On Sun, 4 Oct 2015 14:29:16 -0700 "Asmus Freytag (t)" <asmus-...@ix.netcom.com> wrote:
> On 10/4/2015 12:38 PM, Richard Wordingham wrote: > The problem you are trying to solve is to allow editing on > the code point level, or, if you will, the keystroke level. > Generally, there will be a sweet spot for each language (and each > user) with respect to what to erase or undo. > For sequences that belong to a given language, you can pick the > behavior that makes most sense in them, but for lone surrogates, by > definition you are dealing with broken text that doesn't follow any > conventions. Who's 'you'? Customisation is frequently not available. In fact, I don't recall seeing it on offer. > It should also be something that doesn't occur commonly. So, for all > of those reasons, I see no particular problem with giving that a > "generic" behavior, which could be that of deleting the entire > combining sequence; especially if your interface normally deletes > sequences as a unit. > But in any case, the minimal requirement on an editor is that it lets > you delete (and then retype) enough text to get it back to an > uncorrupted state. In the problem I hit, I would nearly be left with two options - never having CANDRABINDU and always having it preceded by CANDRABINDU. Whenever I enter CANDRABINDU, it is preceded by the lone surrogate. Consequently, the option of retyping the sequence is of no avail. Fortunately, in the application where I met the problem, the lone surrogates, and nothing else, get deleted when the file is saved. The problem could very easily be a lot worse. ---- > Catch-22 here. In filtering input to the dialog to prevent it from > being used to corrupt text, you prevent it from being used to repair > text. Interesting. Not very different to having a very roll-stable aeroplane. If you ever do end up upside-down, you have a big problem. Richard.