I think that it would be valuable if we had an environment index and a
control character index.
Sorry, but I disagree. I do not want multiple indexes. I think they
make things harder for readers, because they create multiple places to
look for the same information. (Indeed, I'd like to merge the concept
and command indexes. I inherited them.)
What I can agree with is that index entries could contain text
like " (environment)".
Since they are not so many,
Precisely because there are not so many, I don't think there is any
great problem with having the list in the text. A whole separate index
would be overkill to me. -k
