Re: Bug#793067: Bug#792328: info: can no longer find the Emacs manual

[Rob Browning]

Karl Berry <address@hidden> writes:

> Here's what I don't get: suppose there are two versions of Emacs
> installed, emacs-x and emacs-y.  Presumably Debian (and anyone else) has
> some method for the user to choose which one is invoked by just "emacs".
> Can't that method, whatever it is, also switch the Info files that are found?

Among other things, I don't think that'd really be feasible on a
multi-user system.  I don't want to change the docs (and currently the
default #! version as well) for everyone on the system just because I
want to check out the GCC 5 info pages.

At least on Debian the normal method is update-alternatives, which can
only be invoked as root, and changes the defaults globally.

Taken as a whole that seems awfully heavy handed if all you want to do
is read the Guile 2.2 docs while still defaulting to 2.0 in all other
ways (i.e. for #!/usr/bin/guile).

And even if update-alternatives worked per-user, it would still have to
be augmented to accommodate the documentation independently from any
"#!/..." links, because I don't want to switch even my per-user default
executables just to read newer/older docs.

I'm also not sure how you would address the #! links per-user, unless
they were required to be of the form "#!/usr/bin/env ..." system-wide,
or similar.

Perhaps it's naive, but I feel like I might just want a dir like this so
that I can find what I want and don't have to change global state and/or
restart the viewer just to read different versions:

  * Emacs 24 ...
  * Emacs 25 ...

  * GCC 4.9 ...
  * GCC 5.0 ...

  * Python 2.7 ...
  * Python 3.4 ...

Then the internal refs would be appropriately versioned, and the readers
would jump to the appropriate version by default. i.e. the Emacs 24
pages would link internally to the emacs24-calc or calc-emacs24 or
whatever.

Perhaps the various calc versions might percolate up to the top too:

  * Calc W.X
  * Calc Y.Z

And "info calc" might even just show me that if I wasn't more specific,
say via "info calc/W.X".

Though at the moment, I don't really care about the details of the
interface as long as there's a reasonable way to find the versions I
want.

> I just don't see how Texinfo can help to solve the
> multiple-version-packaging problem.

I'd be a bit surprised if in the long run Texinfo doesn't plan to
accommodate installing and reading the documentation for multiple major
versions.  For example, in the GCC world it's certainly reasonable to
expect that you might need to work with both 4.9 and 5.0, or with 2.7
and 3.4 in the Python world, etc.

FWIW, if I'm reading it right, it looks like the Debian GCC 5 info pages
may be using gcc-5 and gccint-5 style refs.

Thanks
-- 
Rob Browning
rlb @defaultvalue.org and @debian.org
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