- From: Tony Graham <tgraham@mentea.net>
- Date: Thu, 27 Feb 2014 12:22:30 -0000 (GMT)
- To: public-ppl@w3.org
On Wed, February 26, 2014 10:43 pm, Kevin Brown wrote: > Sorry for being the new person to the party and now asking (what may > appear > to be) stupid questions. Not a problem: if it's not obvious to you, then there's probably also other people that don't find it obvious, so more explanation is going to be generally useful. > I am trying to understand what this is all about. I have read this page: > > https://www.w3.org/community/ppl/wiki/XSLTExtensions > > This seems to be an extension that runs the formatting engine completely > to > get the area tree for the whole document and then make decisions on that > result. > > Am I correct that is what they does? Yes. The FO that you process to get an area tree doesn't have to be from the entire source document, of course. > Essentially a function in XSLT that would need to get the entire area tree > and has some functions to return certain things from that area tree. Yes. The functions for getting things from the area tree are to save the stylesheet writer from having to know all of the ins and outs of a formatter's area tree XML and, ideally, to make stylesheets that use the functions portable between XSL-FO formatters, which currently they are. Exactly what functions are useful is still an open question [9]. The potted history of it all is: - Patrick Gundlach challenged [1] that the FO processing model doesn't support 'advanced requirements' because it doesn't support feedback - Jirka Kosek observed [2] that multi-pass processing isn't uncommon and postulated that it could be done with an extension function - Arved Sandstrom took on doing it for FOP [3] and produced versions for running FOP from Xalan and Saxon [4] - I did the first example of running the extension function multiple times in one transform [5] and also modified Arved's code to produce extension functions for running AHF from Saxon and Xalan [6], and, with a deadline looming, did the XSLT changes to use the current accessor functions that hide the area tree details [7] - Markus Wiedenmaier made a version for running AHF from Microsoft's XSLT processor [8] Regards, Tony. -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- Mentea XML, XSL-FO and XSLT consulting, training and programming [1] http://lists.w3.org/Archives/Public/public-ppl/2013Feb/0082.html [2] http://lists.w3.org/Archives/Public/public-ppl/2013Feb/0088.html [3] http://lists.w3.org/Archives/Public/public-ppl/2013Mar/0006.html [4] http://lists.w3.org/Archives/Public/public-ppl/2013Mar/0036.html [5] http://lists.w3.org/Archives/Public/public-ppl/2013Jul/0000.html [6] http://lists.w3.org/Archives/Public/public-ppl/2013Dec/0001.html [7] http://lists.w3.org/Archives/Public/public-ppl/2014Feb/0008.html [8] http://lists.w3.org/Archives/Public/public-ppl/2014Feb/0041.html [9] http://lists.w3.org/Archives/Public/public-ppl/2014Feb/0033.html
Received on Thursday, 27 February 2014 12:22:52 UTC