# HG changeset patch
# User Christian Urban <christian.urban@kcl.ac.uk>
# Date 1698327020 -3600
# Node ID 5070392a1bd77e994deb250db8ecda9e9faf6470
# Parent  f5d2453c56406ae75d4768e1c78e8b003ea3a1d6
updated

diff -r f5d2453c5640 -r 5070392a1bd7 progs/lexer/lexer.sc
--- a/progs/lexer/lexer.sc	Wed Oct 25 13:54:11 2023 +0100
+++ b/progs/lexer/lexer.sc	Thu Oct 26 14:30:20 2023 +0100
@@ -59,9 +59,6 @@
 
 
 
-val r : Rexp = ("a" | "b").% 
-println(r) 
-
 def nullable(r: Rexp) : Boolean = r match {
   case ZERO => false
   case ONE => true
@@ -84,8 +81,6 @@
   case RECD(_, r1) => der(c, r1)
 }
 
-println(der('a', ALT(STAR("a"), "b")))
-
 // extracts a string from a value
 def flatten(v: Val) : String = v match {
   case Empty => ""
@@ -338,7 +333,8 @@
 //
 // which has been removed in Scala 3.
 //
-// for escaping strings in Scala 3
+// for escaping strings in Scala 3 use this equivalent code
+
 import scala.quoted._
 
 def escapeImpl(raw: Expr[String])(using Quotes): Expr[String] = {
diff -r f5d2453c5640 -r 5070392a1bd7 slides/slides03.pdf
Binary file slides/slides03.pdf has changed
diff -r f5d2453c5640 -r 5070392a1bd7 slides/slides05.pdf
Binary file slides/slides05.pdf has changed
diff -r f5d2453c5640 -r 5070392a1bd7 slides/slides05.tex
--- a/slides/slides05.tex	Wed Oct 25 13:54:11 2023 +0100
+++ b/slides/slides05.tex	Thu Oct 26 14:30:20 2023 +0100
@@ -80,7 +80,30 @@
 %  can stay unchanged. Use \texttt{ders} for CW2, not \texttt{ders2}!
 %  \end{frame}
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-    
+
+{
+\setbeamercolor{background canvas}{bg=cream}
+\begin{frame}<1-10>[c]
+\end{frame}
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\begin{frame}[c]
+  \frametitle{Coursework 1: Submissions}
+  
+  \begin{itemize}
+  \item Scala (162)
+  \item Ocaml (1)
+  \item Java (1)  \ldots uses new features of Java 21  
+  \item Rust (6)
+  \end{itemize}\bigskip\bigskip  
+  
+
+\end{frame}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+}
+
+
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \begin{frame}[t]
 \frametitle{Parser}
@@ -154,6 +177,36 @@
 \end{frame}
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
 
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+{
+\setbeamercolor{background canvas}{bg=cream}
+\begin{frame}[c]
+
+\begin{center}
+\begin{tikzpicture}[scale=1.5,>=stealth',very thick,
+                    every state/.style={minimum size=0pt,
+                    draw=blue!50,very thick,fill=blue!20}]
+  \node[state,initial]   (q0) at (0,2) {$q_0$};
+  \node[state,accepting] (q1) at (2,2) {$q_1$};
+  \node[state]           (q2) at (0,0) {$q_2$};
+  \node[state]           (q3) at (2,0) {$q_3$};
+
+  \path[->] (q0) edge[bend left] node[above] {\alert{$a$}} (q1)
+            (q1) edge[bend left] node[above] {\alert{$a$}} (q0)
+            (q2) edge[bend left] node[above] {\alert{$a$}} (q3)
+            (q3) edge[bend left] node[above] {\alert{$a$}} (q2)
+            (q0) edge[bend left] node[right] {\alert{$b$}} (q2)
+            (q2) edge[bend left] node[left]  {\alert{$b$}} (q0)
+            (q1) edge[bend left] node[right] {\alert{$b$}} (q3)
+            (q3) edge[bend left] node[left]  {\alert{$b$}} (q1);
+\end{tikzpicture}
+\end{center}
+
+\hfill{}Which language?
+
+\end{frame}
+}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -638,6 +691,24 @@
 \end{frame}
 
 
+\begin{frame}[t]
+\begin{minipage}{1.2\textwidth}  
+  \begin{mybox3}{}\small
+    \textbf{Questions regarding CFL CW1}
+
+Dear Dr Urban    
+    
+ Regarding CW1, I am stuck on finding the nullable and derivative rules for some important regexes.\smallskip
+
+The NOT Regex nullable rule: I am not sure how to approach this, I am inclined to simply put this as the negation of the nullable function on the input regex (e.g !nullable(r)). However I have found instances where negating a nullable does not make it un-nullable. For example the negation of r* can still match regex ab (which is not nullable). So I would like some actual clarification, pointers and help in this area.\smallskip
+
+The NOT Regex derivation rule: again I am dumbfounded here, I am inclined to think that I should derive the regex and then negate that derivation. But none of this ever works. Please provide some helpful information so I can solve this.
+\end{mybox3}
+\end{minipage}
+\end{frame}
+
+
+
 \end{document}
 
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