[tex-hyphen] pattern stability (was: gswiss in language.dat)

[Mojca Miklavec]

On Thu, Dec 5, 2013 at 7:09 PM, Stephan Hennig wrote:
>
> I think, we've had this discussion before, but let me ask again:  What
> is the current plan regarding pattern stability?

No special plans at the moment.

In theory the patterns are not even stable for pdfTeX (I never prevent
the authors to submit patches other than for hyphen.tex ;), but in
practice this is hardly ever a problem since basically no patterns
other than German (and a very very few others with tiny modifications)
ever change.

The German patterns are also the single exception where 8-bit and
Unicode engines (+pTeX) load different patterns.

> I remember an argument
> that 16-bit-engine patterns may change arbitrarily as long as neither
> XeTeX nor LuaTeX are declared stable (reach version 1.0).  Is there any
> plan to freeze patterns for those engines eventually or will they never
> be frozen?

Honestly I don't know. But I imagine that if one day special Dutch
patterns with support for all kinds of hyphenation exceptions (in the
spirit of your "was TeX (bislang) nicht kann") come out, the LuaTeX
team won't be willing to stick with the old patterns or require the
users to type something like
    \usepakage[patterns=specialdutch]{hyph-xyz}
to switch to the advanced patterns.

Maybe this is a question that needs to be addressed for each language
separately. I mean: even if LuaTeX becomes stable one day, support for
some languages is explicitly experimental (like Lao) and users of
those languages probably want to improve the patterns over time. And
if special groups of users require stability, all that needs to be
done is to stop updating patterns for that language. Since there is
usually a single author of the patters, this can easily be achieved.

Provided how many packages change on daily basis and how many get
removed from TeX Live or undergo other significant changes, it gets
more and more difficult to talk about 100% backward compatibility
unless one sticks with the same old distribution.

>> I'm not involved in polyglossia or Babel, but the author of Babel
>> recently decided to 100% outsource maintenance of language
>> definition files.
>
> Can you point me to such a statement?

I think Javier is following this list or you can ask him directly, but
http://www.tex-tipografia.com/babel_news.html says for example:

Starting with this version, babel has been separated in a core (or
“base”) part, and contributed language-specific packages, which should
be maintained by its contributors. In particular, it shall be no
longer necessary to synchronize Babel core releases with releases of
Babel language files.

Mojca