arunk,
Tried out the following text in the test bed for testing
s (as in sangam), sh (shankara) and Sh (Shanmukha) along with the visarga feature you added;
karuNA kaTAkSha Ela upEkSha duShTa shikShaka shiShTa rakShaka - duHkhahara shiva kR.pALu susamskR.ta bhaktara poreyO ~nAna dIkSe ittu.
I have highlighed the errored spots below:
In Tamizh it shows up as:
கருணா கடாக்ஷ ஏல உபேக்ஷ துஷ்ட
ஷிக்ஷக
ஷிஷ்ட ரக்ஷக - துஃகஹர
ஷிவ க்ருபாளு சுசம்ஸ்க்ருத பக்தர பொரெயோ ஞான தீக்
செ இத்து.
In kannada it shows up as:
ಕರುಣಾ ಕಟಾ
ಕ್ಶ ಏಲ ಉಪೇ
ಕ್ಶ ದು
ಶ್ಟ ಶಿ
ಕ್ಶಕ ಶಿ
ಶ್ಟ ರ
ಕ್ಶಕ - ದುಃಖಹರ ಶಿವ ಕೃಪಾಳು ಸುಸ
ಮ್ಸ್ಕೃತ ಭಕ್ತರ ಪೊರೆಯೋ
ಙಾನ ದೀಕ್ಷೆ ಇತ್ತು.
I think there is inconsistency in handling s, sh and Sh ;
s - should be
ಸ in kannada,
ச or
ஸ் depending on the context in tamizh ( No doubt about that)
sh - should be
ಶ in kannada, and
ச, as for as I know

in tamizh (you might use S or Sh or whatever - as long as it gives consistent results in both scripts - AND - you tell the user beforehand how he should spell this sound
Sh - should be
ಷ in kannaDa should be
ஷ in tamizh (Again, you might use S or Sh .. but specify it first)
The samyuktAkshara 'ksha' is rendered correctly in tamizh script, but incorrectly in kannada
(kSa gives the correct representation in kannaDa script (
ಕ್ಷ ) but wrongly shows up as
க்ச in tamizh. kSha or ksha give the correct representation in tamizh (
க்ஷ ) but shows up as
ಕ್ಶ in kannaDa.
visarga looks good.
more about ~nAna and saMskR.ta in the next post.
-Ramakriya