--- a/msc-projects-12.html Tue Nov 06 00:04:58 2012 +0000
+++ b/msc-projects-12.html Tue Nov 06 20:19:35 2012 +0000
@@ -63,7 +63,7 @@
For example, if you use in <A HREF="http://www.python.org">Python</A> or
in <A HREF="http://www.ruby-lang.org/en/">Ruby</A> (probably also in other mainstream programming languages) the
innocently looking regular expression <code>a?{28}a{28}</code> and match it, say, against the string
- <code>aaaaaaaaaaaaaaaaaaaaaaaaaaaa</code>, you will soon notice that your CPU usage goes to 100%. In fact,
+ <code>aaaaaaaaaaaaaaaaaaaaaaaaaaaa</code> (that is 28 <code>a</code>s), you will soon notice that your CPU usage goes to 100%. In fact,
Python and Ruby need approximately 30 seconds for matching this string. You can try it for yourself:
<A HREF="http://www.dcs.kcl.ac.uk/staff/urbanc/cgi-bin/repos.cgi/afl-material/raw-file/tip/re.py">re.py</A> (Python version) and
<A HREF="http://www.dcs.kcl.ac.uk/staff/urbanc/cgi-bin/repos.cgi/afl-material/raw-file/tip/re-internal.rb">re.rb</A>