Re: W3C-transformation language petition

[Chris Maden <crism@xxxxxxxxxxx>]

[Ian Hickson]
> What about an aural rendition?
> 
> Will XSL be able to cope with alternative (non graphic) media? CSS
> can. This is quite an important issue.

Short answer: XSL must because of the W3C's commitment to the WAI.
It's a procedural requirement.

Longer answer: I believe that XSL will be better able to cope with it
than CSS because the formatted output is structured.  CSS provides
aural properties on an element, and I believe that XSL should do the
same with its FOs: for instance, fo:block would have a default
pause-before and pause-after of about 300%.  There is not agreement on
this proposal.

But consider the ability to structure the formatted document,
providing HTML-<object>-like sets of alternatives, or audio and visual
formatting objects with specified relationships to each other.

Media dependency is not an issue that's been addressed by the WG yet,
but it is listed as an issue in the drafts (I believe; the W3C server
is down right now!).

> Quite seriously, what is it that in the opinion of FO proponents is
> missing from CSS? (Other than tree transformation, obviously.)

Structured output is a big thing.  XML syntax is ideal for
representing crosslinked trees, and a formatted document is full of
such relationships (page number dependencies, allocating sidebar space
on the screen, "above" or "below" conditional text).  CSS could be
extended to handle such situations, but I believe that that would
damage the simplicity that makes it valuable.

> Another problem with the concept of using XSL to style documents is
> that XSL is not, AFAICT, dynamic (unless you go in with the DOM and
> directly change the tree structure, which is quite a drastic thing
> to do, and certainly isn't quick and easy).

Not yet, anyway.  There are a number of proposals to specify "active"
formatting objects in XSL.  I believe that once again a structured
formatting specification is better suited to handling tasks like this
than a decorated version of the source tree.

-Chris
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