src/HOL/Tools/Predicate_Compile/code_prolog.ML

 
 
 (* renewing the values command for Prolog queries *)
 
 val opt_print_modes =
-  Scan.optional (Parse.$$$ "(" |-- Parse.!!! (Scan.repeat1 Parse.xname --| Parse.$$$ ")")) [];
+  Scan.optional (@{keyword "("} |-- Parse.!!! (Scan.repeat1 Parse.xname --| @{keyword ")"})) [];
 
 val _ = Outer_Syntax.improper_command "values" "enumerate and print comprehensions" Keyword.diag
   (opt_print_modes -- Scan.optional (Parse.nat >> SOME) NONE -- Parse.term
    >> (fn ((print_modes, soln), t) => Toplevel.keep
         (values_cmd print_modes soln t))); (*FIXME does not preserve the previous functionality*)