
diff -r a9911966c0df -r 43c0ed473720 coursework/cw02.tex
--- a/coursework/cw02.tex	Tue Nov 10 22:27:46 2015 +0000
+++ b/coursework/cw02.tex	Sun Nov 15 21:31:31 2015 +0000
@@ -93,20 +93,40 @@
 \end{center}
 
 \noindent
+Try to design regular expressions to be as small as possible.
 
 \subsection*{Question 2 (marked with 3\%)}
 
 Implement the Sulzmann \& Lu tokeniser from the lectures. For
 this you need to implement the functions $nullable$ and $der$
-(you can use your code from CW 1), as well as $mkeps$ and
+(you can use your code from CW~1), as well as $mkeps$ and
 $inj$. These functions need to be appropriately extended for
-the extended regular expressions from Q1. Also add the record
-regular expression from the lectures and implement a function,
-say \pcode{env}, that returns all assignments from a value
-(such that you can extract easily the tokens from a value). 
+the extended regular expressions from Q1. Write down the 
+clauses for
 
-The functions $mkeps$ and $inj$ return values. Calculate the
-value for your regular expressions from Q1 and the string
+\begin{center}
+\begin{tabular}{@ {}l@ {\hspace{2mm}}c@ {\hspace{2mm}}l@ {}}
+$mkeps([c_1 c_2 \ldots c_n])$  & $\dn$ & $?$\\
+$mkeps(r^+)$                   & $\dn$ & $?$\\
+$mkeps(r^?)$                   & $\dn$ & $?$\\
+$mkeps(r^{\{n\}})$             & $\dn$ & $?$\medskip\\
+$inj\, ([c_1 c_2 \ldots c_n])\,c\,\ldots$  & $\dn$ & $?$\\
+$inj\, (r^+)\,c\,\ldots$                   & $\dn$ & $?$\\
+$inj\, (r^?)\,c\,\ldots$                   & $\dn$ & $?$\\
+$inj\, (r^{\{n\}})\,c\,\ldots$             & $\dn$ & $?$\\
+\end{tabular}
+\end{center}
+
+\noindent where $inj$ takes three arguments: a regular
+expression, a character and a value. Also add the record
+regular expression from the lectures to your tokeniser and
+implement a function, say \pcode{env}, that returns all
+assignments from a value (such that you can extract easily the
+tokens from a value).\medskip 
+
+\noindent
+Fiannly give the tokens for your regular expressions from Q1 and the
+string
 
 \begin{center}
 \code{"read n;"}




