gm2-libs-pim/Termbase

DEFINITION MODULE Termbase ;

(*
   Initially the read routines from Keyboard and the
   write routine from Display is assigned to the Read,
   KeyPressed and Write procedures.
*)

EXPORT QUALIFIED ReadProcedure, StatusProcedure, WriteProcedure,
                 AssignRead, AssignWrite, UnAssignRead, UnAssignWrite,
                 Read, KeyPressed, Write ;

TYPE
ReadProcedure (type)
   ReadProcedure = PROCEDURE (VAR CHAR) ;
WriteProcedure (type)
   WriteProcedure = PROCEDURE (CHAR) ;
StatusProcedure (type)
   StatusProcedure = PROCEDURE () : BOOLEAN ;

(*
   AssignRead - assigns a read procedure and status procedure for terminal
                input. Done is set to TRUE if successful. Subsequent
                Read and KeyPressed calls are mapped onto the user supplied
                procedures. The previous read and status procedures are
                uncovered and reused after UnAssignRead is called.
*)

AssignRead
PROCEDURE AssignRead (rp: ReadProcedure; sp: StatusProcedure;
                      VAR Done: BOOLEAN) ;

(*
   UnAssignRead - undo the last call to AssignRead and set Done to TRUE
                  on success.
*)

UnAssignRead
PROCEDURE UnAssignRead (VAR Done: BOOLEAN) ;

(*
   Read - reads a single character using the currently active read
          procedure.
*)

Read
PROCEDURE Read (VAR ch: CHAR) ;

(*
   KeyPressed - returns TRUE if a character is available to be read.
*)

KeyPressed
PROCEDURE KeyPressed () : BOOLEAN ;

(*
   AssignWrite - assigns a write procedure for terminal output.
                 Done is set to TRUE if successful. Subsequent
                 Write calls are mapped onto the user supplied
                 procedure. The previous write procedure is
                 uncovered and reused after UnAssignWrite is called.
*)

AssignWrite
PROCEDURE AssignWrite (wp: WriteProcedure; VAR Done: BOOLEAN) ;

(*
   UnAssignWrite - undo the last call to AssignWrite and set Done to TRUE
                   on success.
*)

UnAssignWrite
PROCEDURE UnAssignWrite (VAR Done: BOOLEAN) ;

(*
   Write - writes a single character using the currently active write
           procedure.
*)

Write
PROCEDURE Write (VAR ch: CHAR) ;

END Termbase.