[Zope] metal strangeness

[KevinL]

Ok, can someone suggest a better way of saying this:

<span omit-tag="" tal:define="skin here/getSkin ; locSkin
here/getLocationSkin ; nonavbar python:1">
<metal:block
use-macro="here/skins/${locSkin}/pagelayout/macros/${skin}">

According to my reading of the docs, either
use-macro="here/skins/?locSkin/pagelayout/macros/?skin", or the above,
should work.  Certainly, here/pagelayout/macros/?skin works, but if I
put a ?locSkin in the middle of the url, it complains about a list()
operation over a non-sequence.

By my reading of the specs, metal attributes should use the tales
syntax, and the tales syntax says the above (first) is valid, I think?

Any suggestions/help greatfully accepted ;)

KJL