Thanks for posting your filters. I guess what I mean is that apparently in real-life backtracking and related features aren't required. In fact, I find them a source of distraction and bugs in my regexes. For instance, if you want to parse C source code, you might say something like:
/((?:const\s+)*)\s+(\w+)\s+(\w+);/
Now suppose the C code has a bug, and it defines a variable like this:
const int;

Then your three regex captures look like:
$1==''
$2=='const'
$3==int

which clearly wasn't the intended result.

This happens because of backtracking for instance.

If you look at regex history, people had NFA/DFA machines from computer science theory, and they said a "language" is whatever passes through these machines. So that's what regexes matched. Nowadays, Perl has actually introduced things like non-backtracking constructs, namely '(?>'; essentially, acknowledging the "problem". However, I'm not quite sure why non-backtracking shouldn't be all you need in a "real-life" situation.

Thanks a lot for everyone's comments.

Reza.

In reply to Re^2: Perl regex in real life by RezaRob
in thread Perl regex in real life by RezaRob

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