src/Pure/General/print_mode.ML

filtering out some package theorems

(*  Title:      Pure/General/print_mode.ML
    ID:         $Id$
    Author:     Makarius

Generic print mode -- implicit configuration for various output
mechanisms.
*)

signature BASIC_PRINT_MODE =
sig
  val print_mode: string list ref
  val print_mode_value: unit -> string list
  val print_mode_active: string -> bool
end;

signature PRINT_MODE =
sig
  include BASIC_PRINT_MODE
  val setmp: string list -> ('a -> 'b) -> 'a -> 'b
  val with_modes: string list -> ('a -> 'b) -> 'a -> 'b
end;

structure PrintMode: PRINT_MODE =
struct

val print_mode = ref ([]: string list);

fun print_mode_value () = NAMED_CRITICAL "print_mode" (fn () => ! print_mode);
fun print_mode_active s = member (op =) (print_mode_value ()) s;

fun setmp modes f x = NAMED_CRITICAL "print_mode" (fn () => Library.setmp print_mode modes f x);
fun with_modes modes f x = NAMED_CRITICAL "print_mode" (fn () => setmp (modes @ ! print_mode) f x);

end;

structure BasicPrintMode: BASIC_PRINT_MODE = PrintMode;
open BasicPrintMode;