(*  Title:      Pure/ML-Systems/mosml.ML

     ID:         $Id$

     Author:     Lawrence C Paulson, Cambridge University Computer Laboratory

     Copyright   1999  University of Cambridge

 Compatibility file for Moscow ML 2.00

 NOTE: saving images does not work (yet!?), may run it interactively as follows:

 $ cd ~~/src/Pure

 $ isabelle RAW_ML_SYSTEM

 > val ml_system = "mosml";

 > use "ML-Systems/mosml.ML";

 > use "ROOT.ML";

 > Session.finish ();

 > cd "../HOL";

 > use "ROOT.ML";

 *)

 (** ML system related **)

 load "Obj";

 load "Bool";

 load "Int";

 load "Real";

 load "ListPair";

 load "OS";

 load "Process";

 load "FileSys";

 (*low-level pointer equality*)

 local val cast : 'a -> int = Obj.magic

 in fun pointer_eq (x:'a, y:'a) = (cast x = cast y) end;

 (*proper implementation available?*)

 structure IntInf =

 struct

   open Int;

 end;

 structure Real =

 struct

   open Real;

   val realFloor = real o floor;

 end;

 structure Time =

 struct

   open Time;

   fun toString t = Time.toString t

     handle Overflow => Real.toString (Time.toReal t);   (*workaround Y2004 bug*)

 end;

 structure OS =

 struct

   open OS

   structure Process = Process

   structure FileSys = FileSys

 end;

 (*limit the printing depth*)

 fun print_depth n =

  (Meta.printDepth := n div 2;

   Meta.printLength := n);

 (*interface for toplevel pretty printers, see also Pure/install_pp.ML*)

 (*the documentation refers to an installPP but I couldn't fine it!*)

 fun make_pp path pprint = ();

 fun install_pp _ = ();

 (*profiling -- dummy implementation*)

 fun profile (n: int) f x = f x;

 (*prompts -- dummy impelemtation*)

 fun ml_prompts p1 p2 = ();

 (** Compiler-independent timing functions **)

 load "Timer";

 use "ML-Systems/cpu-timer-gc.ML";

 (* bounded time execution *)

 (* FIXME proper implementation available? *)

 structure TimeLimit : sig

    exception TimeOut

    val timeLimit : Time.time -> ('a -> 'b) -> 'a -> 'b

 end = struct

    exception TimeOut

    fun timeLimit t f x =

       f x;

 end;

 (* ML command execution *)

 (*Can one redirect 'use' directly to an instream?*)

 fun use_text _ _ txt =

   let

     val tmp_name = FileSys.tmpName ();

     val tmp_file = TextIO.openOut tmp_name;

   in

     TextIO.output (tmp_file, txt);

     TextIO.closeOut tmp_file;

     use tmp_name;

     FileSys.remove tmp_name

   end;

 (** interrupts **)	(*Note: may get into race conditions*)

 (* FIXME proper implementation available? *)

 exception Interrupt;

 fun ignore_interrupt f x = f x;           

 fun raise_interrupt f x = f x;

 (** OS related **)

 (* system command execution *)

 (*execute Unix command which doesn't take any input from stdin and

   sends its output to stdout; could be done more easily by Unix.execute,

   but that function doesn't use the PATH*)

 fun execute command =

   let

     val tmp_name = FileSys.tmpName ();

     val is = (Process.system (command ^ " > " ^ tmp_name); TextIO.openIn 

 tmp_name);

     val result = TextIO.inputAll is;

   in

     TextIO.closeIn is;

     FileSys.remove tmp_name;

     result

   end;

 (*plain version; with return code*)

 fun system cmd =

   if Process.system cmd = Process.success then 0 else 1;

 (* getenv *)

 fun getenv var =

   (case Process.getEnv var of

     NONE => ""

   | SOME txt => txt);