I'm new to XSLT, and although I think I've mastered the basics I am completely stuck with the following problem. Help would be much appreciated!

Consider the following XML:

<Document>
    <Class name="A">
        <Attr name="x" type="String"/>
        <Attr name="y" type="Integer"/>
        <Attr name="z" type="Double"/>
    </Class>
    <Class name="B">
        <Attr name="p" type="String"/>
        <Attr name="q" type="String"/>
    </Class>
    <Object type="A">
        <AttrValue value="string1"/>
        <AttrValue value="10"/>
        <AttrValue value="3.14"/>
    </Object>
    <Object type="A">
        <AttrValue value="string2"/>
        <AttrValue value="20"/>
        <AttrValue value="2.71"/>
    </Object>
    <Object type="B">
        <AttrValue value="string3"/>
        <AttrValue value="string4"/>
    </Object>
</Document>

The rule is that Class/Attr[x] is associated with Object/AttrValue[x].

What is the xpath expression that would give me a node list of all AttrValue/@value whose corresponding Attr/@type = 'String'. Ie. the results for the above example would be string1 | string2 | string3 | string4

Is this possible? Thanks for your time.

This not possible then?

I've achieved the desired result using a template, but if doesn't feel right.

Cheers.