Message-Id: <199402041826.AA22579@mail.cs.tu-berlin.de>
Reply-To: Mailing list for the LaTeX3 project <LATEX-L@DHDURZ1.BITNET>
In-Reply-To:  David_Rhead@VME.CCC.NOTTINGHAM.AC.UK Fri, 4 Feb 1994 12:10:29 GMT
Date:         Fri, 4 Feb 1994 18:24:32 GMT
From: Charles Wells <cfw2@po.cwru.edu>
Sender: Mailing list for the LaTeX3 project <LATEX-L@DHDURZ1.BITNET>
To: Multiple recipients of list LATEX-L <LATEX-L@DHDURZ1.BITNET>
Subject:      Re: Additional features
Status: R

> Getting back to LaTeX3 ...
> The question of
>      If it is a choice between "getting things right" or "backwards
>      compatibility", does one insist on "backwards compability"?
> has been asked before, and I think the consensus was
>      No.  Get it right.

One of the most important amenities that Latex3 can have is lots
of hooks into the internal code.  Example:  Michael Barr and I
produced our text "Category Theory for Computing Science" using
LaTeX.  We designed some macros to allow us to write things
like

\exer Prove Fermat's Last Theorem
\answer Somebody else already has.

so that \exer acted like an \item to print the exercise with a
number, and with \answer acting like \index to put the answer in
a separate file.  We wanted the answer file to contain headers
such as "Answers to Chapter 5"  and "Answers to Section 5.3". To
handle the chapter output we had to redefine \@chapter to output
the header to the answer file.  The alternative would have been
to defined another command \chapteranswerheadingout (or
something) which we then had to remember to insert after every
\chapter.  (Similar remarks for \section, although we did not
actually do that for the answers there was a spacing problem we
had to handle by redefining \@section.)

What is needed there is an \everychapter command.  LaTeX3e
should probably have an \everyfoo command automatically
generated by every definition \foo that calls \@section.

In a more detailed way, we should be able to insert code to run
BEFORE every section (chapter, whatever) and immediately AFTER
every section.  Similarly to handle recent complaints the \list
command should have a way to run code before the list starts,
before each item, after each item, and after the last item.

Perhaps this is already in progress.  But in any case I think
this sort of vectoring is one of the most important
modifications the LaTeX3 committee can make.

--
Charles Wells
Department of Mathematics, Case Western Reserve University
10900 Euclid Avenue, Cleveland, OH 44106-7058, USA
216 368 2893