So the point of this discussion was showing that HTML cannot be parsed, in general, using regular expressions and asserting "... it turns out that the programme

So the point of this discussion was showing that HTML cannot be parsed, in general, using regular expressions and asserting "... it turns out that the programmers who don't understand the pumping lemma are the same programmers who unnecessarily reinvent well established tools when faced with simple problems." I don't buy this. I've never heard of people attempting to develop a single regular expression to generally parse HTML/XML. The pumping lemma doesn't prevent people from using regular expressions to grab bits of info out of particular pages for which they know the layout. While there are maintainability and generality concerns with doing so, the "quick and dirty" regex approach can work in particular cases and isn't a sign that a developer lacks a proper grounding in FSM-theory... in fact, it might be a fine solution for one-off tasks.