Re: WWWWW Notes
Steve Heaney <Steve.Heaney@delft.sgp.slb.com>
Date: Fri, 13 Aug 1993 20:11:14 +0200
From: Steve Heaney <Steve.Heaney@delft.sgp.slb.com>
Message-id: <199308131811.AA16865@mordred.delft.sgp.slb.com>
To: sanders@bsdi.com
Subject: Re: WWWWW Notes
Cc: www-talk@nxoc01.cern.ch
Status: RO
Tony Sanders <sanders@bsdi.com> writes:
> > A DTD describing an "abstract presentation information" (which Nathan
> > suggests) is no more or less than _another_ presentation format. Surely
> > we can aim higher that that.
> >
> > > As usual, my opinions only...
> The trick is to allow device independent presentation while still providing
> the most common semantics. HTML/HTML+ is ultimatly a presentation language
> and there is no way around it. If you cannot convert most DTD's to
> HTML/HTML+ then we are back to square one because it is *impossible* to
> include semantics for everything under the sun.
>
Nathan was suggesting disposing of semantic information altogether. That
is what I object to. There are clear advantages to identifying semantic
content.
The trouble with saying that HTML/HTML+ is ultimately a presentation language
is that is IMHO a bit short sighted. By adding structure to documents, you
open up a lot more possibilities. Presentation is one use, but why
exclude others by disposing of the semantic markup. Index building, search
in context etc.
> Will we ever be free of the SGML "presentation is evil, evil I say" party
> line? If you want anyone to be able to read your SGML then you have to
> have some presentation somewhere. HTML/HTML+ is a compromise between
> allowing as much semantic content as possible -- while still having a
> finite DTD -- but still allowing a wide variety of data to be encoded
> for (here is that evil word again) presentation.
>
I agree with you in that we can't expect to have an HTML+ DTD which has
all the semantic elements you would ever want. That should not preclude
trying to come up with a usable set however, with a facility for those
that don't fit.
> HTML/HTML+ is presentation with semantics, keep saying that over and over.
>
I would rather see it as semantics with presentation :-)
> On the other hand maybe you know something I don't. If you can write a
> DTD that does everything that everyone needs without using any presentation
> then get in contact with Dave Raggett <dsr@hplb.hpl.hp.com> and see what
> you two can work out. Oh, BTW, most of the actuall presentation
> is in what we are calling a "Style Guide" that is external to the
> HTML/HTML+ document and provides hints to the browser about how to
> render the document (so you can use the authors style guide, or your
> own personal favorite).
>
The style sheet idea is great. By extracting the information from the
document, you inevitably get more control for less effort. On this
subject, this has been the area of a lot of work in the SGML community -
coding presentation information. Are you familiar with the FOSI
standard (US DoD) or the DSSSL standard. I'm not suggesting adopting
them, but they may contain some useful ideas/pointers to the issues.
Dave and I have exchanged a few mails. I disagreed with the notion of
having the semantic content coded as attributes to <p> and <em>. This
makes the structure of the DTD very flat and I would rather see it more
hierarchical. The <cite> element is a good case in point. I would like
to see this as a container with say <author> <isbn> <publisher> etc as
sub-elements. More hierarchy, more structure, without compromising the
ability to add presentation information in any way.
It also leaves open the evolution of the DTD without the problem of
"Hell - how can I add a content model to an attribute". I.e. if you
code say <head> as an attribute, it can't then contain <title>, <isindex>
etc.
> When we talk about presentation in HTML+ we are mostly talking about tables
> and external graphical image layout (e.g., gif's). Someone should make
> a list of the presentation like elements in HTML+.
>
> --sanders
>