Sharepoint XSLT Dynamic filtering - sharepoint

Question

I'm trying to create a dynamic row filter based on a variable. I have the following code:
<xsl:variable name="filter" select="contain(#Title, 'title1') or contain(#Title, 'title2')"/>
<xsl:variable name="Rows" select="/dsQueryResponse/Rows/Row[string($filter)]" />
This unfortunately doesn't seem to work and I end up with all rows. I'm guessing the filter doesn't actually get applied, since I can copy and paste the output of the $filter variable, copy and paste it in the Row[] and it works as expected.
Anyone tried to do this before?
In case you're wondering the filter variable is actually created using a template that splits a string like:
title1 - title2 - title3
and returns a string like:
contain(#Title, 'title1') or contain(#Title, 'title2') or contain(#Title, 'title3')
Any help would be greatly appreciated!

Answer 1

You can't do what you seem to be attempting here. An XPath expression is atomical, you can't save parts of it and re-use them (apart from that it is contains(), not contain()).
You need something like this:
<xsl:variable name="Rows" select="
/dsQueryResponse/Rows/Row[
contains(#Title, 'title1') or contains(#Title, 'title2')
]
" />
Your "filter" does not work because if $filter is a string, then it is a string, nothing else. It does not get a magical meaning just because it looks like XPath. ;-)
This
<xsl:variable name="Rows" select="/dsQueryResponse/Rows/Row[string($filter)]" />
evaluates to a non-empty string as the predicate. And any non-empty string evaluates to true, which makes the expression return every node there is.
If you want a dynamic filter based on an input string, then do this:
<xsl:variable name="filter" select="'|title1|title2|title3|'" />
<xsl:variable name="Rows" select="
/dsQueryResponse/Rows/Row[
contains(
$filter,
concat('|', #Title, '|')
)
]
" />
The use of delimiters also prevents "title11" from showing up if you look for "title1".
Make sure your filter always starts and ends with a delimiter, and use a delimiter that is reasonably unlikely to ever occur as a natural part of #Title. (For example, you could use 
. If your title cannot be multi-line this is pretty safe.)