2013/8/4 Richard Wordingham <[email protected]> > Also missing are precomposed forms for the likes of <OMICRON, > COMBINING DOUBLE BREVE, UPSILON>, described as a final diphthong > shortened before a following vowel. > They are not missing, they are encoded just the way you write it. They are not needed in fact, but they just should be documented somewhere for implementers of renderers and fonts, to support these types of clusters.
May be it will be enough to include them somewhere in CLDR data (notably if they are still not listed explicitly in the Greek collation table), or in an informative technical report for the Greek script, enumerating more completely the clusters that should be supported and listing some known practices and recommanded encodings (possibly with exceptions for some usages discussed in the report). I suggest an informative technical report instead of extending The Unicode standard itself, only because it will not be normative, and will be subject to updates. And the same could be developed for other scripts as well (notably for Semitic and Indic scripts). The Latin script would probably need several separate reports for different usages (notably, one for orthographic usages in modern languages, another for specialized epigraphic, old orthographies, and a specific section for use and styling of the Latin script within East-Asian scripts, and another for phonetic, phonologic, notations; the mathematical and technical formula notations using LAtin letters should be referencing appropriate documents for this usage). Each report for each script should also document their usage of "common" or "inherited" characters. Some of these usages are described in standardized properties, formalized in TUS). These evolving informative reports would become bases for discussions for improving later these properties (and related algorithms).
