code: private function getFunctionyTokenKinds()
      {
          static $tokens = [
              T_ARRAY,
              T_ECHO,
              T_EMPTY,
              T_EVAL,
              T_EXIT,
              T_INCLUDE,
              T_INCLUDE_ONCE,
              T_ISSET,
              T_LIST,
              T_PRINT,
              T_REQUIRE,
              T_REQUIRE_ONCE,
              T_UNSET,
              T_VARIABLE,
          ];
  
          return $tokens;
      }
docs: Gets the token kinds which can work as function calls.
  
  @return int[] Token names