--- a/handouts/ho02.tex	Sat Oct 05 00:36:53 2013 +0100
+++ b/handouts/ho02.tex	Sat Oct 05 00:56:06 2013 +0100
@@ -179,7 +179,14 @@
 \]
 
 \noindent
-holds, which means our algorithm satisfies the specification.
+holds, which means our algorithm satisfies the specification. This algorithm can be easily 
+extended for other regular expressions such as $r^{\{n\}}$, $r^?$, $\sim{}r$ and so on.
+
+\begin{figure}[p]
+{\lstset{language=Scala}\texttt{\lstinputlisting{../progs/app5.scala}}}
+{\lstset{language=Scala}\texttt{\lstinputlisting{../progs/app6.scala}}}
+\caption{Scala implementation of the nullable and derivatives functions.}
+\end{figure}
 
 \end{document}