[texhax] Generating index

[Karl Berry]

    Is that always necessary, or maybe it could be possible to create an
    automatical index only by TeX macros?

As far as I know, it is not practical to create a large index using only
TeX macros, because you'd have to implement sorting and a lot of other
things in TeX. 

    If so, are there any examples?

In the second item in the TFTI README, I suggest rewriting the index
generation so the standard makeindex program (or whatever else might be
out there these days, I haven't kept up) could be used.