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

    ID:         $Id$

    Author:     Lawrence C Paulson, Cambridge University Computer Laboratory

    Copyright   1991  University of Cambridge

Compatibility file for Poly/ML (version 4.0).

*)

(** ML system related **)

(* old Poly/ML emulation *)

local

  val orig_exit = exit;

in

  open PolyML;

  val exit = orig_exit;

  fun quit () = exit 0;

end;

(* restore old-style character / string functions *)

val ord = SML90.ord;

val chr = SML90.chr;

val explode = SML90.explode;

val implode = SML90.implode;

(*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, {sys,usr}) =

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

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

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

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

      " secs"

      handle Time => ""

  end;

(* prompts *)

fun ml_prompts p1 p2 = (PolyML.Compiler.prompt1 := p1; PolyML.Compiler.prompt2 := p2);

(* toplevel pretty printing (see also Pure/install_pp.ML) *)

fun make_pp _ pprint (str, blk, brk, en) _ _ obj =

  pprint obj (str, fn ind => blk (ind, false), fn wd => brk (wd, 0),

    fn () => brk (99999, 0), en);

(* ML command execution -- 'eval' *)

local

fun drop_last [] = []

  | drop_last [x] = []

  | drop_last (x :: xs) = x :: drop_last xs;

val drop_last_char = implode o drop_last o explode;

in

fun use_text (print, err) verbose txt =

  let

    val in_buffer = ref (explode txt);

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

    fun output () = drop_last_char (implode (rev (! out_buffer)));

    fun get () =

      (case ! in_buffer of

        [] => ""

      | c :: cs => (in_buffer := cs; c));

    fun put s = out_buffer := s :: ! out_buffer;

    fun exec () =

      (case ! in_buffer of

        [] => ()

      | _ => (PolyML.compiler (get, put) (); exec ()));

  in

    exec () handle exn => (err (output ()); raise exn);

    if verbose then print (output ()) else ()

  end;

end;

(** interrupts **)

exception Interrupt = SML90.Interrupt;

local

fun capture f x = ((f x): unit; NONE) handle exn => SOME exn;

fun release NONE = ()

  | release (SOME exn) = raise exn;

val sig_int = 2;

fun change_signal new_handler f x =

  let

    (*RACE wrt. other signals*)

    val old_handler = Signal.signal (sig_int, new_handler);

    val result = capture f x;

    val _ = Signal.signal (sig_int, old_handler);

  in release result end;

val default_handler = Signal.SIG_HANDLE (fn _ => Process.interruptConsoleProcesses ());

in

val _ = Signal.signal (sig_int, default_handler);

fun ignore_interrupt f = change_signal Signal.SIG_IGN f;

fun raise_interrupt f = change_signal default_handler f;

end;

(** 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 = OS.FileSys.tmpName ();

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

    val result = TextIO.inputAll is;

  in

    TextIO.closeIn is;

    OS.FileSys.remove tmp_name;

    result

  end;

(*plain version; with return code*)

fun system cmd =

  if OS.Process.isSuccess (OS.Process.system cmd) then 0 else 1;

(* file handling *)

(*get time of last modification*)

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

(* getenv *)

fun getenv var =

  (case OS.Process.getEnv var of

    NONE => ""

  | SOME txt => txt);