src/Pure/Syntax/parser.ML

         val nt_prods =
           fold (union (op =) o snd) (snd (Vector.sub (prods, tag))) [] @
             map prod_of_chain (these (AList.lookup (op =) chains tag));
       in map (pretty_prod name) nt_prods end;
 
-  in maps pretty_nt (sort_wrt fst (Symtab.dest tags)) end;
+  in maps pretty_nt (sort_by fst (Symtab.dest tags)) end;
 
 
 
 (** Operations on gramars **)