In reference to this discussion:
I solved almost all the problems, but one thing still remains obscure to me.
The difficulty is twofold, since it involves on the one hand creating the correct lookups for the font, on the other hand making sure that the text code applies them in turn correctly.
Now, (Lua)LaTeX with Fontspec and Babel allows you to choose among several options: 1) monotonic modern Greek, 2) polytonic modern Greek, 3) ancient greek (polytonic). In this case the code I use is the following:
\usepackage[italian]{babel}
\babelprovide[import]{ancientgreek}
\babelprovide[import]{polytonicgreek}
\babelprovide[import]{greek}But I should set up appropriate scripts in the font. Now, also by consulting for example this list:
https://docs.microsoft.com/en-us/typography/opentype/spec/languagetags
https://docs.microsoft.com/en-us/typography/opentype/spec/languagetags
I can't find specific tags related to ancient Greek.
I tried using the GRC and GRK specifications (in addition to PGR), which however do not seem to be correct otf tags.
I tried using the GRC and GRK specifications (in addition to PGR), which however do not seem to be correct otf tags.
In fact, a verification of the font tells me:
otfinfo -s SimonciniGaramondPro.otf DFLT Default grek Greek grek.GRC Greek / <unknown language> <======= grek.GRK Greek / <unknown language> <======= grek.PGR Greek / Polytonic Greek latn Latin latn.AZE Latin / Azeri latn.CRT Latin / Crimean Tatar latn.DEU Latin / German latn.FRA Latin / French latn.ITA Latin / Italian latn.MOL Latin / Moldavian latn.ROM Latin / Romanian latn.TRK Latin / Turkish.
Now, is there any way out? Can't 'locl' lookups have Greek as their language and 'ancient' as specification?
What are the linguistic alternatives allowed?