(*$T-*)
(*$R-*)
(****************************************************************)
(*								*)
(*	MODULA-2/86 Library					*)
(*								*)
(*	  LOGITECH SA.,  CH-1143 Apples   (Switzerland)		*)
(*								*)
(*	Module: Display						*)
(*	  Terminal driver for writing to the screen.		*)
(*	  This module is private to the Terminal Sub-System and *)
(*	  should not be used by application programs.		*)
(*								*)
(*	Version  1.05  (Aug 84)					*)
(*	  Characters are output through MS-DOS.			*)
(*	  The special characters, which are interpreted,	*)
(*	  produce code-sequences, according to ANSI standard.	*)
(*								*)
(*	(C) Copyright 1983, 1984 Logitech,  All Rights Reserved *)
(*								*)
(*	Permission is hereby granted to registered users to use *)
(*	or abstract the following program in the implementation *)
(*	of customized versions. This permission does not	*)
(*	include the right to redistribute the source code of	*)
(*	this program.						*)
(****************************************************************)

(*$T-*)
(*$R-*)
IMPLEMENTATION MODULE Display;		(* WS *)
  FROM SYSTEM IMPORT DOSCALL;
  FROM ASCII  IMPORT EOL;


  PROCEDURE Write (ch: CHAR);
  (* the following code are interpreted:
     14C = FF,  clear page, cursor home
     ASCII.EOL, go to beginning of next line (scrolls possibly)
    177C = DEL, backspace one char and clear it
  *)

  BEGIN    (* ANSI standard : *)
    IF ch = 177C THEN (* Delete *)
       DOSCALL (6, 10C); (* BackSpace *)
       DOSCALL (6, ' ');
       DOSCALL (6, 10C); (* BackSpace *)
    ELSIF ch = EOL THEN (* EOL: end of line character in Modula system *)
       DOSCALL (6, 15C);
       DOSCALL (6, 12C);
    ELSIF ch = 14C THEN (* Form Feed: clear screen *)
       DOSCALL (6, 33C);
       DOSCALL (6, '[');
       DOSCALL (6, '2');
       DOSCALL (6, 'J');
    ELSE DOSCALL (6, ch);
    END;
  END Write;

END Display.