On 26 Mar 2017, at 16:45, Asmus Freytag <asm...@ix.netcom.com> wrote: > > The priority in encoding has to be with allowing distinctions in modern > texts, or distinctions that matter to modern users of historic writing > systems. Beyond that, theoretical analysis of typographical evolution can > give some interesting insight, but I would be in the camp that does not > accord them a status as primary rationale for encoding decisions.
Our rationales are NOT ranked in the way you suggest. A variety of criteria are applied. > Thus, critical need for contrasting use of the glyph distinctions would have > to be established before it makes sense to discuss this further. Precedent for such needs is well-established. Consider the Latin Extended-D block. Sometimes it is editorial preference, and that’s not even always universal. > I see no principled objection to having a font choice result in a noticeable > or structural glyph variation for only a few elements of an alphabet. We have > handle-a vs. bowl-a as well as hook-g vs. loop-g in Latin, and fonts > routinely select one or the other. Well, Asmus, we encode a and ɑ as well as g and ɡ and ᵹ. And we do not consider ɑ and ɡ and ᵹ to be things that ought to be distinguished by variation selectors. (I am of course well aware of IPA usage.) Whole-font switching is well understood. But character origin has always been taken into account. Consider 2EBC ⺼ CJK RADICAL MEAT and 2E9D ⺝ CJK RADICAL MOON which are apparently really supposed to have identical glyphs, though we use an old-fashioned style in the charts for the former. (Yes, I am of course aware that there are other reasons for distinguishing these, but as far as glyphs go, even our standard distinguishes them artificially.) > (It is only for usage outside normal text that the distinction between these > forms matters). What’s “normal” text? “Normal” text in Latin probably doesn’t use the characters from the Latin Extended-D block. > While the Deseret forms are motivated by their pronunciation, I'm not > necessarily convinced that the distinction has any practical significance > that is in any way different than similar differences in derivation (e.g. for > long s-s or long-s-z for German esszett). One practical consequence of changing the chart glyphs now, for instance, would be that it would invalidate every existing Deseret font. Adding new characters would not. > In fact, it would seem that if a Deseret text was encoded in one of the two > systems, changing to a different font would have the attractive property of > preserving the content of the text (while not preserving the appearance). Changing to a different font in order to change one or two glyphs is a mechanism that we have actually rejected many times in the past. We have encoded variant and alternate characters for many scripts. > This, in a nutshell, is the criterion for making something a font difference > vs. an encoding distinction. Character identity is not defined by any single criterion. Moreover, in Deseret, it is not the case that all texts which contain the diphthong /juː/ or /ɔɪ/ write it using EW 𐐧 or OI 𐐦. Many write them as Y + U 𐐏𐐋 and O + I 𐐄𐐆. So the choice is one of *spelling*, and spelling has always been a primary criterion for such decisions. >> This is complicated by combining characters mostly identified by glyph, and >> the fact that while ä and aͤ may be the same character across time, there >> are people wanting to distinguish them in the same text today, and in both >> cases the theoretical falls to the practical. In this case, >> there are no combining character issues and there's nobody needing to use >> the two forms in the same text. > > huh? He’s wrong there, as I pointed out. A text in German may write an older Clavieruͤbung in a citation alongside the normal spelling Klavierübung. The choice of spelling is key. Michael Everson
