(*  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 .../Pure

 $ isabelle RAW_ML_SYSTEM

 > val ml_system = "mosml";

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

 > use "ROOT.ML";

 *)

 (** ML system related **)

 (* Poly/ML emulation *)

 load "Bool";

 load "Int";

 load "Real";

 load "ListPair";

 load "OS";

 load "Process";

 load "FileSys";

 structure OS =

   struct

   open OS

   structure Process = Process

   structure FileSys = FileSys

   end;

 (*To exit the system with an exit code -- an alternative to ^D *)

 fun exit 0 = Process.exit Process.success

   | exit _ = Process.exit Process.failure;

 (*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 _ = ();

 (*prompts*)

 (*n.a.??*)

 fun ml_prompts p1 p2 = ();

 (** Compiler-independent timing functions **)

 load "Timer";

 (*Note start point for timing*)

 fun startTiming() = 

   let val CPUtimer = Timer.startCPUTimer();

       val time = Timer.checkCPUTimer(CPUtimer)

   in  (CPUtimer,time)  end;

 (*Finish timing and return string*)

 fun endTiming (CPUtimer, {gc,sys,usr}) =

   let open Time  (*...for Time.toString, Time.+ and Time.- *)

       val {gc=gc2,sys=sys2,usr=usr2} = Timer.checkCPUTimer(CPUtimer)

   in  "User " ^ toString (usr2-usr) ^

       "  GC " ^ toString (gc2-gc) ^

       "  All "^ toString (sys2-sys + usr2-usr + gc2-gc) ^

       " secs"

       handle Time => ""

   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 mask_interrupt f x = f x;           

 fun unmask_interrupt f x = f x;

 fun exhibit_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;

 (* file handling *)

 (*get time of last modification*)

 fun file_info name = Time.toString (FileSys.modTime name) handle _ => "";

 (* getenv *)

 fun getenv var =

   (case Process.getEnv var of

     NONE => ""

   | SOME txt => txt);

 (* non-ASCII input (see also Thy/use.ML) *)

 val needs_filtered_use = false;