[xsl] Evaluating condition strings

[Martin Heiden <martin.heiden@xxxxxxxxxxxxx>]

Hi!

I've got a XML doc which contains a description of a final document. 
This XML doc uses tags that handle conditions:

<if condition="var1 = true or var2 < 5 and var3 = 'ok'">
 <then>
     text
 </then>
 <else>
    another text
 </else>
</if>

the variables are available in another XML doc:
<attributes>
 <variable name="var1">false</variable>
 <variable name="var2">4</variable>
 <variable name="var3">ok</variable>
</attributes>

I think I could evaluate the conditions by writing an extension for the 
xslt processor (I'm using Xalan-J) or parsing the conditions before the 
transformation process  (maybe with a dynamic language like groovy 
because the variables are not typed.).

Could it be done with pure XSLT? What approach would you recommend?

TIA

 Martin