User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-GB; rv:1.9.2.13)
            Gecko/20101207 Thunderbird/3.1.7
MIME-Version: 1.0
References: <4D20D031.7040803@gmx.de> <4D20DAE9.3070306@morningstar2.co.uk>    
            <DE9B7720-FDD0-4CF1-B66F-EB4DC7333D97@yahoo.de>                    
            <4D21D4CA.70703@morningstar2.co.uk>                      
            <2F1A4A24-7C35-4C2A-8E80-115DCD9510DF@YAHOO.DE>                    
            <4D21F6CE.10504@morningstar2.co.uk>                      
            <19748.63170.237158.614517@morse.mittelbach-online.de>           
            <FA69A517-71EB-4F6B-93E1-BE494B956AA6@gmail.com>
            <4D257ADD.5030101@morningstar2.co.uk>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Message-ID:  <4D26D308.5050904@morningstar2.co.uk>
Date:         Fri, 7 Jan 2011 08:47:04 +0000
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: Joseph Wright <joseph.wright@MORNINGSTAR2.CO.UK>
Subject: Re: \int_eval:n versus \dim_eval:n/skip_eval:n [was Re: l3luatex module]
To: LATEX-L@listserv.uni-heidelberg.de
In-Reply-To:  <4D257ADD.5030101@morningstar2.co.uk>
Precedence: list
Status: R

On 06/01/2011 08:18, Joseph Wright wrote:
> I've gone back and forward through this, and I think in the end this is
> the best plan. In the end, expl3 should be designed 'on its own merits',
> and that may mean that some mixed plain TeX\expl3 cases are a little
> awkward. For what we want, an expandable \int_eval:n makes most sense,
> and by logical extension \dim_eval:n and \skip_eval:n should also be
> expandable.
>
> What we do need to do is to make sure that this is clear in the
> documentation, as Philipp has pointed out. Something like
>
> After two expansions, \int_eval:n yields a <integer donation> not an
> <internal integer>. As a a result, it will require suitable
> termination if used in a \TeX-style integer assignment.
>
> and a similar statement for dim and skip cases.

This is now done in the SVN: I'll send it to CTAN in a few days.
-- 
Joseph Wright