[HarfBuzz] Corner case wrt to repeating Malayalam vowel sign OO

[Pravin Satpute]

On 02/28/2013 02:46 PM, Jonathan Kew wrote:
> On 28/2/13 01:09, Behdad Esfahbod wrote:
> > On 13-02-27 05:41 PM, Cibu Johny (സിബു) wrote:
> >>
> >> When
> >> ​MALAYALAM ​
> >> VOWEL SIGN OO is repeated after a consonant, third one is displayed
> separately
> >> with a dotted circle. It should have behaved like the second OO
> sign. Sample
> >> text: കോോോ
> >>
> >> ​If there is a imposed upper limit for the count of repeating vowel
> signs,
> >> something close to 10 would be useful.​
> >
> > Right...  We used to have no limit, but to be closer to Uniscribe we
> limited
> > consonants to about 5 per syllable, and matras to 4.  Now, split
> matras count
> > two each.
> >
> > I'll go ahead and lift the limit again.
> >
>
> I wonder whether it really makes sense to allow multiple matras in
> -all- positions. I believe I've seen Devanagari examples similar to
> Cibu's Malayalam comic, where a right-matra is repeated to suggest a
> loooooong sound. But left-reordering matras? Split matras? Above- or
> below-matras? The idea of repeating these indefinitely when writing
> seems much less plausible.
>
> Cibu, the example you showed looks like it does not actually repeat a
> split-vowel matra; rather, it appends a repeated U+0D57 "Malayalam AU
> length mark". Do people actually repeat the full range of matras in
> their entirety, and if so how are repeated matras written on all the
> various sides of the base? Or is this practice restricted to
> "trailing" (right-attached) signs that can reasonably be appended to
> the cluster without affecting the rest of the glyphs?

Rather than altering script grammar rules, can we handle these
exceptional stuff with ZWNJ/ZWJ?
I am agree with jonathan, that it is mostly right hand side of words
which gets elongated. So i think might be with Regular syllable one can
simply use ZWJ and append as many matras as he wants. That will be
ultimate solution.

At least in Devanagari i have not seen syllable having more than single
matra other than Comics stuff mentioned in this case.

Best Regards,
Pravin Satpute