added
authorChristian Urban <christian dot urban at kcl dot ac dot uk>
Sat, 23 Nov 2013 11:09:27 +0000
changeset 202 180cbfc1520a
parent 201 c813506e0ee8
child 203 f1335c171d50
added
coursework/cw03.pdf
coursework/cw03.tex
Binary file coursework/cw03.pdf has changed
--- a/coursework/cw03.tex	Sat Nov 23 09:17:59 2013 +0000
+++ b/coursework/cw03.tex	Sat Nov 23 11:09:27 2013 +0000
@@ -97,7 +97,7 @@
 in a txt-file or as pdf.\bigskip
 
 
-\subsection*{Question 1 (marked with 1\%)}
+\subsection*{Question 1 (marked with 2\%)}
 
 You need to lex and parse WHILE programs and submit the assembler 
 instructions for the Fibonacci program and for the program you submitted
@@ -113,6 +113,32 @@
 \texttt{for} \;\textit{Id} \texttt{:=} \textit{AExp}\; \texttt{upto} \;\textit{AExp}\; \texttt{do} \textit{Block} 
 \end{center}
 
+\noindent
+The intended meaning is to first assign the variable \textit{Id} the value of the first arithmetic 
+expression, then go through the loop, at the end increase the value of the variable by 1, 
+and finally test wether the value is not less or equal anymore to the value of the second
+arithmetic expression. For example the following instance of a \texttt{for}-loop 
+is supposed to print out the numbers \texttt{2}, \texttt{3}, \texttt{4}.
+
+
+\begin{center}
+\begin{minipage}{6cm}
+\begin{lstlisting}[language=While,basicstyle=\ttfamily, numbers=none]
+for i := 2 upto 4 do {
+    write i	
+}
+\end{lstlisting}
+\end{minipage}
+\end{center}
+
+\noindent
+There are two ways how this can be implemented: one is to adapt the code generation 
+part of the compiler and generate specific code for \texttt{for}-loops; the other is to
+translate the abstract syntax tree of \texttt{for}-loops into an abstract syntax tree using
+existing language constructs (for example while loops).
+
+
+
 \end{document}
 
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