DEFINITION MODULE InOut;

(* (C) Copyright 1987 Fitted Software Tools. All rights reserved. *)

(*
    This is the standard module InOut as defined in
    "Programming in Modula-2" by Niklaus Wirth.

    A few additionns were made to this modules, mainly
    to add support for LONGINT and LONGCARD data types
*)

FROM SYSTEM     IMPORT WORD;
FROM FileSystem IMPORT File;

CONST
    EOL = 36C;

VAR
    Done    :BOOLEAN;
    termCH  :CHAR;

(*
    Done is set to TRUE by the following procedures:
        OpenInput, OpenOutput,
        RedirectInput, RedirectOutput,
        Read,
        ReadWrd, WriteWrd,
        Read, ReadInt, ReadCard,
        ReadLongInt, ReadLongCard,
    to indicate success.
*)


PROCEDURE OpenInput( defext :ARRAY OF CHAR );
(*
    prompts the user for a file to redirect the input from.
    if the last character in the input is a '.', defext is
    appended to it.
*)

PROCEDURE OpenOutput( defext :ARRAY OF CHAR );
(*
    prompts the user for a file to redirect the input to.
    if the last character in the input is a '.', defext is
    appended to it.
*)

PROCEDURE RedirectInput( from :ARRAY OF CHAR );
(*
    redirects the input from file from.
*)

PROCEDURE RedirectOutput( to :ARRAY OF CHAR );
(*
    redirects the output to file to.
*)

PROCEDURE CloseInput;
(*
    the file opened with OpenInput or RedirectInput is closed
    and the terminal is reestablished as the input device.
*)

PROCEDURE CloseOutput;
(*
    the file opened with OpenOutput or RedirectOutput is closed
    and the terminal is reestablished as the output device.
*)

PROCEDURE Read( VAR ch :CHAR );
(*
    read a character
*)

PROCEDURE ReadString( VAR s :ARRAY OF CHAR );
(*
    read a string.
    input is terminated by a ' ', or any control character except BS or DEL.
    the terminating character is saved in termCH.
    when reading from the terminal, editing of the input is available:
        ASCII.BS deletes the last characted input
        ASCII.DEL deletes all characters input
        ASCII.ESC deletes all characters input and returns
*)

PROCEDURE ReadLine( VAR s :ARRAY OF CHAR );
(*
    read a line.
    input is terminated by an EOL, EOF or ESC character.
    the terminating character is saved in termCH.
    when reading from the terminal, editing of the input is available:
        ASCII.BS deletes the last characted input
        ASCII.DEL deletes all characters input
        ASCII.ESC deletes all characters input and returns
*)

PROCEDURE ReadInt( VAR x :INTEGER );
(*
    a string is read from the input device and is then converted to
    an INTEGER.
*)

PROCEDURE ReadCard( VAR x :CARDINAL );
(*
    a string is read from the input device and is then converted to
    a CARDINAL.
*)

PROCEDURE ReadWrd( VAR w :WORD );
(*
    read a WORD from the input file.
    legal only if input is being redirected from a file.
*)

PROCEDURE Write( ch :CHAR );
(*
    write the character
*)

PROCEDURE WriteLn;
(*
    same as: Write( ASCII.EOL )
*)

PROCEDURE WriteString( s :ARRAY OF CHAR );
(*
    write the string out
*)

PROCEDURE WriteInt( x :INTEGER; n :CARDINAL );
(*
    write the INTEGER right justified in a field of at least n characters.
*)

PROCEDURE WriteCard( x, n :CARDINAL );
(*
    write the CARDINAL right justified in a field of at least n characters.
*)

PROCEDURE WriteOct( x, n :CARDINAL );
(*
    write x in octal format in a right justified field of at least n characters.
    IF (n <= 3) AND (x < 100H) THEN 3 digits are written
    ELSE 6 digits are written
*)

PROCEDURE WriteHex( x, n :CARDINAL );
(*
    write x in hexadecimal in a right justified field of at least n characters.
    IF (n <= 2) AND (x < 100H) THEN 2 digits are written
    ELSE 4 digits are written
*)

PROCEDURE WriteWrd( w :WORD );
(*
    write w to the output file.
    only legal when output is being redirected to a file.
*)

PROCEDURE ReadLongInt( VAR x :LONGINT );
(*
    a string is read from the input device and is then converted to
    a LONGINT.
*)

PROCEDURE ReadLongCard( VAR x :LONGCARD );
(*
    a string is read from the input device and is then converted to
    a LONGCARD.
*)

PROCEDURE WriteLongInt( x :LONGINT; n :CARDINAL );
(*
    write the LONGINT right justified in a field of at least n characters.
*)

PROCEDURE WriteLongCard( x :LONGCARD; n :CARDINAL );
(*
    write the LONGCARD right justified in a field of at least n characters.
*)

END InOut.