Thanks all! Kevin, I think you make a really good point that the lookbehind isn't necessary. If I'm checking for the termination of /[0-9]+$ that is sufficient to know that the string ends with that pattern.
On Tue, May 27, 2025 at 3:24 PM Kevin Ushey <kevinus...@gmail.com> wrote: > Hi Josiah, > > Why not share a reprex / something we can copy and paste to directly > reproduce the issue? > > In any case, I suspect this depends on the underlying PCRE > implementation, and so isn't really directly an R issue. You might > have luck if you rewrite your regular expression from: > > (?<=(FeatureServer|MapServer)/)[0-9]+/?$ > > to something like (I didn't count parentheses below so assume I made a > mistake) > > (?:(?<=FeatureServer)|(?<=MapServer)))/)[0-9]+/?$ > > Or, alternatively -- does this really need to be a lookbehind? Can you > just match that text as-is and then capture whatever you happen to > find in front of it? > > Best, > Kevin > > On Tue, May 27, 2025 at 3:07 PM Josiah Parry <josiah.pa...@gmail.com> > wrote: > > > > Hi all, > > > > I've encountered an issue where using `perl = TRUE` for regular > expressions > > with grepl() causes an error on ubuntu CI runners only. > > > > Is this a known limitation of perl = TRUE for grep and family in base R? > Or > > is there a suggested workaround? > > > > The issue is specifically with lookbehinds: > > > > PCRE pattern compilation error > > 'lookbehind assertion is not fixed length' > > at '(?<=(FeatureServer|MapServer)/)[0-9]+/?$' > > > > Any guidance would be very much appreciated! I'd like to avoid adding a > > stringi dependency if possible. > > > > [[alternative HTML version deleted]] > > > > ______________________________________________ > > R-package-devel@r-project.org mailing list > > https://stat.ethz.ch/mailman/listinfo/r-package-devel > [[alternative HTML version deleted]] ______________________________________________ R-package-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-package-devel
