DEFINITION MODULE RedirStdIO;

(* =========================================
  Definition and Implementation © 1993-2009
                by R. Sutcliffe
        Trinity Western University
7600 Glover Rd., Langley, BC Canada V3A 6H4
         e-mail: rsutc@twu.ca
    Last modification date 2009 12 02
=========================================== *)

IMPORT File;

PROCEDURE OpenResult () : File.FileStatus;

(* returns the result of the last attempt to open a file for redirection *)

PROCEDURE OpenOutput;
(* engages the user in a dialog to obtain a file for redirection of standard Output
    and attempts to open the file so obtained *)

PROCEDURE OpenOutputFile (VAR fileName: ARRAY OF CHAR);
(* opens the file specified by fileName for redirection of output.  If the name
    supplied is the empty string or the file could not be opened, control passes
    to OpenOutput and the filename eventually used is returned in the parameter. *)

PROCEDURE CloseOutput;
(* returns the standard output channel to the default value *)

PROCEDURE OpenInput;
(* engages the user in a dialog to obtain a file for redirection of standard Input
    and attempts to open the file so obtained *)

PROCEDURE OpenInputFile (VAR fileName: ARRAY OF CHAR);
(* Opens the file specified by fileName for redirection of input.  If the name supplied
    is the empty string or is not found, control passes to OpenInput and the filename
    eventually used is returned in the parameter. *)

PROCEDURE CloseInput;
(* returns the standard input channel to the default value *)

END RedirStdIO.