Re: [Patch] Support assertions and greedy/ungreedy matching in regex

[Tim Shen <timshen91 at gmail dot com>]

On Thu, Sep 12, 2013 at 9:57 AM, Paolo Carlini <paolo.carlini@oracle.com> wrote:
> Great. A quick-quick comment: if these are the last two features, why we
> can't un-xfail the testcase which we added latety? Also, a grep revealed a
> couple more xfails. Can you clarify?

I say `feature` when I think that, what these xfails reveal are too
small to be features, say, regex_search/regex_match flags. Now turns
out "feature" is not a good word for them. I do mean all C++ library
independent part, or pure regex function part, are done. Next days I
will add flags implementation.

> Also, much more generally, I would be curious about the remaining work: I
> think essentially it boils down to the vagaries for the other non-default
> regex dialects? Is it a lot of work?

This patch(http://gcc.gnu.org/ml/libstdc++/2013-08/msg00142.html)
already supports all dialects(ECMAScript, basic, extended, grep,
egrep, awk) specified by standard. Most of the differences between
them are eliminated by _Scanner, aka tokenizer, so it's actually not a
lot of work to even add one more syntax. But again, I think more
testcases are needed, especially from those experienced regex users.
I'm actually not a big fan of regex(but of NFA ;), or can I borrow
some boost/libc++ testcases without making any licence trouble?

Thanks!


-- 
Tim Shen