.check_for_undefined(p, name, body_expr, args)
+        if len(body_exprs) == 1:
+            emit_op = body_exprs[0]
+        else:
+            emit_op = TupleExpression(body_exprs)
+
+        Parser.check_for_undefined(p, name, emit_op, args)
 
-        Parser.udf_functions[name] = Function(args, body_expr)
+        Parser.udf_functions[name] = Function(args, emit_op)
+        return emit_op
 
     @staticmethod
     def mangle(name):
@@ -355,13 +380,19 @@ def p_unreserved_id_list(p):
     @staticmethod
     def p_udf(p):
         """udf : DEF unreserved_id LPAREN optional_arg_list RPAREN COLON sexpr SEMI"""  # noqa
-        Parser.add_udf(p, p[2], p[4], p[7])
+        Parser.add_udf(p, p[2], p[4], [p[7]])
+        p[0] = None
+
+    @staticmethod
+    def p_nary_udf(p):
+        """udf : DEF unreserved_id LPAREN optional_arg_list RPAREN COLON table_literal SEMI"""  # noqa
+        Parser.add_nary_udf(p, p[2], p[4], p[7])
         p[0] = None
 
     @staticmethod
     def p_constant(p):
         """constant : CONST unreserved_id COLON sexpr SEMI"""
-        Parser.add_udf(p, p[2], [], p[4])
+        Parser.add_udf(p, p[2], [], [p[4]])
         p[0] = None
 
     @staticmethod
diff --git a/raco/myrial/query_tests.py b/raco/myrial/query_tests.py
index b4cc371a..18f5efbb 100644
--- a/raco/myrial/query_tests.py
+++ b/raco/myrial/query_tests.py
@@ -1245,6 +1245,52 @@ def test_duplicate_variable_udf(self):
         with self.assertRaises(DuplicateVariableException):
             self.check_result(query, collections.Counter())
 
+    def test_nary_udf(self):
+        query = """
+        DEF Foo(a,b): [a + b, a - b];
+
+        out = [FROM SCAN(%s) AS X EMIT id, Foo(salary, dept_id) as [x, y]];
+        STORE(out, OUTPUT);
+        """ % self.emp_key
+
+        expected = collections.Counter([(t[0], t[1] + t[3], t[3] - t[1])
+                                        for t in self.emp_table])
+        self.check_result(query, expected)
+
+    def test_nary_udf_name_count(self):
+        query = """
+        DEF Foo(a,b): [a + b, a - b];
+
+        out = [FROM SCAN(%s) AS X EMIT id, Foo(salary, dept_id) as [x, y, z]];
+        STORE(out, OUTPUT);
+        """ % self.emp_key
+
+        with self.assertRaises(IllegalColumnNamesException):
+            self.check_result(query, None)
+
+    def test_nary_udf_illegal_nesting(self):
+        query = """
+        DEF Foo(x): [x + 3, x - 3];
+        DEF Bar(a,b): [Foo(x), Foo(b)];
+
+        out = [FROM SCAN(%s) AS X EMIT id, Bar(salary, dept_id) as [x, y]];
+        STORE(out, OUTPUT);
+        """ % self.emp_key
+
+        with self.assertRaises(NestedTupleExpressionException):
+            self.check_result(query, None)
+
+    def test_nary_udf_illegal_wildcard(self):
+        query = """
+        DEF Foo(x): [x + 3, *];
+
+        out = [FROM SCAN(%s) AS X EMIT id, Foo(salary, dept_id) as [x, y]];
+        STORE(out, OUTPUT);
+        """ % self.emp_key
+
+        with self.assertRaises(IllegalWildcardException):
+            self.check_result(query, None)
+
     def test_triangle_udf(self):
         query = """
         DEF Triangle(a,b): (a*b)//2;