[xsl] Problem accumulating values.

[Patricia Santana Cruz <patriciasc@xxxxxxxxxxxxx>]

Hello,

I am having problems accumulating a value that I need in my program. I
have really tried every tip or recommendation I read in several forums
from people who had a "similar" problem and asked in the #xml channel
too, but unfortunately nobody could help.

I think that examples are better for explaining problems, so I go
straight with it. My .XML file has the following structure (small real
example: http://pastebin.com/SD6fcCtU):

<year>
  <week>
    <day>
      <task>
        <details></details>
      </task>
      <task>
        <details></details>
      </task>
    </day>
    <day>
      <task>
        <details></details>
      </task>
    </day>
  </week>
  <week>
    <day>
      <task>
        <details></details>
      </task>
      <task>
        <details></details>
      </task>
    </day>
  </week>
</year>

Each of these nodes have different attributes. The ones that matter are
those regarding to 'task':
 -end: string with dayTime value.
 -start: string with dayTime value.
 -name: string.
 -client: string.

In my .XSLT file, I am calculating the duration of each task doing:
<xsl:variable name="duration" select="xs:dateTime(@end) -
xs:dateTime(@start)"/>

The _problem_ is, that I need to calculate at the end of each week, the
total duration time of all the tasks for that week (week = duration time
of task 1 + duration time of task 2 + duration time of task 3...). I
have tried using the sum() function in different ways but did not
worked. I also tried creating a new tag inside my 'task' node, but it
just does not work, sum() keeps on appending the values instead of
summing them.

This is how my .XSLT file looks like: http://pastebin.com/jLV2EHFa

and this is the result generated file: http://pastebin.com/dDpJVqLL

As you see, the results are appended and not summed, which is what I
need.

Could you please help me with this issue?. I really do not know what
else I can do.

Thank you in advance,
Patricia.

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