- From: Richard Wordingham <richard.wordingham@ntlworld.com>
- Date: Thu, 6 Aug 2015 08:52:12 +0100
- To: "public-i18n-mongolian@w3.org" <public-i18n-mongolian@w3.org>
On Thu, 6 Aug 2015 02:37:06 +0000 Greg Eck <greck@postone.net> wrote: > I am not quite clear on your reply. If we deal only with the textual > specification, are you saying that the actual current spec for U+1820 > should look like this with the "NotUsed" lines actually in the spec? > I am not talking about the implementation at this point. > > ISOLATE > 1820+NoFVS SpecificationDescription > 1820+FVS1 SpecificationDescription > 1820+FVS2 NotUsed > 1820+FVS3 NotUsed > INITIAL > 1820+NoFVS SpecificationDescription > 1820+FVS1 NotUsed > 1820+FVS2 NotUsed > 1820+FVS3 NotUsed > MEDIAL > 1820+NoFVS SpecificationDescription > 1820+FVS1 SpecificationDescription > 1820+FVS2 SpecificationDescription > 1820+FVS3 NotUsed > FINAL > 1820+NoFVS SpecificationDescription > 1820+FVS1 SpecificationDescription > 1820+FVS2 NotUsed > 1820+FVS3 NotUsed Human language is horribly ambiguous. 1) The 'NotUsed' entries are implicit. You don't need to list them in the specification. 2) The Unicode Specification says that 1820+FVS3 shall be treated the same way as 1820+NoFVS, for it is 'NotUsed'. However, you shouldn't believe anything you read in the Unicode Specification. 3) As 1820+FVS2 is defined for 'Medial', it is not clear what is allowed to happen for isolated, initial and final. The Unicode Standard 7.00 reads, in Chapter 13: "These format characters normally have no visual appearance. When required, a free variation selector immediately follows the base character it modifies. This combination of base character and variation selector is known as a standardized variant. The table of standardized variants, StandardizedVariants.txt, in the Unicode Character Database exhaustively lists all currently defined standardized variants. All combinations not listed in the table are unspecified and are reserved for future standardization; no conformant process may interpret them as standardized variants. Therefore, any free variation selector not immediately preceded by one of their defined base characters will be ignored." The reasonable interpretation is that 1820+FVS2 should be treated the same as 1820+NoFVS in isolated, initial and final positions. 4) It would be nice to see 'specification description' in Richard Ishida's document for +NoFVS. It doesn't tell us when an FVS is unnecessary. Richard. > > Greg > > > -----Original Message----- > From: Richard Wordingham [mailto:richard.wordingham@ntlworld.com] > Sent: Thursday, August 6, 2015 10:23 AM > To: Greg Eck <greck@postone.net> > Cc: jrmt@almas.co.jp; public-i18n-mongolian@w3.org > Subject: Re: New Thread - FVS Assignment MisMatch > > On Thu, 6 Aug 2015 01:56:08 +0000 > Greg Eck <greck@postone.net> wrote: > > > If we take one example from the font comparator site > > (http://r12a.github.io/scripts/mongolian/variants ) and look at > > U+1820. We see that Isolate+FVS1 is specified. Isolate+FVS2 AND > > Isolate+FVS3 are not specified as they are "don't care conditions". > > These two sequences are left to the judgment of the font designer > > to handle. > > No. > > <U+1820, FVS3> must be treated the same as U+1820, for the variation > sequence is not defined. Once <U+1820, FVS2> ceases to be specified > for any position, then the same will apply to <U+1820, FVS2>. > > It is not clear what should happen if only some positional variants > are defined for a variation sequence. > > Richard.
Received on Thursday, 6 August 2015 07:52:47 UTC