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Date: Thu, 13 Jul 1995 22:45:40 +0200
From: Frank Mittelbach <mittelbach@MZDMZA.ZDV.UNI-MAINZ.DE>
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To: Multiple recipients of list LATEX-L <LATEX-L@VM.URZ.UNI-HEIDELBERG.DE>
Subject: Re: [Q] modguide.tex policy
Status: R

Frank Bennett writes:
 > Now here's my puzzle for the team.  Does this breach the terms
 > set down in modguide.tex: is this `modification of the contents
 > of a file'?  As I read it, it is not, technically, a breach.

as David pointed out it is not.

 > But suppose the LaTeX kernel is upgraded, in a way that affects
 > the internal structure of the \@footnotetext black box, perhaps
 > to add other interface flags.  Had I *not* redefined this
 > internal, Camel would work with the new version.  But as it
 > stands, Camel would redefine this internal command, wiping out
 > the new interface flag, and possibly breaking LaTeX itself.

this is a danger but there is no sensible way to avoid it. however in
any case the user document will behave the same way on two different
sites (with the same release of LaTeX) it will break or it will work
:-)

 > So maybe modguide.tex *should* make this a breach.  But there's
 > no other way to get the functionality needed by this package.

there are two helper functions in LaTeX2e which should make things a
little better: \CheckCommand and \CheckCommand*

if you put the original definition of the macro you intend to redefine
into a a \CheckCommand then your package will output a warning when
the internal changes one day. (the star form is for non-long
definitions, eg done with \def or with \newcommand* the other for
macros defined to be \long, eg \newcommand)

this is not perfect but without putting hooks everywhere which is not
really a solution with TeX we have to live with modest redefinitions
for special applications

frank