A framework for style sheet experiments/subsets?

Albert Lunde (Albert-Lunde@nwu.edu)
Thu, 27 Jul 1995 12:55:41 -0500 (CDT)


Message-Id: <199507271755.AA025317741@lulu.acns.nwu.edu>
Subject: A framework for style sheet experiments/subsets?
To: www-style@www10.w3.org, www-html@www10.w3.org
Date: Thu, 27 Jul 1995 12:55:41 -0500 (CDT)
In-Reply-To: <199507271704.NAA18618@clark.net> from "Mike Batchelor" at Jul 27, 95 01:04:25 pm
From: Albert-Lunde@nwu.edu (Albert Lunde)

> > >Comments?  Ideas?  Should I present a more technical specification?  I would
> > >imagine the language would be a touched-up subset of the current CSS proposal.

I assume you mean:

http://www.w3.org/hypertext/WWW/Style/css/draft.html

I guess this seems as reasonable as any other place to start.

I'd suggest that before encouraging experimentation, a couple
of things should be addressed.

If there are going to be multiple style-sheet languages or dialects
(as many suggest, though I have my doubts) we should try to make
clear how the correct style sheets and "dialect" can be determined
with HTML and HTTP. I'd like a consistent mechanism defined for this
early on if everything else is going to be babble.

If we write up a subset of a style sheet language, we should try
to define a precise syntax/grammer (with BNF or whatever) for
parsing the language, and if possible make this general enough
to deal with the whole language. (Some other proposals may
address this, but I didn't see anything in the CSS document
about grammer.)

We ought to address (as in HTML or more so) the question of dealing with
unknown extensions (and distingushing them from errors).

It would also be good to consider language features that
make it easier to recover from/localize parsing errors.

Either requiring a statement terminator like a semi-colon
or adopting a one-statement-per-line syntax with an explicit
continuation indicator would help in this context.

And even though we may not want to encourage fancy stuff
in a simple subset, something may need to be said about
the processing model of the language to make conditional
or context-dependent features work consistently. I.e.
is this a purely declaritive language, a procedural language
or what?

(Pardon me if I'm going over old ground here: I just want
to stress that a well-defined framework is important when
we start talking about many implementations.)

-- 
    Albert Lunde                      Albert-Lunde@nwu.edu