src/Pure/ML-Systems/polyml-5.1.ML
author wenzelm
Mon Jul 23 22:18:05 2007 +0200 (2007-07-23)
changeset 23947 5e396bcf749e
parent 23943 1b5f77bc146a
child 23966 25f34ff5eedf
permissions -rw-r--r--
added proper implementation of self_critical, CRITICAL;
     1 (*  Title:      Pure/ML-Systems/polyml-5.0.ML
     2     ID:         $Id$
     3 
     4 Compatibility wrapper for Poly/ML 5.1.
     5 *)
     6 
     7 use "ML-Systems/polyml.ML";
     8 
     9 val pointer_eq = PolyML.pointerEq;
    10 
    11 
    12 (* improved versions of use_text/file *)
    13 
    14 fun use_text name (print, err) verbose txt =
    15   let
    16     val in_buffer = ref (explode txt);
    17     val out_buffer = ref ([]: string list);
    18     fun output () = implode (rev (case ! out_buffer of "\n" :: cs => cs | cs => cs));
    19 
    20     val line_no = ref 1;
    21     fun line () = ! line_no;
    22     fun get () =
    23       (case ! in_buffer of
    24         [] => ""
    25       | c :: cs => (in_buffer := cs; if c = "\n" then line_no := ! line_no + 1 else (); c));
    26     fun put s = out_buffer := s :: ! out_buffer;
    27 
    28     fun exec () =
    29       (case ! in_buffer of
    30         [] => ()
    31       | _ => (PolyML.compilerEx (get, put, line, name) (); exec ()));
    32   in
    33     exec () handle exn => (err (output ()); raise exn);
    34     if verbose then print (output ()) else ()
    35   end;
    36 
    37 fun use_file output verbose name =
    38   let
    39     val instream = TextIO.openIn name;
    40     val txt = TextIO.inputAll instream before TextIO.closeIn instream;
    41   in use_text name output verbose txt end;
    42 
    43 
    44 
    45 (** multithreading **)
    46 
    47 open Thread;
    48 
    49 local
    50 
    51 datatype 'a result =
    52   Result of 'a |
    53   Exn of exn;
    54 
    55 fun capture f x = Result (f x) handle e => Exn e;
    56 
    57 fun release (Result y) = y
    58   | release (Exn e) = raise e;
    59 
    60 fun message s =
    61   (TextIO.output (TextIO.stdErr, (">>> " ^ s ^ "\n")); TextIO.flushOut TextIO.stdErr);
    62 
    63 
    64 val critical_lock = Mutex.mutex ();
    65 val critical_thread = ref (NONE: Thread.thread option);
    66 
    67 in
    68 
    69 (* critical section -- may be nested within the same thread *)
    70 
    71 fun self_critical () =
    72   (case ! critical_thread of
    73     NONE => false
    74   | SOME id => Thread.equal (id, Thread.self ()));
    75 
    76 fun CRITICAL e =
    77   if self_critical () then e ()
    78   else
    79     let
    80       val _ =
    81         if Mutex.trylock critical_lock then ()
    82         else
    83           (message "Waiting for critical lock";
    84            Mutex.lock critical_lock;
    85            message "Obtained critical lock");
    86       val _ = critical_thread := SOME (Thread.self ());
    87       val res = capture e ();
    88       val _ = critical_thread := NONE;
    89       val _ = Mutex.unlock critical_lock;
    90     in release res end;
    91 
    92 end;