I have a folder that contains subfolders. Within each subfolder is a bunch

of XML files. I want to iterate over all the XML files in all the subfolders.
I tried the following and it doesn't work:

<xsl:for-each select="collection('folder/*?select=*.xml')">
     <xsl:message>
         Root element = <xsl:value-of select="name(/*)"/>
     </xsl:message>
</xsl:for-each>

Which XSLT processor do you use/target? What happens exactly when you
run that code and "it doesn't work"?

What is the correct way to do this?

If you want real iteration I would suggest to use xsl:iterate instead of
xsl:for-each.

But I suspect the problem is with the right argument for the
"collection" function. If you use Saxon 9 and

I think you should get all files in "folder" and subfolders. I am not
sure whether you want to exclude files directly in "folder".