Allowed characters in package names

[Ian Jackson <ian@chiark.chu.cam.ac.uk>]

Comments are invited:

Currently package names must start with an alphanumeric, must be at
least two characters, and may contain only only alphanumerics and the
characters - + . @ : = % _ (that is, hyphen, plus, stop, at, colon,
equals, percent and underscore).  (This language is from the
guidelines, and is enforced by dpkg-deb and dpkg.)

There are currently no packages using any punctuation except
- + . _ (hyphen, plus, stop, underscore).

The two packages using `_' are all recent additions to the development
tree: ucbmpeg_play, xterm_color and npasswd_boulder; most other
packages use `-' to separate words.

The only packages using `.' are ncurses3.0 and ncurses3.0-dev;
arguably ld.so should use it too.

The only package using `+' is libg++.

I propose to make the following changes:

* All punctuation except - + . _ will be forbidden. [1]
* Trailing hyphens will be forbidden.
* `_' will be deprecated. [2]

I want to do this so that our package names look more consistent and
so that mapping package names onto filenames on some systems is
easier.  It needs to be done ASAP if it is to be done at all.

Should `.' also be deprecated ?

Ian.

[1] Forbidden means that dpkg will not accept such packages, dpkg-deb will
refuse to build then without the --nocheck flag, and the guidelines
will say that they are not allowed.

[2] Here, deprecated means that dpkg will accept and install them
without complaint but that dpkg-deb will refuse to build them without
--nocheck and that the guidelines will be amended to remove these
characters into a footnote.