DEFINITION MODULE Terminal ;

(*
   It provides simple terminal input output
   routines which all utilize the TermBase module.
*)

EXPORT QUALIFIED Read, KeyPressed, ReadAgain, ReadString, Write,
                 WriteString, WriteLn ;


(*
   Read - reads a single character.
*)

PROCEDURE Read (VAR ch: CHAR) ;


(*
   KeyPressed - returns TRUE if a character can be read without blocking
                the caller.
*)

PROCEDURE KeyPressed () : BOOLEAN ;


(*
   ReadString - reads a sequence of characters.
                Tabs are expanded into 8 spaces and <cr> or <lf> terminates
                the string.
*)

PROCEDURE ReadString (VAR s: ARRAY OF CHAR) ;


(*
   ReadAgain - makes the last character readable again.
*)

PROCEDURE ReadAgain ;


(*
   Write - writes a single character to the Termbase module.
*)

PROCEDURE Write (ch: CHAR) ;


(*
   WriteString - writes out a string which is terminated by a <nul>
                 character or the end of string HIGH(s).
*)

PROCEDURE WriteString (s: ARRAY OF CHAR) ;


(*
   WriteLn - writes a lf character.
*)

PROCEDURE WriteLn ;


END Terminal.