References: <20170731.162337.688577912214660894.wl@gnu.org>
            <63285c18-e1f1-11b7-8876-dab4c8ea661a@latex-project.org>
Mime-Version: 1.0
Content-Type: Text/Plain; charset=utf-8
Message-ID:  <20170801.191054.1443312899605260513.wl@gnu.org>
Date:         Tue, 1 Aug 2017 19:10:54 +0200
Reply-To:     Mailing list for the LaTeX3 project
              <LATEX-L@LISTSERV.UNI-HEIDELBERG.DE>
Sender:       Mailing list for the LaTeX3 project <LATEX-L@LISTSERV.UNI-HEIDELBERG.DE>
From:         Werner LEMBERG <wl@GNU.ORG>
Subject: Re: \usepackage problem with LaTeX 3
To:           LATEX-L@LISTSERV.UNI-HEIDELBERG.DE
In-Reply-To:  <63285c18-e1f1-11b7-8876-dab4c8ea661a@latex-project.org>
Precedence: list
Envelope-To: <rainer.schoepf@GMX.NET>
Content-Transfer-Encoding: 8bit
Status: R


> The way packages guard against this problem is simply by making sure
> that \usepackage or \RequirePackage will execute the external code
> only once.

Yep.

> [...] the mechanism for this is fairly simple: the loader looks in
> 
>    \csname ver@<filename>\endcsname
> 
> and if that is \relax the it loads the file.

Thanks for confirmation.

> Maybe we should have a declaration
> 
> \ThisCodeReplacesPackage{foo}{date}
> 
> for the above but we don't (yet)

memoir.cls uses `\EmulatedPackage', as Will pointed out – maybe it
makes sense to stick with this name?

> I don't really see the need to clone fontspec and fontspec-xetex
> especially given that fontspec does so little and you aren't really
> changing it.

Well, it's the solution with the least code change...


    Werner