161 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

   162 \begin{frame}[t,fragile]

   163 

   164 \small

   165 \begin{textblock}{13}(-0.5,1)

   166 \begin{lstlisting}[numbers=none]

   167 def mkeps(r: Rexp) : Val = r match {

   168   ...

   169   case PLUS(r) => Stars(List(mkeps(r))) 

   170   case OPTIONAL(r) => Stars(Nil)

   171   case NTIMES(r, n) => Stars(List.fill(n)(mkeps(r)))

   172 }

   173 

   174 def inj(r: Rexp, c: Char, v: Val) : Val = (r, v) match {

   175   ...

   176   case (RANGE(_), Empty) => Chr(c)

   177   case (PLUS(r), Sequ(v1, Stars(vs))) => Stars(inj(r, c, v1)::vs)

   178   case (OPTIONAL(r), v) => Stars(inj(r, c, v)::Nil)

   179   case (NTIMES(r, n), Sequ(v1, Stars(vs))) => Stars(inj(r, c, v1)::vs)

   180 }

   181 \end{lstlisting}

   182 \end{textblock}

   183 

   184 

   185 \begin{textblock}{5}(3,13.5)

   186 \bl{$r^? \dn r^{\{0..1\}}$}

   187 \end{textblock}

   188 

   189 \end{frame}

   190 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   

   191