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RE: XSL-FO's semantics ARE those of presentation (was: storing info in XSL-FO)

From: Ian Tindale <ian_tindale@yahoo.co.uk>
Date: Thu, 5 Sep 2002 22:31:53 +0100
To: <www-style@w3.org>
Message-ID: <000101c25523$abdbcbc0$fc00a8c0@solstice>

{It appears that an ongoing and very interesting thread had the audacity to spring up while I was away in Jamaica for the duration of August. Having only just finished ploughing through the back email, I would like to interject the following:}

> -----Original Message-----
> From: www-style-request@w3.org [mailto:www-style-request@w3.org] On Behalf
> Of HÃ¥kon Wium Lie

[and a whole lot of other people, on various sides of the discussion]

> Sent: 16 August 2002 14:10
> How do you express that some text is a headline in XSL-FO? 
> Or that some string is a variable?

It should never be necessary to even know such facts. Such information is not vital or required to image said item to paper (or the user-agent). If you need to know, you're looking in the wrong place - you've gone too far, turn back. Return to the source.

> XFO, on the other hand, gives access to the text but information that
> can be used to decide if a word can be contracted or not is lost.

That's because such information isn't needed by this stage. If it were needed at all, it would've been at a preceding stage, which might govern exactly how the XSL-FO should take form (or in the mentioned case, how the OtherML would be transformed into). Such a decision making phase would not be appropriate so near to the user-agent, rather it would occur closer to the transformation end.

In fact, it might be argued that print is harmful because all electronically derivable semantics are lost. And worse - print is persistent. It hangs around for ages. How are we to ever search, catalogue or even use printed matter such as books? In fact, the written word, alphabets might be seen as harmful too, as they abstract entirely from the meaning of the word - both sonically and visually and as individual components. How are we ever to know what a word means if the definition is not to be derived by analysis of the sounds of the letters or shapes of the glyphs?

The point: The thing is, which semantics are important for which purpose? I see XSL-FO as being highly semantically loaded, but with respect to a different kind of semantic world than the original purpose of the editorial material when it might have existed in a more freeform 'data' state. The semantics of XSL-FO are purely and totally only concerned with which areas on a page should exist, what should exist within those areas and generally how the resulting pages should look. 

That is the task in hand - to present pages, and consequently the semantics have been 'transformed' if you will (typically at the transformation stage) from one of the original topic area to now one of how to make a page. In other words, whereas you'd normally separate presentation and content/semantics, the presentation now becomes the semantics in hand - the job that this XML vocab does IS presentation and nothing else. 

In the creation of pages for publication, it is never going to be important to discern outside purpose of any item on a page. To do that, one goes back to the source, prior to transformation, not at the page building phase. Thus we can see that XSLT (for example) transforms not only the document structure but also the document intent or purpose. 

This might be a semantic-related criticism levelled at PDF and PostScript, but in the case of 'normal' PostScript that might exist for a brief and transient period of time between QuarkXpress spitting it out and an imagesetter eating it then discarding it before issuing film, it is extremely unlikely that anyone or thing should ever need to know any 'higher' meaning regarding any of the strings of type, lines, arcs, boxes, beziers, characters etc. that are embodied with the PostScript. To me it's like trying to ascertain some higher individual meaning behind the electricity that powers the imagesetter. 

Ian Tindale
Received on Thursday, 5 September 2002 17:32:18 UTC

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