diff --git a/parser/parser.yy b/parser/parser.yy
index 5973127..c8a57bd 100644
--- a/parser/parser.yy
+++ b/parser/parser.yy
@@ -99,7 +99,9 @@ program: program_items {
        }
        ;
 
-program_items: /* empty */
+program_items: /* empty */ {
+                $$ = new ItemsNode();
+             }
              | program_item program_items {
                 $$ = new ItemsNode();
                 $$->addChild($1);
@@ -138,7 +140,9 @@ function: IDENTIFIER LPAREN parameter_list RPAREN COLON type LCURLY function_ite
         }
         ;
 
-function_items: /* empty */
+function_items: /* empty */ {
+                $$ = new ItemsNode();
+              }
               | statement function_items {
                 $$ = new ItemsNode();
                 $$->addChild($1);
@@ -146,7 +150,9 @@ function_items: /* empty */
               }
               ;
 
-parameter_list: /* empty */
+parameter_list: /* empty */ {
+                $$ = new ItemsNode();
+              }
               | variable_spec parameter_list_more {
                 $$ = new ItemsNode();
                 $$->addChild($1);
@@ -154,7 +160,9 @@ parameter_list: /* empty */
               }
               ;
 
-parameter_list_more: /* empty */
+parameter_list_more: /* empty */ {
+                    $$ = new ItemsNode();
+                   }
                    | COMMA variable_spec parameter_list_more {
                     $$ = new ItemsNode();
                     $$->addChild($2);
@@ -200,7 +208,9 @@ struct_type: STRUCT LCURLY struct_items RCURLY {
            }
            ;
 
-struct_items: /* empty */
+struct_items: /* empty */ {
+                $$ = new ItemsNode();
+            }
             | struct_item struct_items {
                 $$ = new ItemsNode();
                 $$->addChild($1);