
diff -r 3c040f4a7415 -r 2509c670e3a2 handouts/ho01.tex
--- a/handouts/ho01.tex	Sun Aug 05 21:37:35 2018 +0100
+++ b/handouts/ho01.tex	Sun Aug 05 21:52:40 2018 +0100
@@ -181,7 +181,8 @@
 \texttt{.r} converts a string into a regular expression. I
 leave it to you to ponder whether this regular expression
 really captures all possible web-addresses. If you need a quick
-recap about regular expressions, here is a quick video
+recap about regular expressions and how the match strings, 
+here is a quick video
 \url{https://youtu.be/bgBWp9EIlMM}.
 
 \subsection*{Why Study Regular Expressions?}
@@ -281,6 +282,13 @@
 \url{http://davidvgalbraith.com/how-i-fixed-atom/}
 \end{center}
 
+and when somebody tried to match web-addresses using regular
+expressions
+
+\begin{center}
+\url{https://www.tutorialdocs.com/article/regex-trap.html}
+\end{center}  
+
 \noindent
 Such troublesome regular expressions are sometimes called \emph{evil
   regular expressions} because they have the potential to make regular




