DEFINITION MODULE ProgramArgs;

  (* Access to program arguments *)

IMPORT IOChan;

TYPE
  ChanId = IOChan.ChanId;

PROCEDURE ArgChan (): ChanId;
  (* Returns a value that identifies a channel for reading
     program arguments *)

PROCEDURE IsArgPresent (): BOOLEAN;
  (* Tests if there is a current argument to read from.  If not,
     read <= IOChan.CurrentFlags() will be FALSE, and attempting
     to read from the argument channel will raise the exception
     notAvailable.
  *)

PROCEDURE NextArg ();
  (* If there is another argument, causes subsequent input from the
     argument device to come from the start of the next argument.
     Otherwise there is no argument to read from, and a call of
     IsArgPresent will return FALSE.
  *)

END ProgramArgs.