Re: TeX vs XSL-FO

[FB...@wiley.com]

The major problem is that XSL-FO insulates the layout engine from the 
specific physical rendering. For example, you can't query the precise size 
of a heading and change the output based on the size and shape of the 
heading. But this is necessary if you want, say, a rule after a heading 
that is the width of the last line of that heading:
       Imagine a long heading with a short
       last line
       -----------

Of course, this is usually considered a feature: the same XSL-FO file can 
easily be rendered in various formats.

And this sort of detail is not necessary for technical manuals and 
business documents; but it become important when you're trying to meet the 
specification of layout artists who expect computers to be able to do 
everything a human can in laying out pages.

TeX can too optimize page sequences! One does have to be rather clever, of 
course -- and TeX's documentation is, only slightly unjustly, renowned for 
its perversity -- but in a former job, I got TeX to automatically lengthen 
or shorten spreads in order to minimize the number of widows and orphans 
in long chapters of text. I rather doubt XSL-FO would allow that, either 
....

And here's another: Can an XSL-FO formatter place floats alternately on 
the tops and bottoms of pages? That is, given a spread with one float on 
each page, most layout artists prefer the floats to align diagonally, one 
at the top and one at the bottom of the pages. Which goes where depends on 
where the floats were cited. If the first float was cited on a previous 
spread, then it goes at the top of the left-hand page; otherwise, it goes 
on the bottom.

Note that I refer to TeX, not LaTeX. These sorts of machinations are much 
more difficult on top of LaTeX.