On Thu, Mar 14, 2013 at 4:09 PM, Richard Wordingham < [email protected]> wrote:
> 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! Richard, we are talking about collation here, and "variable top" works by comparing primaries with a threshold. With "above the currency symbols range" I of course meant "above" in collation order. 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. Yes, but a) this is a rarely used option and b) depends on the implementation, and c) it makes no practical sense to make letters ignorable. 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'. > "Fractional weights" is nothing other than the "large weights" mechanism applied to byte-based weights of all levels. The UCA is already "fractional" for implicit primaries. > 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. > And pinning the variable-top value to the next following end of a reordering group, and no higher than the end of the primary-weight range for currency symbols. markus
