How to avoid conflictions in Info manuals

[Masao Uebayashi]

Hello,

I'm wondering how I can install GNU Emacs 20 and GNU Emacs 21 Info
files simultaneously.  There are some restrictions of Info I've found,

  * Category names has to be unique in a `dir' file.

  * Entry names has to be unique in a `dir' file.

  * ...

One solution, which Debian takes, is installing Info files into
subdirectories.  It looks like

  info/dir
  info/emacs20/emacs
  info/emacs20/emacs-1
  info/emacs20/emacs-2
  :
  info/emacs21/dir
  info/emacs21/emacs
  info/emacs21/emacs-1
  info/emacs21/emacs-2

And in info/dir,

  Emacs 20
  * Ada mode e20: (emacs20/ada-mode). The GNU Emacs mode for editing Ada.
  :
  Emacs 21
  * Ada mode e21: (emacs21/ada-mode). The GNU Emacs mode for editing Ada.
  :

The problem of this is that `install-info' can't uninstall entries
installed in subdirectories.  For example, if I invokes `install-info'
like

  $ install-info --delete emacs20/ada-mode

it assumes `ada-mode', the basename part of `emacs20/ada-mode', is the
entry.  (Debian can do that because they have their own `install-info'
written in Perl.)

Eli Zaretskii kindly suggested another solution that installing Info
files into _separate_ directories.  That is, GNU Emacs 20 Info files
and GNU Emacs 21 Info files have an own Info directory and a `dir'
respectively.  This possibly works (I have not tried,) but I don't
think it's a good idea to demand all users to add INFOPATHs by
themselves.

So now I would like to see just another suggestion from you.  If
nothing, I'll go to the latter...

Regards,
Masao