
diff -r 3be23d0df3db -r 33cff35bdc1a cws/cw03.tex
--- a/cws/cw03.tex	Thu Dec 01 13:07:32 2022 +0000
+++ b/cws/cw03.tex	Fri Dec 02 16:26:20 2022 +0000
@@ -58,15 +58,16 @@
 coursework. For this you might want to filter out whitespaces and
 comments. Your parser should be able to handle the WHILE programs in
 Figures~\ref{fib} -- \ref{collatz}.  In addition give the
-parse tree for the statement:
+parse tree according to your grammar for the statement:
 
 \begin{lstlisting}[language=While,numbers=none]
 if (a < b) then skip else a := a * b + 1
 \end{lstlisting}
 
 \noindent
-A (possibly incomplete) datatype for parse trees in Scala is shown
-in Figure~\ref{trees}.
+The output of the parser is an abstract syntax tree (AST).
+A (possibly incomplete) datatype for ASTs of the WHILE language
+is shown in Figure~\ref{trees}.
 
 \begin{figure}[p]
 \begin{lstlisting}[language=Scala]
@@ -95,14 +96,14 @@
 case class Lop(o: String, b1: BExp, b2: BExp) extends BExp
                      // logical operations: and, or
 \end{lstlisting}
-\caption{The datatype for parse trees in Scala.\label{trees}}
+\caption{The datatype for abstract syntax trees in Scala.\label{trees}}
 \end{figure}
 
 \subsection*{Question 3}
 
 Implement an interpreter for the WHILE language you designed
 and parsed in Question 1 and 2. This interpreter should take
-as input a parse tree. However be careful because, programs
+as input an AST. However be careful because, programs
 contain variables and variable assignments. This means
 you need to maintain a kind of memory, or environment,
 where you can look up a value of a variable and also




