[xsl] Re: not simple (or simple? :-) xpath matching

[Dimitre Novatchev <dnovatchev@xxxxxxxxx>]

Jeni tennison wrote:
>
> Your example is made a little bit more complicated by the fact that
> you want the 'nearest' chapter if there isn't an exact match. For the
> nearest before, you want the last chapter whose @id is less than or
> equal to the $chapter parameter, which makes the select expression:
> 
>   part[@id = $part]/chapter[@id <= $chapter][last()]
> 
> For the nearest after, you want the first chapter whose @id is greater
> than or equal to the value of the $chapter parameter, so the select
> expression is:
> 
>   part[@id = $part]/chapter[@id >= $chapter][1]
> 

Hi Daniel,

I dont find the answer above satisfactory.

Here's a better solution.

What is actually needed is:

min(abs($chapter - @id))

over the nodeset /document/part[@id = $part]/chapter

This can be found very ellegantly using a common generic template finding a "generic
minimum" node from a nodeset.

You can read more about generic templates and template references at:

http://sources.redhat.com/ml/xsl-list/2001-05/msg00276.html

http://lists.fourthought.com/pipermail/exslt/2001-May/000169.html

http://dpawson.co.uk/xsl/generic.html


You can find several ellegant Xpath (sorry Jeni, not Javascript :)) ) expressions
defining the abs() function here:

http://www.vbxml.com/snippetcentral/main.asp?view=viewsnippet&lang=&id=v20010405003934

However, my favourite so far is one given by Sara ???

$num * (-($num < 0) + ($num > 0))


Hope this really helped.

Cheers,
Dimitre Novatchev.



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