XSLT: Test if node exists regardless if it's a child or grandchild of current node

I'm working on some xslt transformations and I've just found out that ther开发者_运维知识库e might or might not be an extra node between my current parent and it's clildren, depending on external factors. So now I have to change my xslt code in order to deal with both of these scenarios:

scenario 1:

<parent>
   <child/>
   <child/>
<parent>

scenario 2:

<parent>
   <nuisance>
      <child/>
      <child/>
   </nuisance>
<parent>

I have situations in which I test="parent/child" or otherwise use this format of accessing a parent/node.

I need something like test="parent/magic(* or none)/child"

They only way I know of that can solve this problem is to use:

<xsl:choose>
    <xsl:when test="parent/child">
       <!-- select="parent/child"-->            
    </xsl:when>

    <xsl:otherwise>
       <!-- select="parent/*/child"-->      
    </xsl:otherwise>
</xsl:choose>

But this will triple my code in size and will be a lot of manual labour...

Help much appreciated!

---

Why not simply select the union of the two?

<xsl:apply-templates select="parent/child|parent/*/child"/>

This will select the correct nodes in both cases.

---

I have situations in which I test="parent/child" or otherwise use this format of accessing a parent/node.

I need something like test="parent/magic(* or none)/child"

This expression may be faster:

parent/child or parent/*/child

than the expression:

parent/child|parent/*/child

Almost any XPath engine will immediately stop the evaluation at the first occurence of parent/child or at the first occurence of parent/someElement/child

On the other side, the second expression selects the union of all parent/child and parent/*/child elements and there may be many such elements.

Even worse is:

<xsl:apply-templates select="parent/child|parent/*/child"/>        

A test, as the original question needs, is very different from applying templates on all nodes that match this test. Just testing for a condition can be significantly more efficient. The OP hasn't indicated in any way that the test is in any way connected to applying templates.