On Friday, 21 September 2018 at 12:15:52 UTC, NX wrote:
How can I properly convert a character, say, first one to upper case in a unicode correct manner?
That would depend on how you'd define correctness. If your application needs to support "all" languages, then (depending how you interpret it) the task may not be meaningful, as some languages don't have the notion of "upper-case" or even "character" (as an individual glyph). Some languages do have those notions, but they serve a specific purpose that doesn't align with the one in English (e.g. Lojban).
In which code level I should be working on? Grapheme? Or maybe code point is sufficient?
Using graphemes is necessary if you need to support e.g. combining marks (e.g. ̏◌ + S = ̏S).
