anchor.diff:      | NVL
       | ROUND
       | SUM
  -    ;+    ;
  
positive.code: 
  overriding_function_spec
      : FUNCTION function_name ('(' type_elements_parameter (',' type_elements_parameter)* ')')?
        RETURN (type_spec | SELF AS RESULT) 
       (PIPELINED? (IS | AS) (DECLARE? seq_of_declare_specs? body))? ';'?
      ;
  
  
negative.code: 
  alter_table
      : ALTER TABLE tableview_name
        (
        | alter_table_properties
        | constraint_clauses
        | column_clauses
  