Counting Devanagari Aksharas

[Richard Wordingham via Unicode]

On Fri, 21 Apr 2017 00:08:24 -0500
Anshuman Pandey via Unicode <unicode at unicode.org> wrote:

> > On Apr 20, 2017, at 8:19 PM, Richard Wordingham via Unicode
> > <unicode at unicode.org> wrote:

> > Now imagine you're
> > typing Vedic Sanskrit, with its clusters and pitch indicators.  
 
> I tried typing Vedic Sanskrit, and it seems to work:
 
> http://pandey.pythonanywhere.com/devsyll

That should demonstrate nothing relevant if you type correctly first
time.  The issue comes when you mistype and have to correct, to give
the usual worst case, the first letter of a conjunct.  Now, I looked at
your page in Firefox on Ubuntu, and I found the cursor seemed to move
by extended grapheme cluster.  That means that to change a consonant
you have to retype the following marks.

I did find two issues with your analyser.

Firstly, it broke श्रीमान्‌को into श्री·मा·न्को, which does not
concatenate back to the original.

Secondly, you have a problem with ANUDATTA.  You are not accepting
<U+0924, U+0902, U+0952> as a syllable.  Perhaps you believed
https://www.microsoft.com/typography/OpenTypeDev/devanagari/intro.htm
as to the structure of a Devanagari syllable.  I suspect ANUDATTA as a
consonant modifier went out when U+097B DEVANAGARI LETTER GGA and the
like came in. 

Richard.