Message-Id: <199402101206.AA18282@mail.cs.tu-berlin.de>
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In-Reply-To:  <MAILQUEUE-101.940210092502.352@derwent.shef.ac.uk> (message from
              Mike Piff on 10 Feb 94 09:25:02)
Date:         Thu, 10 Feb 1994 10:43:59 GMT
From: David Carlisle <carlisle@cs.man.ac.uk>
Sender: Mailing list for the LaTeX3 project <LATEX-L@DHDURZ1.BITNET>
To: Multiple recipients of list LATEX-L <LATEX-L@DHDURZ1.BITNET>
Subject:      Re: A philosophical question about packages and options
Status: R

> ... Indeed, article is far too big a portmanteau to survive
> undivided,...

Mike, perhaps you should look at David Rhead's postings.
Much of the confusion you are having over options/packages is due,
exactly as you say, to the fact that article.{cls|sty} defines

* the `tags' an article may have,
* The default layout of those tags
* A mixed bag of tags which may optionally be defined
* A mixed bag of optional layout choices.

But it is not just article.cls. All 2.09 `main document styles' do
this.

> 2e is designed as a `consolidation' of existing 2.09 flavours. Most   <
> existing styles are supposed to work with it, with only minor changes.<
> So the 2e interface is not as `pure' `orthogonal'  (insert whatever   <
> words you want in this list) as it would otherwise be.                <

However an `option' in 2e is something *declared by the class/package*

So article.cls has an option 12pt to change the default font size and
spacing. It is declared in the file. so you can go
\documentclass[12pt]{article}

article.cls does  not declare any options to change the font families
used, so you can not go
\documentclass[times]{article}

however there are extension packages to add this functionality

\documentclass{article}
\usepackage{times}.

To find out what options a package supports, you just need to look at
the list of \DeclareOption commands in the file.

This distinction may be weak, but it is better than 2.09 where

\documentstyle[array,twocolumn,11pt]{article}

mixes up internal options defined by the class, options adding extra
functionality defined in external files...

And we were working under the constraint marked with > ... < above.

David