I'm trying to establish a workflow for a LaTeX project and haven't figured out how to use makeidx or imakeidx packages to sort UTF-8 encoded index by languages not covered in the section supported languages/codepages of texindy.
So I decide to run my main tex file with \makeindex in the preamble and wrote a script [1] that overwrites the .idx file to my liking.
Now I have to convert the .idx into .ind, but everytime I invoke makeindex or texindy they output .ind files that changes the order specified in my .idx file.
Is there a way to ask makeindex or texindy to generate .ind file in accordance to the order of entries specified in the .idx file?
Is there a way to provide custom groups that are not really based on letters, preferably by further modifying the .idx file or calling texindy? I realize that
\lettergroupexists.
[1]: Locale-aware sorting of tuples by first splitting each row in .idx by '!'