--- a/msc-projects-14.html Sun Nov 09 21:37:59 2014 +0000
+++ b/msc-projects-14.html Sun Nov 09 21:47:40 2014 +0000
@@ -49,14 +49,14 @@
<p>
<B>Description:</b>
<A HREF="http://en.wikipedia.org/wiki/Regular_expression">Regular expressions</A>
- are extremely useful for many text-processing tasks such as finding patterns in texts,
+ are extremely useful for many text-processing tasks, such as finding patterns in texts,
lexing programs, syntax highlighting and so on. Given that regular expressions were
introduced in 1950 by <A HREF="http://en.wikipedia.org/wiki/Stephen_Cole_Kleene">Stephen Kleene</A>,
you might think regular expressions have since been studied and implemented to death. But you would definitely be
mistaken: in fact they are still an active research area. For example
<A HREF="http://www.home.hs-karlsruhe.de/~suma0002/publications/regex-parsing-derivatives.pdf">this paper</A>
about regular expression matching and derivatives was presented just last summer at the international
- FLOPS'14 conference. The task in this project is to implement their results.</p>
+ FLOPS'14 conference. The task in this project is to implement their results and use them for lexing.</p>
<p>The background for this project is that some regular expressions are
“<A HREF="http://en.wikipedia.org/wiki/ReDoS#Examples">evil</A>”
@@ -106,9 +106,10 @@
(for example subexpression matching, which my rainy-afternoon matcher cannot). I am sure they thought
about the problem much longer than a single afternoon. The task
in this project is to find out how good they actually are by implementing the results from their paper.
- Their approach is based on the concept of derivatives.
- I used them once myself in a <A HREF="http://www.inf.kcl.ac.uk/staff/urbanc/Publications/rexp.pdf">paper</A>
- in order to prove the <A HREF="http://en.wikipedia.org/wiki/Myhill–Nerode_theorem">Myhill-Nerode theorem</A>.
+ Their approach to regular expression matching is also based on the concept of derivatives.
+ I used derivatives very successfully once for something completely different in a
+ <A HREF="http://www.inf.kcl.ac.uk/staff/urbanc/Publications/rexp.pdf">paper</A>
+ about the <A HREF="http://en.wikipedia.org/wiki/Myhill–Nerode_theorem">Myhill-Nerode theorem</A>.
So I know they are worth their money. Still, it would be interesting to actually compare their results
with my simple rainy-afternoon matcher and potentially “blow away” the regular expression matchers
in Python and Ruby (and possibly in Scala too). The application would be to implement a fast lexer for
@@ -623,7 +624,7 @@
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