I had heard that perl regular expressions are already Turing complete. Never verified it, though. E.g. http://books.slashdot.org/comments.pl?sid=143298&cid=1

I had heard that perl regular expressions are already Turing complete. Never verified it, though. E.g. http://books.slashdot.org/comments.pl?sid=143298&cid=12015194 http://books.slashdot.org/comments.pl?sid=143298&cid=120...