UAX44: loose matching of symbolic values and the `is` prefix

Doug Ewell doug at
Tue Jun 7 14:51:57 CDT 2016

Mathias Bynens wrote:

>> Rather than changing the spec based on anecdotal evidence, [...]
>> It seems irresponsible to assume now that nobody anywhere needs
>> it.
> What assumption are you talking about? Markus and Nova provided actual
> examples of implementations not following the spec, and so far no one
> has been able to provide even a single counter-example.

I read the synopsis of Nova's IUC38 presentation, and it looks like he
did some pretty thorough research into regex engines, so I take back the
phrase "based on anecdotal evidence."

Changes to a Unicode specification that would have the effect of
removing functionality normally trigger a public review. They help tease
out the edge cases better than a mailing list discussion. The UTC has
done well to make frequent use of this mechanism when potentially
breaking changes are being considered.

>> There must have been some basis for including the "is" case in the
>> first place.
> Now *that* sounds like an assumption to me.

Do you suppose they just made it up out of whole cloth?

Doug Ewell | | Thornton, CO ����

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