anchor.diff:     ;
   
   xml_passing_mech
  -   : BY REF
  -   | BY VALUE_P
  +   : BY (REF | VALUE_P)
      ;
   
   within_group_clause
  
positive.code:    | RELATIVE_P a_expr
     | a_expr
     | ALL
     | FORWARD
     | FORWARD a_expr
     | FORWARD ALL
     | BACKWARD
     | BACKWARD a_expr
     | BACKWARD ALL
     ;
     //https://www.postgresql.org/docs/current/plpgsql-cursors.html#PLPGSQL-CURSOR-OPENING
  
  
negative.code:    ;
  
  decl_statement
     : decl_varname (ALIAS FOR decl_aliasitem | decl_const decl_datatype decl_collate decl_notnull decl_defval | opt_scrollable CURSOR decl_cursor_args decl_is_for decl_cursor_query) SEMI
     ;
  
  opt_scrollable
  