-- file REP.adb 2:44PM  10/25/95
-- just defines procedure REP, a read-eval-print loop for expressions,
-- that takes optional parameters specifying input and output files.
-- In Ada95, that means two versions of the procedure must be defined, one
-- with two parameters, and without.

with evaluate, text_io;
use evaluate, text_io;
procedure REP is
  InFileName, OutFileName : String(1..8):= "        ";
  yes : String(1..70);
  OldIn : File_Type renames Current_Input;
  OldOut : File_Type renames Current_Output;
  NewIn, NewOut : File_Type;
  N: Natural;
begin
  put( " would you like me to go to a file for input? ");
  get_line(Yes, N);
  if Yes(1) = 'y' or Yes(1) = 'Y'
  then	put(" please supply input filename (at most 8 characters): ");
	N:= 1;
	get(InFileName(N)); 
	while not (End_Of_Line or InFileName(N)=' ' or N=8)
		loop N := N+1;
		     get(InFileName(N));
		end loop;
	new_line;
	put(" please supply output filename (at most 8 characters): ");
	N := 1;
	get(OutFileName(N));
	while not (End_Of_Line or OutFileName(N)=' ' or N=8)
		loop N := N+1;
		     get(OutFileName(N));
		end loop;
	open(NewIn, In_File, InFileName);
	set_input(NewIn); 
	create(NewOut, Out_File, OutFileName);
	set_output(NewOut);
  else put_line("please type expression to be evaluated, remember that ALL");
     put_line("tokens must be separated by spaces --- extremely dumb scanner,");
     put_line(" and variable lookups are case sensitive. ");
  end if; 	
  driver;
  if Yes(1) = 'y' or Yes(1) = 'Y'
  then	set_input(OldIn);
  	set_output(OldOut);
  	close(NewIn);
  	close(NewOut);
  end if;
end REP;