src/Pure/POLY.ML

fixed a bug in POLY.ML: delete_file didn't close streams;
added function pwd to get current working directory

(*  Title:      Pure/POLY
    ID:         $Id$
    Author:     Lawrence C Paulson, Cambridge University Computer Laboratory
    Copyright   1991  University of Cambridge

Compatibility file for Poly/ML (AHL release 1.88)
*)

open PolyML ExtendedIO;


(*A conditional timing function: applies f to () and, if the flag is true,
  prints its runtime.*)

fun cond_timeit flag f =
  if flag then
    let val before = System.processtime()
        val result = f()
        val both = real(System.processtime() - before) / 10.0
    in  output(std_out, "Process time (incl GC): "^
                         makestring both ^ " secs\n");
        result
    end
  else f();


(*Save function: in Poly/ML, ignores filename and commits to present file*)

fun xML filename banner = commit();


(*Interface for toplevel pretty printers, 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);


(*** File handling ***)

local

(*These are functions from library.ML *)
fun take_suffix _ [] = ([], [])
  | take_suffix pred (x :: xs) =
      (case take_suffix pred xs of
         ([], sffx) => if pred x then ([], x :: sffx)
                                 else ([x], sffx)
       | (prfx, sffx) => (x :: prfx, sffx));

fun apr (f,y) x = f(x,y);

in

(*Get a string containing the time of last modification, attributes, owner
  and size of file (but not the path) *)
fun file_info "" = ""
  | file_info name =
      let
          val (is, os) = ExtendedIO.execute ("ls -l " ^ name)
          val (result, _) = take_suffix (apr(op<>," ")) 
                              (explode (ExtendedIO.input_line is))
             (*Remove the part after the last " " (i.e. the path/filename) *)
        in close_in is;
           close_out os;
           implode result
        end;

(*Delete a file *)
fun delete_file name =
  let val (is, os) = ExtendedIO.execute ("rm " ^ name)
  in close_in is;
     close_out os
  end;

(*Get pathname of current working directory *)
fun pwd () =
  let val (is, os) = ExtendedIO.execute ("pwd")
      val (path, _) = take_suffix (apr(op=,"\n"))
                       (explode (ExtendedIO.input_line is)) (*remove newline *)
  in close_in is;
     close_out os;
     implode path
  end;

end;