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Message-ID:  <4B59B86F.8070007@morningstar2.co.uk>
Date:         Fri, 22 Jan 2010 14:38:39 +0000
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From: Joseph Wright <joseph.wright@MORNINGSTAR2.CO.UK>
Subject: Re: Collision between mathtools.sty and expl3
To: LATEX-L@listserv.uni-heidelberg.de
In-Reply-To:  <A0EC36FA-07DB-4D5B-B652-487C829D1D93@yahoo.de>
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Status: R

On 22/01/2010 14:20, Philipp Stephani wrote:
> Hello,
>
> mhsetup.sty (included by mathtools.sty) defines a few macros that expl3 wants to define anew, resulting in error messages.
>
> \documentclass{minimal}
> \usepackage{mathtools}% or mhsetup
> \usepackage{expl3}% error
> \begin{document}
> \null
> \end{document}
>
> This results in the following errors:
>
> % This is a LaTeX bug: check coding!
> % ! Command name `\if_num:w' already defined! Current meaning: \ifnum.
> % \msg_kernel_bug:x ...oding!}\tex_errmessage:D {#1}
> %
> % l.56 \cs_new_eq:NN \if_num:w
> %                                        \tex_ifnum:D
>
> % This is a LaTeX bug: check coding!
> % ! Command name `\if_case:w' already defined! Current meaning: \ifcase.
> % \msg_kernel_bug:x ...oding!}\tex_errmessage:D {#1}
> %
> % l.57 \cs_new_eq:NN \if_case:w
> %                                        \tex_ifcase:D
>
> % ! This is a LaTeX bug: check coding!
> % ! Command name `\if_dim:w' already defined! Current meaning: \ifdim
> %
> % For immediate help type H<return>.
> %  ...
> %
> % l.169 \cs_new_eq:NN \if_dim:w
> %                               \tex_ifdim:D
>
> The macros \if_num:w, \if_dim:w, and \if_case:w are defined using \cs_new_eq:NN.  Maybe you want to change this into \cs_set_eq:NN, or fix mhsetup.sty accordingly.
>
> Regards,
> Philipp
>

Hello Philipp,

This is because Morten's stuff has up to now used it's own expl3-like 
stuff internally. The team as a whole can't change things, unless of 
course Morten deputises the job to someone!
--
Joseph Wright