--On Tuesday, June 13, 2017 17:02 -0600 Peter Saint-Andre <stpeter@xxxxxxxxxx> wrote: > Hi Matt, thanks for the review - it's much appreciated. > > Just so you know: through discussion of Daniel Migualt's > secdir review of 7700bis (we're progressing them all together > this time!), I realized that it might be help to add another > example of visually confusing characters to 7564bis, so I plan > to mention CYRILLIC SMALL LETTER A U+0430 vs. LATIN SMALL > LETTER A U+0061 (which will be more familiar to readers than > the Cherokee characters already in the document). Peter, I don't want to throw the proverbial spanner in the works, but, just as things changes just as the original PRECIS documents were being published, I wonder if some other things that appear to be in process now could do it to us again. For example, consider draft-freytag-troublesome-characters. Despite having contributed to it and expecting to continue to do so, I've got some misgivings about the document and proposed registry as IETF work but, if it were to be adopted, it seems to me that it would be useful for the PRECIS documents to normatively reference it, especially for Identifier Class. To some extent, that draft is a remedy for some of the issues raised in the long-stalled draft-klensin-idna-5892upd-unicode70, but it doesn't make those issues, and the lack of comprehensiveness of normalization, go away. Probably less important, but it might be advantageous to incorporate some of the "whatever decisions you make, people will probably hold you accountable if there are problems" tone of draft-klensin-idna-rfc5891bis into the PRECIS documents. It might even be that RFC 7940, possibly supplemented by draft-freytag-lager-variant-rules, would be a better, or at least useful alternative, way to present some or all of the PEECIS rule sets than the current approach. On a somewhat different topic, the Greek, Latin, and Cyrillic scripts are so closely related that finding examples of pairs of similar-looking characters is in the low-lying fruit category because the similarities are not coincidences but the result of derivation and extensive borrowing (something of the same thing can be said for the Latin-Cherokee relationship, at least in printed, rather than cureive, forms). The examples that may be more scary, just because there is no evolutionary theory to predict were to look, would be things like the resemblances among the Latin U+006F, the Lao U+0ED0, the Ethiopic U+12D0, the New Tai Lue U+19D0, and of course the ASCII/European digit U+0030 and probably many more, with the group perhaps best described as "open circle graphemes" or something like that. best, john