Re: syntax feedback

Subject: Re: syntax feedback
From: Paul Prescod <paul@xxxxxxxxxxx>
Date: Mon, 14 Dec 1998 15:46:04 -0600
"Simon St.Laurent" wrote:
> 
> Thank you for comparing my style sheet language of choice to a Metro.  I'd
> prefer that you referred to CSS as a (new) Volkswagen Beetle, and XSL as a
> Combine (heavy-duty farm equipment) of whatever brand you link.

I don't know of any company that makes both. I wanted to make the point
that the same organization can have two "stylesheet languages" and "markup
languages" just as a car company has various kinds of cars.

> >"Other than the fact that it goes really fast, the Camaro isn't very much
> >more interesting than the Metro." If you need a fast car (e.g. to satisfy
> >your ego or to catch Bad Guys) then you don't really have any choice and
> >thus there isn't any competition.
> 
> There's plenty of competition for development resources, I'm afraid.
> Microsoft seems to have the money to pour into both XSL and CSS, but for
> the rest of the world, supporting both is a difficult task.

Not true. CSS and XSL are to have a common formatting model. If so, CSS
can be "compiled" into an XSL stylesheet rather easily.

LI	{	display: list-item;	}

compiles to:

<xsl:template match="LI">
	<list-item>...</list-item>
</xsl:template>

Of course you don't compile to a real XSL file. You just share an
execution model internally. I predict that I could implement this
converter in less than a programmer-week.

> I'm glad I missed whatever the first spec was.  'CSS was never even a
> contender because it did not do transformations'. So why not build a
> transformation engine and layer CSS on top of it?

Because the input to a CSS processor is a document and a stylesheet. But
the output of the transformation is an *already formatted document* with
*no stylesheet*. Since the transformation part of XSL knows nothing about
CSS, I'm not clear how it would generate the CSS stylesheet.

I mean sure, if I'm implementing XSL on the server side then I might
generate XML with a known set of element types and use a pre-written CSS
stylesheet. That's a fine idea. But if it's on the client side, where does
the CSS stylesheet come from? Do I now ship an XML document AND an XSL
spec. AND a CSS stylesheet?

> What is it about XML that encourages the development of standards which
> mash together multiple layers of processing?  Why not keep transformation
> in one box, and formatting in the other, and let people who need both just
> use both layers?

That's exactly what the XSL spec does. There are two parts of the spec.
and they can be implemented independently. Sure, there may be good reasons
to have them as two different specs, but don't pretend that the XSL spec.
mashes them together. It very explicitly does not.

> That way, you'd avoid all of this sniping between the different style sheet
> communities, give developers a clear path on which to build, and make it a
> lot easier to move documents from one world (without transformations) to
> another (with transformations) without having to reinvent the wheel each time.

"Style sheet communities" are made up of people who have the option of
sniping or not. I'm not so worried about stopping them.

It would be great to make it easier to move from one to the other.
Standardizing the formatting model is one step. Writing CSS to XSL
conversion scripts is a second. You haven't formalized your proposal for
"layering" CSS, but I'm pretty sure that it doesn't look like Daniel
Glazman's language.

> >According to our own informal survey, these technologies are not in
> >contention, direct or otherwise. They are complementary.
> 
> Who is 'our'?  Just curious.

Yours and mine. You talked to Web hackers who thought that XSL was too
complex. I talked to people who had complex XML transformation projects
and they thought that CSS was too simple to be useful to them.

 Paul Prescod  - ISOGEN Consulting Engineer speaking for only himself
 http://itrc.uwaterloo.ca/~papresco

"Sports utility vehicles are gated communities on wheels" - Anon


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