[HarfBuzz] harfbuzz: Branch 'master' - 2 commits

[Jonathan Kew]

On 15/5/14 01:19, Martin Hosken wrote:
> Dear Behdad,
>
>> The previous grammar for medial group was allowing an Asat after
>> the medial group only if there was a medial Wa or Ha, but not if
>> there was only a medial Ya.  This doesn't make sense to me and
>> sounds reversed, as both medial Wa and Ha are below marks while
>> Asat is an above mark.  An Asat can come before the medial group
>> already (in fact, multiple ones can.  Why?!).  The medial Ya
>> however is a spacing mark and according to Roozbeh it's valid to
>> want an Asat on the medial Ya instead of the base, so it looks to
>> me like we want to allow an Asat after the medial group if there
>> *was* a Ya but not if there wasn't any.  Not wanting to produce
>> dotted-circle where Windows is not, this commit changes the grammar
>> to allow one Asat after the medial group no matter what comes in
>> the group.
>
> Might be worth reading UTN#11 on this. If Roozbeh has documentary
> evidence of languages where the asat really does go over the
> medial-ya rather than the consonant, then I would love to see it. The
> reasoning behind having the asat before the medial is because asat
> marks reduplication in that context in Burmese. It makes no sense to
> have an asat on a medial since people don't want to kill a sequence.
> Try saying a word final kw, you might be able to wrap your tongue
> around it, but it doesn't fit any languages around here.

But regardless of whether it "makes sense" for any known orthography, 
ISTM that provided the medial is a spacing glyph, there's a clear visual 
distinction between <base><asat><medial> and <base><medial><asat>. So 
allowing both does not introduce a problematic spelling ambiguity, and 
it leaves users of the script free to produce whichever of the two 
written forms they wish.

Recalling that Unicode encodes (and OpenType renders) the graphical 
elements that make up scripts, and not the linguistic content of 
particular languages, I think it's correct, in general, for the grammar 
to allow a sequence like this.

JK

>
> The aim of UTN#11 is to come up with a consistent ordering of
> diacritics that balances the need for consistency with
> appropriateness of spelling. For the most part it's OK, if a little
> complex. But that was because of pressure to put linguistic purity
> over technical expediency.
>
> IOW, I think the change you have made is probably a wrong move :)
>
> Yours, Martin _______________________________________________
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