Message-Id: <9311111052.AA18022@sc.ZIB-Berlin.DE>
Reply-To: Mailing list for the LaTeX3 project <LATEX-L@vm.urz.Uni-Heidelberg.de>
Date:         Thu, 11 Nov 93 11:37:31 +0100
From: Frank Mittelbach <MITTELBACH@MZDMZA.ZDV.UNI-MAINZ.DE>
Sender: Mailing list for the LaTeX3 project <LATEX-L@vm.urz.Uni-Heidelberg.de>
To: Multiple Recipients of <LATEX-L@vm.urz.Uni-Heidelberg.de>
Subject:      Re: new extension for files
Status: R


 Emilio C. Lopes said:

> What do you think about "nf" or "s2e" or etc. *IN THE EXTENSION* ?:
>
>      times.sty ---> times.s2e
>
> Doesnot seem a good idea? Any problems with it?

we did thought of that and in fact had many discussions about it. We
finally decided afainst it except that we will distinugish class files
(formerly major document styles) by the extension .cls from packages
(with the extension .sty).

*The reason lies in  the question of compatibility*

As I said before style files for LaTeX209 will work under 2e. However,
when we change their extension a lot of them won't. Here is why:

- There is no problem to define a command \usepackage{foo} that looks for
foo.pkg and if it can't find it tries foo.sty as a compatibility solution.

- There is also no problem to handle \documentstyle[...]{...} and pick
up the right files whatever extension they have.

However, many style file do have direct input statements in them
loading other styles to extend or slightly modify them. Now all such
styles would break if we switch to new extensions in LaTeX2e.

The consequence of this is:

a) either you end up a system which is not compatible (ie where the
   site maintainer needs to change a lot of files to make them work with
   latex2e)

b) or you come along with an enormous amount of .sty files that
   contain only \input .pkg. For example, something like the array
   package would need to provide array.pkg (containing the code) but
   also array.sty to avoid breaking all those styles that load it directly.

c) This would be a situation that we would then have forever.


The same is true for essentially for class files, but here the number
is much smaller and so we came to the conclusion that the advantages
of distinguishing something essentially different from packages by
its extension, outweights the need to provide an additional
compatibility level.

Frank