src/Pure/ML-Systems/time_limit.ML

export just one setup function;
more antiquotations;
to_nnf: import open, avoiding internal variables (bounds);
ThmCache: added table of seen fact names;
reorganized skolem_thm/skolem_fact/saturate_skolem_cache: maintain seen fact names, ensure idempotent operation for Theory.at_end;
removed obsolete skolem attribute (NB: official fact name unavailable here);

(*  Title:      Pure/ML-Systems/time_limit.ML
    ID:         $Id$
    Author:     Makarius

Dummy implementation of NJ's TimeLimit structure.
*)

signature TIME_LIMIT =
sig
  exception TimeOut
  val timeLimit : Time.time -> ('a -> 'b) -> 'a -> 'b
end;

structure TimeLimit: TIME_LIMIT =
struct

exception TimeOut;
fun timeLimit _ f x = f x;

end;