xslt获取祖先文件夹路径

Question

有没有一种很好的方法来获取基础uri并获得该祖先的文件夹路径？

<!--xslt2.0-->
<xsl:message select="base-uri()" />

<!--out-->
<!--file:/D:/works/ancestor/parent/index.xml-->


<!--I want to read the ancestor file in the ancestor folder.-->
<!--I want to derive this from the value of the base-uri().-->
<xsl:message select="document('file:/D:/works/ancestor/ancestor.xml')" />

Regerds