> No. What you have demonstrated below is that given an API > based on characters, one can write an API based on > default grapheme clusters. Nonetheless, it is only the > resulting default-grapheme-cluster-based API which would > actually be of any use to end-users.
How close to the "end" do users have to be before we start worrying about what they need? Every hacker is also a user. > I have yet to see an APPLICATION which needs a character- > based API. XSLT, XPointer, XPath... Okay, they're all applications of XML but they operate at a level in which they are required to be neutral to encodings, but also at which they are either below the stage at which issues about default and tailored grapheme clusters are dealt with (so any processing from characters to grapheme clusters may prove to be incorrect further down the line) or else where such matters are irrelevant (particularly common with 'data' rather than 'document' uses of XML - and these technologies act at a level lower than which allows that distinction to be made). Hence they necessarily operate on characters.
