I have an rss feed of the format:

<rss>
<tvshow id="17279" day="1" start="600" end="720" duration="120">
  <description> show 1 is about.. </description>
</tvshow>
<tvshow id="17280" day="1" start="800" end="920" duration="120">
  <description> show 1 is about.. </description>
</tvshow>
<tvshow id="17283" day="1" start="1000" end="1120" duration="120">
  <description> show 1 is about.. </description>
</tvshow>
<tvshow id="17289" day="1" start="1500" end="1620" duration="120">
  <description> show 1 is about.. </description>
</tvshow>
<tvshow id="17281" day="2" start="600" end="720" duration="120">
  <description> show 1 is about.. </description>
</tvshow>
<tvshow id="17282" day="3" start="600" end="720" duration="120">
  <description> show 1 is about.. </description>
</tvshow>
</rss>

I am aiming to have my XSL to get the current Time (ie xslt2 currentTime).  I want to compare this time to see if it falls within the interval of each of the show on a specific day (ie day 1).  If it falls within that timeslot, then I want to grab the description tag.  However, if the currentTime is within 30 minutes of the next show, I want the description to update within that 30 minute interval.

I can't think out the proper way to do this in XSL.  I can store a currentTime and then take the difference of the currentTime and the start time, and then compare the minimums.  This is easy to say but how do I code this in xsl?

Can I do something a recursive look to find the minimum difference (ie current show?)

example:

<xsl:if test="min(currentTime-/rss/tvshow/@start)"/>
<xsl:value-of select="description"/>
</xsl:if>

I take it that XSL is a little unintuitive since its done via recursion, but how would i implement something like this? just doing a test on min -- does it go through all the elements and finds the minimum?