I don't have an answer, mostly because I know nothing about Hangul. Maybe decomposition is the right solution there. Frankly I don't care what Unicode does to solve the problems Hangul creates, and as Korea about 1% of the world's population I doubt many other people here care either.
I'm commenting about Latin languages. There is absolutely no doubt what is easiest for a programmer there: one code point per grapheme. We've tried considering 'A' and 'a' the same in both computer languages and file systems. It was a mess. No one does it any more.
> But then you get other problems, such as that you can't decompose them so you can cleverly match 'á' when you search for 'a'
It's not a problem. We know how to match 'A' and 'a', which are in every sense closer than 'á' and 'a' ('á' and 'a' can be different phonetically, 'A' and 'a' aren't). If matching both 'A' and 'a' isn't a major issue, why would 'á' and 'a' be an issue that Unicode must to solve for us?
In fact given it's history I'm sort of surprised Unicode didn't try and solve it by adding a composition to change case. shudder
> And we haven't even gotten to case issues.
The "case issues" should not have been Unicode's issue at all. Unicode should have done one thing, well. That one thing was ensure visually distinct string had one, and only one, unique encoding.
There is objective reason for wanting that. Typically programmers do not do much with strings. The two most common things they do is move them around, and compare them for equality but also sort them. They naturally don't read the Unicode standard. They just expect the binary representation of strings to faithfully follow what their eyes tell them should happen: if two strings look identical, their Unicode representation will be identical. It's not an unreasonable expectation. If it's true those basic operations of moving and comparing will be simple, and more importantly efficient on a computer.
The one other thing we have to do a lot less often, but nonetheless occupies a fair bit of our time is parsing a string. It occupies our time because it's fiddly and takes a lot of code, and is error prone. I still remember the days when languages string handling are a selection criteria. (It's still the reason I dislike Fortran.) I'm not talking about complex parsing here - it's usually something like spilt it into words or file system path components, or going looking for a particular token. It invariably means moving along the string one grapheme at time, sniffing for what you want and extracting it. (Again this quite possibly is only meaningful for Latin based languages - but that's OK because the things we are after are invariably Latin characters in configuration files, file names and the like. The rest can be treated as uninteresting blobs.) And now Unicode's composition has retrospectively simple operation far harder to do correctly.
All other text handling programmers do is now delegated to libraries of some sort. You mention one: nobody does case conversion themselves. They call strtolower() for ASCII or a Unicode equivalent. Hell, as soon as you leave Latin we even printing it correctly requires years of expertise to master. The problems that crop up may as you say may be unavoidable, but that's OK because they are so uncommon I'm willing to wear the speed penalty to use somebody else's code to do it.
> it did not happen because of "egos" on the Unicode Consortium, or because of "national egos", or politics, or anything.
Did someone say that? Anyway, it's pretty obvious why it happened. When a person invents new hammer, the second thing they do is going looking for all the other problems it might solve. A little tweak here and it would do that job too! I saw an apprentice sharpen the handle of his Estwing hammer once. It did make it a useful wire cutter in a pinch, but no prizes for guessing what happen when he just using it as a hammer.
Unicode acquired it's warts by attempting to solve everybody's problems. Instead of making it more and more complex, they should have ruthlessly optimised it to make it work near flawlessly it's most common user: a programmer who couldn't give a shit about internationalisation, and wasted the bare minimum of his time on stackoverflow before using it.
The tragedy is it didn't do that.
> Did someone say that?
Yes, u/kazinator did.
> Anyway, it's pretty obvious why it happened. When a person invents new hammer, the second thing they do is going looking for all the other problems it might solve.
That's not why decomposition happened. It happened because a) decomposition already existed outside Unicode, b) it's useful. Ditto pre-composition.
> Unicode acquired it's warts by attempting to solve everybody's problems.
Unicode acquired its warts by attempting to be an incremental upgrade to other codesets. And also by attempting to support disparate scripts with disparate needs. The latter more than the former.
> Instead of making it more and more complex, they should have ruthlessly optimised it to make it work near flawlessly it's most common user: a programmer who couldn't give a shit about internationalisation, ...
