DEFINITION MODULE Files;
(* Sequential files, layered on IOChan (which wraps the runtime
   streams and files).  File is an opaque handle; NIL means the open
   failed.  Text is written/read as descriptor strings; integers as
   decimal. *)

FROM SYSTEM IMPORT ADDRESS;

TYPE FileRec;
TYPE File = POINTER TO FileRec;

PROCEDURE OpenRead(VAR name : ARRAY OF CHAR) : File;
PROCEDURE OpenWrite(VAR name : ARRAY OF CHAR) : File;
PROCEDURE Close(f : File);

PROCEDURE ReadChar(f : File) : CHAR;
PROCEDURE ReadString(f : File; VAR s : ARRAY OF CHAR);  (* one line *)
PROCEDURE ReadInt(f : File) : INTEGER;
PROCEDURE WriteChar(f : File; c : CHAR);
PROCEDURE WriteInt(f : File; n : INTEGER);
PROCEDURE WriteString(f : File; VAR s : ARRAY OF CHAR);
PROCEDURE WriteLn(f : File);

END Files.