Date: Sun, 16 Apr 2017 18:37:32 -0500 From: Kyle Evans <kevans91@ksu.edu> To: <freebsd-hackers@freebsd.org> Subject: Re: Replacing libgnuregex Message-ID: <CACNAnaEzEzw9Dtq0XO9W-U0ytyW-6Gvmc-DKJhjMeeRMePhAsg@mail.gmail.com> In-Reply-To: <20170416204326.GA24950@britannica.bec.de> References: <CACNAnaEmBjWudEJwvRTSqyciOp7-oRbCEQ_e6qtGsap0oHQ4yw@mail.gmail.com> <20170416134756.GA88424@stack.nl> <20170416204326.GA24950@britannica.bec.de>
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On Sun, Apr 16, 2017 at 3:43 PM, Joerg Sonnenberger <joerg@bec.de> wrote: > On Sun, Apr 16, 2017 at 03:47:56PM +0200, Jilles Tjoelker wrote: > > On Tue, Apr 11, 2017 at 03:20:58PM -0500, Kyle Evans wrote: > > > On the other hand, I think I could fairly easily implement most of > these > > > into libc/regex. Here's a summary of what this option entails adding to > > > libc/regex, from what I've found: > > > > > [snip] > > > * Add backreferences (\1 through \9) to EREs > > > [snip] > > > > Adding this enforces that EREs, like BREs, may sometimes require > > exponential time to match. I would prefer to avoid that. > > The Spencer RE doesn't need backreferences to be exponential, but I > certainly agree that adding support for them makes it more difficult to > change to a better RE implementation later. > Are there plans in progress to replace this at some point? If not, would it be acceptable to lib'ify what we have now, ensure the libc bits remain strict POSIX (-DPOSIX_STRICT to exclude any GNU cruft, not just disabled at runtime), and have the libregex version include GNU extensions? This seems likes a reasonable approach to make sure expectations of libc remain as they are now while also not introducing more maintenance overhead, assuming there are no immediate plans to replace the regex implementation.
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