RE: [xsl] GUI layout mechanism in XSLT

[Wendell Piez <wapiez@xxxxxxxxxxxxxxxx>]

Ilya,

It's an interesting problem.

At 10:14 AM 1/6/2005, you wrote:
> Producing <tr>s and </tr>s seems to be the most problematic issue in
> the whole task, because here it's necessary in many cases to start a
> new <tr>, while a vgroup is processed, and _not to generate the
> closing tag_ of this <tr> during this vgroup processing, because some
> of the elements, which will be processed later, are likely to be
> placed in the same row. This seems to be simply impossible to do in a
> straightforward way with XSLT.

Correct, if you qualify further: "impossible to do in a straightforward way 
with  XSLT 1.0 in a single pass".

Often such tricky processes are dealt with more straightforwardly if you 
break the problem into two passes. A first pass performs heuristics: in 
your case it could count up all the relevant neighbors of each item to 
derive the "size" information you need for each cell. A near-identity 
transform could amend the input with the results of this analysis. Then a 
second transform could skip the analysis, simply building the output using 
standard grouping techniques for table-building based on the values 
provided by the first pass -- thus dealing with the "can't close the row 
yet" issue. Although grouping can be a pain in XSLT 1.0, it's well 
understood and documented, and disentangling it from the analytics would 
isolate the problem here.

(After you were done you might even discover it's possible to fold the two 
passes back into one. I haven't given the problem enough thought to see 
whether that would be easy or worthwhile.)

> Note 2. The colspan attribute is needed just to complete a row in the
> output table in case if the last element of this row must be placed
> not in the last column of the table. But this is not that important:
> another possibility would be to generate empty cells at the end of the
> row in this case.

In two passes you could do this the "clean" way.

Sorry not to be able to help with the analytics themselves. I'm having to 
limit my advice today to pointing a possible way forward....

Cheers,
Wendell


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Wendell Piez                            mailto:wapiez@xxxxxxxxxxxxxxxx
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