anchor.diff:     ;
   
   index_params
  -   : index_elem
  -   | index_params COMMA index_elem
  +   : index_elem (COMMA index_elem)*
      ;
   
   index_elem_options
  
positive.code:    ;
  
  fdw_options
     : fdw_option
     | fdw_options fdw_option
     ;
  
  opt_fdw_options
  
negative.code:    ;
  
  attrs
     :DOT attr_name+
     ;
  
  type_name_list
     : typename (COMMA typename)*
     ;
  
  truncatestmt
  