> On 6 Jun 2016, at 18:04, Ken Whistler <kenwhist...@att.net> wrote: > > UAX #44 doesn't *require* any regex engine to include this "is prefix" > handling.
Are you referring to the fact that the first paragraph on http://unicode.org/reports/tr44/#Matching_Rules uses “strongly recommended” and “should” instead of “required” and “must”? > What UAX #44 does is recommend that all property and property value aliases > be correctly recognized, and then specifies a clear statement (in UAX44-LM3) > of the loose matching rule for recognizing the various forms of those aliases > that could be considered equivalent. I don't think messing with that rule > statement (which has been in place since 2010) would be helpful. Why not? What I had in mind was adding a small sentence like: > For compatibility reasons, implementations may optionally support any initial > prefix string "is". This wouldn’t be a breaking change in any way, and it would enable new implementations that aim to follow UAX44 to do so without having to support `is`, and it would solve the problem everywhere the matching rules get applied rather than just for regular expressions. > I think the target of concern here is wrong. Not sure I agree. It seems to me the `is` prefix is problematic (for the same reasons) wherever it’s used, whether that’s in regular expressions or not. > The target instead should be in UTS #18, which happily, has a proposed update > available for comment right now: > > http://www.unicode.org/review/pri325/ > > The relevant point is: > > http://www.unicode.org/reports/tr18/tr18-18.html#RL1.2 > > That is the conformance part that requires that conformant Unicode regex > implementations "must follow the Matching rules from [UAX44]". Thanks for the pointer! I will submit my feedback there as well. It seems more awkward / difficult to add an exception there rather than just slightly tweaking the UAX44-LM3 text as suggested above, though.
