Message-ID:  <417f4014@corona.oche.de>
Reply-To: Mailing list for the LaTeX3 project
              <LATEX-L@URZ.UNI-HEIDELBERG.DE>
Date:         Sat, 4 Dec 1999 12:23:54 CET
From: Achim Blumensath <blume@CORONA.OCHE.DE>
Sender: Mailing list for the LaTeX3 project
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To: Multiple recipients of list LATEX-L
              <LATEX-L@URZ.UNI-HEIDELBERG.DE>
Subject:      Re: Classes -- a generalization of templates
Status: R

Hans Aberg wrote:
> Here is a possible generalization of the templates in the
> http://www.latex-project.org/talks/tug99.pdf document to classes. The
> point with the class dogma is that one has data with certain structure
> that one wants to describe, and that it helps that description (as it
> lessens programming errors, diminishes the need for repetitive low-level
> programming, etc).

Even if the template system reminds of object-oriented programming at first
glace, it is something completely different. Templates are just commands
which are parameterised; an instance provides the actual parameters for the
command. It doesn't make sense to subclass a template. You have to write a
completely new template if you want to add new parameters.

I don't think that an object-oriented approach is appropriate for LaTeX.
Objects are entities with an internal state capable of sending and
responding to messages. Thus, they are active elements. A text document
on the other hand is something static. It consists of text enriched by
meta-data describing its layout. LaTeX translates this static description
into some lowlevel format. Thus, basically LaTeX is a set of rules
determining this translation, i.e., a set of commands to perform this
translation. Therefore, IMHO a command-based system like templates is
much more appropriate in this context. Some work with the new system has
confirmed this impression.

Achim
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