These are the known bugs:
\begin{enumerate}\itemsep=0pt
-\item Functors are permissable only in the main clause (object).
+\item Functors are permissible only in the main clause (object).
Therefore nesting of structures must be done using lists, not predicates
as in Prolog.
\item There is a limit to the size of strings read in (about 5000 bytes).