[xsl] use-when

[Andriy Gerasika <andriy.gerasika@xxxxxxxxx>]

Hello,
I cannot figure out how to use use-when attribute, beyond standard 
"system-property('file-separator')" example.

My code is overflown w/ "conditional" templates like:

<xsl:template match="some-xpath1[$file-set='A']">
<xsl:template match="some-xpath2[$file-set='B']">
<xsl:template match="some-xpath3[$file-set='C']">

$file-set is declared as parameter, but it is not really a parameter, it 
is the same for all files converted in a set, other parameters vary for 
each file.

I think System.setProperty("file-set", "A") is not a good choice, 
because there can be many transforms running in the background.

How to properly rewrite above "pseudo" use-when to "true" use-when, i.e.:
<xsl:template match="some-xpath1" use-when="user-property('file-set')='A'">
p.s.
I use Saxon-9 HE

Thank You
Andriy Gerasika
http://www.gerixsoft.com