They did try to ruthlessly optimize it: by pursuing CJK unification. That failed due to external politics.
As to the idea that programmers who want nothing to do with I18N are the most common user or Unicode, that's rather insulting to the real users: the end users. All of this is to make life easier on end users: so they need not risk errors due to not their (or their SW) not being able to keep track of what codeset/encoding some document is written in, so they can mix scripts in documents, and so on.
Unicode is not there to make your life harder. It's there to make end users' lives easier. And it's succeeded wildly at that.
> > And we haven't even gotten to case issues.
> The "case issues" should not have been Unicode's issue at all. Unicode should have done one thing, well. That one thing was ensure visually distinct string had one, and only one, unique encoding.
You really should educate yourself on I18N.
Oh for Pete's sake. Unicode / ASCII / ISO 8859-1 are encoding computers and thus programmers use to represent text. Users don't read Unicode, they read text. They never, ever have to deal with Unicode and most wouldn't know what it was if it leapt up and hit them in the faxe, so if Unicode justified adding features to accommodate these non-existent users, I guess that explains how we got into this mess.
Whether you like it or not, Unicode exists to make USERS' lives better. Programmers?? Pfft. We can deal with the complexity of all of that. User needs, on the other hand, simply cannot be met reasonably with any alternatives to Unicode.
They've been using multiple scripts long before computers. When computers came along those users quite reasonably demanded they be able to write the same scripts. This created a problem for the programmers. The obvious solution is a universal set of code points - and ISO 10646 was born. It was not rocket science. But if it had not come along some other hack / kludge would have been used because the market is too large to be abandoned by the computer companies. They would have put us programmers in a special kind of hell, but I can guarantee the users would not have known about that, let alone cared.
Oddly the encoding schemes proposed by ISO 10646 universally sucked. Unicode walked into that vacuum with their first cock up - 16 bits was enough for anybody. It was not just dumb because it was wrong - it was dumb because they didn't propose unique encoding. They gave us BOM markers instead. Double fail. They didn't win because the one thing they added, their UCS-2 encoding, was any better than what came before. They somehow managed to turn it into a Europe vs USA popularity contest. Nicely played.
Then Unicode and 10646 became the same thing. They jointly continued on in the same manner as before, inventing new encodings to paper over the UCS-2 mistake. Those new encodings all universally sucked. The encoding we programmers use today, UTF-8, was invented by, surprise, surprise, a programmer who was outside of Unicode / 10646 group think. It was popularised at a programmers conference, USENIX, and from there on it was obvious was going to be used regardless of what Unicode / 10646 thought of it, so they accepted it.
If Perl6 is any indication, the programmers are getting the shits with the current mess. Perl6 has explicitly added functions that treat text as a stream of grapheme's rather than Unicode code points. The two are the same of course except when your god damned compositions rear their ugly head - all they do is eliminate that mess. Maybe you should take note. Some programmers have already started using something other than Unicode because it makes their jobs easier. If it catches on you are going to find out real quickly just how much the users care about the encoding scheme computers use for text.
None of this is to trivialise the task of assigning code points to grapheme's. It's huge task. But for pete's sake don't over inflate your ego's by claiming you are doing some great service for mankind. The only thing on the planet that uses the numbers Unicode assigns to characters as is computers. Computers are programmed by one profession - programmers. Your entire output is consumed by that one profession. Yet for all the world what you've written here seems to say Unicode has some higher purpose, and you are optimising for that, whatever it may be. For gods same come down to earth.
Please also not that all string handling in Raku (the `Str` class) is based on graphemes, not just some added functions. This e.g. means that a newline is always 1 grapheme (regardless of whether it was a CR or LF or CRLF). And that for é there is no difference between é (LATIN SMALL LETTER E WITH ACUTE aka 0x00E9) and (LATIN SMALL LETTER E, COMBINING ACUTE ACCENT aka 0x0065, 0x0301).
Please note that for any combination between characters and combiners for which there does not exist a composed version in Unicode, Raku will create synthetic codepoints on the fly. This ensures that you can consider your texts as graphemes, but still be able to roundtrip strange combinations.