Re: Perl, etc has these "?"-prefix modifiers/codes/whatever. Precisely which does emacs have (and NOT have)?

[John Withers]

On Thu, 2010-02-18 at 20:02 +0100, Pascal J. Bourguignon wrote:
<snip>
> 
> In the case of "regular expressions", when you add certain extensions,
> they're not regular expressions at all, so, I will just cite Jamie
> Zawinski:
<snip quote we all know here>

While in the strict sense you are obviously correct, that really doesn't
matter when you are programmer using a feature of your text editor. In
practice we aren't using them to strictly define regular languages in
some kind of formal language theory bakeoff. Well, I don't know that for
a fact. You seem like a pretty smart guy and that might be your hobby.
But in general, we are using them to get crap done.

It doesn't matter to me if for reasons of formal definition we rename a
modern regular expression engine as a MooCowPerlCrap engine in order not
to conflict with the formal definition. I still will argue that having a
MCPC engine would be a nice feature. Heck, emacs has a rich history of
using terms that no one in the wider, growing world gets as time goes on
anyway (I am talking to you, frames).

sed, grep, xemacs and pretty much the entire rest of the ecosystem
caught this idea quite some time ago, and it would be nice to have these
features in emacs. 

The quote you are pulling is from a discussion of exactly this issue, as
I am sure you are aware. But the funny thing here is that Jamie in the
last few years was using Perl extensively. He might not like it, but he
was using it:
http://regex.info/blog/2006-09-15/247#comment-3085

I don't disagree that regexes might be a pain or overused, but what I
don't get is the idea that if you are going to have them in the first
place, you don't add some pretty handy features that the rest of the
ecosystem has been using for decades now and won't degrade the base
features, if for some reason of formal purity you decide to use only
those.

I dunno, then again, I might just not be getting the emacs way. I have
only been using emacs a few years and my lisp skills aren't that strong,
and except for org-mode I use my emacs almost always in its tertiary
role as a programmers text editor.

john withers