On Thu, 14 Mar 2013 14:49:18 -0700 Markus Scherer <[email protected]> wrote:
> However, it does not make a lot of sense to set the variable top to > something above the currency symbols range -- it's basically an > option for an "ignore punctuation" mode, and you wouldn't want to > ignore nearly every assigned character in Unicode. There are a lot of characters in the SIP! While variableTop="u2FD5" would probably be a mistake or a mischievous experiment, some might be tempted to blot out all non-Han characters! I don't think there is a real problem yet, but it is an annoying fact that there can be a difference depending on whether one uses 16- or 32-bit weights. The good news is that there is a solution, namely to introduce fractional weights to the allkeys format under the headings of 'large weights' and 'escape hatch'. The issue first occurred to me when I realised a minor threat to the large weight scheme, for which there's a notional 50,000-character example in UTS#10. This is the rising number of variable codepoints (stretching terminology) encoded in Unicode. The highest variable weight in DUCET has risen even faster than the number of variable codepoints. The implicit weights steer well clear of this problem by only taking blocks of 32,768 characters for each initial primary weight. > However, we have agreed to replace the > hard-to-use variableTop attribute with an easy-to-use maxVariable > attribute, so this whole discussion will become moot at that point: > http://unicode.org/cldr/trac/ticket/5016 Actually, you've only proposed deprecating it. Richard.
