(*  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 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;

(* 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);