--- a/handouts/ho04.tex	Tue Sep 26 14:07:29 2017 +0100
+++ b/handouts/ho04.tex	Tue Sep 26 14:08:49 2017 +0100
@@ -91,11 +91,13 @@
 letters, while values just start with a single upper-case
 character and the rest are lower-case letters.
  
-{\small\lstinputlisting[language=Scala,numbers=none]
+{\small\lstinputlisting[language=Scala,numbers=none,linebackgroundcolor=
+                  {\ifodd\value{lstnumber}\color{capri!3}\fi}]
 {../progs/app01.scala}}
 
  
-{\small\lstinputlisting[language=Scala,numbers=none]
+{\small\lstinputlisting[language=Scala,numbers=none,linebackgroundcolor=
+                  {\ifodd\value{lstnumber}\color{capri!3}\fi}]
 {../progs/app02.scala}}
 
 
@@ -580,7 +582,9 @@
 \end{figure}
 
 \begin{figure}[p]
-\lstinputlisting{../progs/app61.scala}
+\small  
+\lstinputlisting[numbers=left,linebackgroundcolor=
+   {\ifodd\value{lstnumber}\color{capri!3}\fi}]{../progs/app61.scala}
 
 \caption{The Scala code for the simplification function. The
 first part defines some auxillary functions for the rectification.
@@ -639,7 +643,8 @@
 be regarded as a regular expression. The extended definition
 in Scala therefore looks as follows:
 
-{\small\lstinputlisting[language=Scala]
+{\small\lstinputlisting[language=Scala, numbers=none,linebackgroundcolor=
+                  {\ifodd\value{lstnumber}\color{capri!3}\fi}]
 {../progs/app03.scala}}
 
 \noindent Since we regard records as regular expressions we
@@ -648,7 +653,8 @@
 to extend the definition of values, which in Scala looks as
 follows:
 
-{\small\lstinputlisting[language=Scala]
+{\small\lstinputlisting[language=Scala, numbers=none,linebackgroundcolor=
+                  {\ifodd\value{lstnumber}\color{capri!3}\fi}]
 {../progs/app04.scala}}
 
 \noindent Let us now look at the purpose of records more