diff --git a/src/macro/Parser.yy b/src/macro/Parser.yy
index 87912f147280a147653d0b237ae46d5348a932c8..890114554835a7239d979b463fb51fa58d2ae1b8 100644
--- a/src/macro/Parser.yy
+++ b/src/macro/Parser.yy
@@ -248,7 +248,9 @@ symbol : NAME
          { $$ = make_shared<Variable>($1, driver.env, @$); }
        ;
 
-function : NAME LPAREN function_args RPAREN
+function : NAME LPAREN RPAREN
+           { $$ = make_shared<Function>($1, vector<ExpressionPtr>(), driver.env, @$); }
+         | NAME LPAREN function_args RPAREN
            { $$ = make_shared<Function>($1, $3, driver.env, @$); }
          ;