14 I think code review should be considered on-topic. This platform is well equipped for posts with potentially multiple longer answers and without the concept of an accepted answer, they can very well deal with different aspects of the code.

10 It seems very reasonable to me to allow users here to discuss codes. On the TeX.SX sites there are quite a few posts in which users post excerpts of a library and ask, say, details about \pgfdeclareshape. I think that this site is much more suitable for this task. First of all, as @samcarter already mentioned the (IMHO really stupid) accept-an-answer “feature” is not around. Second, I feel that the comment column here is much better equipped to get going. After all, one can post figures and it is more intuitive to have things side by side.

10 I think we can provide this service. But before that I’d like a feature to be implemented for this type, without which I’d find code review tedious:

5 [accepted fixed] \नमुना doesn’t work, literally

5 [accepted fixed] Simply loading the package in XeLaTeX causes some warnings

2 [Accepted Fixed] \if without \fi in the definition of \टंक

8 I didn’t test this, and I certainly have mixed up “gloss” and “transcription”, but I’d just do something like the following (I removed some unused \newcount and \newif, so don’t blindly copy this, I have no idea what you need – also I fixed your \@thirdofthree definition here, and dropped the unnecessary box assignment to measure the width):

9 Note: This review is not based on the code in above’s answer, but on commit 28c7fdc.

8 This is what I managed to typeset with package enotez.

6 I found the task interesting, but didn’t want to look into a package, so I coded it myself. I didn’t use LaTeX’s file-writing mechanism via the .aux file, so this works in a single pass (except for the hyper targets created with hyperref which might be misaligned on first pass, if you move \nirquotelist before the first \nirquote it would work as well, but needs two passes). If you want to use LaTeX’s writing mechanism instead I can provide code for it as well.

9 Sorry, this is not really a code review, more a complete different approach. The following uses pxpic for the parsing step and outputs boxes instead of pixels (with the right size).