[sil_bengali_phonetic] questions about Bengali keyboard

[srl295]

Background

Note: I'm converting this keyboard from https://github.com/keymanapp/ldml-keyboards-dev/blob/master/keyboards/sil-bengali/bn-t-k0-cldr-phonetic.ldml to LDML 3 but i think it originally came from sil_bengali_phonetic - there are some variations, but it's pretty similar.

More comments are on unicode-org/cldr#3368

U+09D7

keyboards/release/sil/sil_bengali_phonetic/source/sil_bengali_phonetic.kmn

Line 58 in 9e71c16

+ 'A' > U+09D7

Why is U+09D7 on the keyboard at all? It’s the right half of ৌ but shouldn't be used separately. how is it intended to be used?

09CC;BENGALI VOWEL SIGN AU;Mc;0;L;09C7 09D7;;;;N;;;;;
09D7;BENGALI AU LENGTH MARK;Mc;0;L;;;;;N;;;;;

maybe if there were separate keys for ে + ক + ৗ and that gets transformed into ক + ৌ ? ( = কৌ ) ?

question about A vs AA

From the PR linked,

@miloush asks:

Just to make it clear, the situation is:
A -> SIGN AA
SHIFT+A -> AU MARK

Q, A -> LETTER A
Q, SHIFT+A -> LETTER AA

(notably Q and long sign produce short letter unlike Q in combination with everything else)

[gsghyd]

As far as I can tell U+09d7 is completely redundant, except perhaps when you want to quote the right half of the mātrā (combining vowel form) and write about it.