[cl-ppcre-devel] Re: Weird :START Behaviour in CL-PPCRE:SCAN

[Chris Dean]

> By the way, what I'm trying to do is to parse string patterns like
> `[href]' and `[href text]'. And as you can realize from :START 13
> keyword, I'm previously determined that at 13th character, there
> exists a `['. Do you suggest any other method to parse such strings
> more efficiently?

A regex seems like a fine way to me.

> Next time, how can I understand when a regex will need that much
> backtracking? I'll be really appreciated if you'd explain the pattern
> a little bit more.

You can play around with the Regex Coach http://weitz.de/regex-coach/
and step through the matching.  If you really want a deeper
understanding Jeffrey Friedl's Mastering Regular Expressions is very
good.  And most compiler text books will cover regexs as well.

Maybe someone else has a simple backtracking explanation.

Cheers,
Chris Dean