[xsl] Regular Expressions in XPath 2.0

["Rashmi Rubdi" <rashmi.sub@xxxxxxxxx>]

I guess XPath is not off-topic to this list, if it is then I'm sorry
about this post.

I have just started learning the 2.0 versions of XSLT and XPath and
recently learned that Regular Expressions were introduced in XPath 2.0
and were not in XPath1.0.

I would like understand a few things about the Regular Expressions in
XPath 2.0.

According to the slide here:
http://www.mulberrytech.com/papers/XPath-2-0-User-Grp-HTML/slide060.html
the regular expressions in XPath are taken from Perl.

I've studied Regular Expressions in school a long time ago, but I've
never learned Perl.

I have a few questions

1) Are regular expressions in XPath 2.0 identical or are they similar
to those in Perl?

2) What would be the best approach to re-learn Regular Expressions
with respect to XPath 2.0, I know I have to first re-learn the basics
of regular expressions too.

I think there's a standard for Regular Expressions and each
programming language specializes or deviates from the standard.

Thank you for your input.

-Rashmi