src/Pure/ML-Systems/smlnj.ML

various changes including the SOME examples, rule_format and "by"

(*  Title:      Pure/ML-Systems/smlnj.ML
    ID:         $Id$
    Author:     Carsten Clasohm and Markus Wenzel, TU Muenchen

Compatibility file for Standard ML of New Jersey 110 or later.
*)

(** ML system related **)

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

val ord     = SML90.ord;
val chr     = SML90.chr;
val explode = SML90.explode;
val implode = SML90.implode;


(* New Jersey ML parameters *)

val _ =
 (Compiler.Control.Print.printLength := 1000;
  Compiler.Control.Print.printDepth := 350;
  Compiler.Control.Print.stringDepth := 250;
  Compiler.Control.Print.signatures := 2);


(* Poly/ML emulation *)

fun quit () = exit 0;

(*limit the printing depth -- divided by 2 for comparibility with Poly/ML*)
fun print_depth n =
 (Compiler.Control.Print.printDepth := n div 2;
  Compiler.Control.Print.printLength := n);


(* compiler-independent timing functions *)

(*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;


(* prompts *)

fun ml_prompts p1 p2 =
  (Compiler.Control.primaryPrompt := p1; Compiler.Control.secondaryPrompt := p2);


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

fun make_pp path pprint =
  let
    open Compiler.PrettyPrint;

    fun pp pps obj =
      pprint obj
        (add_string pps, begin_block pps INCONSISTENT,
          fn wd => add_break pps (wd, 0), fn () => add_newline pps,
          fn () => end_block pps);
  in
    (path, pp)
  end;

fun install_pp (path, pp) = Compiler.PPTable.install_pp path pp;


(* ML command execution *)

fun use_text print verbose txt =
  let
    val ref out_orig = Compiler.Control.Print.out;

    val out_buffer = ref ([]: string list);
    val out = {say = (fn s => out_buffer := s :: ! out_buffer), flush = (fn () => ())};

    fun show_output () =
      let val str = implode (rev (! out_buffer))
      in print (String.substring (str, 0, Int.max (0, size str - 1))) end;
  in
    Compiler.Control.Print.out := out;
    Compiler.Interact.useStream (TextIO.openString txt) handle exn =>
      (Compiler.Control.Print.out := out_orig; show_output (); raise exn);
    Compiler.Control.Print.out := out_orig;
    if verbose then show_output () else ()
  end;



(** interrupts **)

local

datatype 'a result =
  Result of 'a |
  Exn of exn;

fun capture f x = Result (f x) handle exn => Exn exn;

fun release (Result x) = x
  | release (Exn exn) = raise exn;


val sig_int = Signals.sigINT;
val sig_int_mask = Signals.MASK [Signals.sigINT];

fun interruptible () =
  (case Signals.masked () of
    Signals.MASKALL => false
  | Signals.MASK sigs => List.all (fn s => s <> sig_int) sigs);

val mask_signals = Signals.maskSignals;
val unmask_signals = Signals.unmaskSignals;

fun change_mask ok change unchange f x =
  if ok () then f x
  else
    let
      val _ = change sig_int_mask;
      val result = capture f x;
      val _ = unchange sig_int_mask;
    in release result end;

in


(* mask / unmask interrupt *)

fun mask_interrupt f = change_mask (not o interruptible) mask_signals unmask_signals f;
fun unmask_interrupt f = change_mask interruptible unmask_signals mask_signals f;


(* exhibit interrupt (via exception) *)

exception Interrupt;

fun exhibit_interrupt f x =
  let
    val orig_handler = Signals.inqHandler sig_int;
    fun reset_handler () = (Signals.setHandler (sig_int, orig_handler); ());

    val interrupted = ref false;

    fun set_handler cont =
      Signals.setHandler (sig_int, Signals.HANDLER (fn _ => (interrupted := true; cont)));

    fun proceed cont =
      let
        val _ = set_handler cont;
        val result = unmask_interrupt (capture f) x;
        val _ = reset_handler ();
      in release result end;
  in
    SMLofNJ.Cont.callcc proceed;
    reset_handler ();
    if ! interrupted then raise Interrupt else ()
   end;

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*)
val system = OS.Process.system: string -> int; 


(* 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);


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

val needs_filtered_use = false;