(*  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 (versions 2.x and 3.x).

 *)

 open PolyML ExtendedIO;

 (*needs the Basis Library emulation*)

 use "basis.ML";

 structure String =

 struct

   fun substring (s,i,j) = StringBuiltIns.substring (s, i+1, j)

                           handle Substring => raise Subscript

   fun isPrefix s1 s2 = (s1 = substring(s2,0, size s1))

                        handle Subscript => false

 end;

 (** ML system related **)

 (** Compiler-independent timing functions **)

 (*Note start point for timing*)

 fun startTiming() = System.processtime ();

 (*Finish timing and return string*)

 fun endTiming before =

   "User + GC: " ^

   makestring (real (System.processtime () - before) / 10.0) ^

   " secs";

 (* 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;

 (** interrupts **)      (*Note: may get into race conditions*)

 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*)

 fun execute command =

   let

     val (is, os) =  ExtendedIO.execute command;

     val _ = close_out os;

     val result = input (is, 999999);

   in close_in is; result end;

 fun system cmd = (print (execute cmd); 0);	(* FIXME rc not available *)

 (* file handling *)

 (*get time of last modification*)

 fun file_info name = Int.toString (System.filedate name) handle _ => "";

 structure OS =

 struct

   structure FileSys =

   struct

     val chDir = PolyML.cd;

     fun remove name = (execute ("rm " ^ name); ());

     fun getDir () = drop_last_char (execute "pwd");

   end;

 end;

 (* getenv *)

 fun getenv var = drop_last_char

   (execute ("env | grep '^" ^ var ^ "=' | sed -e 's/" ^ var ^ "=//'"));

 end;

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

 val needs_filtered_use = true;