"Macro" expansion

OK.....



1) Where exactly can I use macro expansion of the form @foo:bar@ ?

I know I can use it within params, but can I use it elsewhere? If so,
where? For instance the following would be very nice:

sidai/kdesupport.xml

<package name="kdesupport" xml-version="1">

..

<configure>
  <constraint>
    <dependency type="essential" name="qt" version-spec="== @param:QT_VERSION@"/>
  </constraint>
</configure>

2) Currently we can look up into certain tables eg.

<param name="PKG_BUILD_DIR">@package:ark-dirs:BUILD_DIR@</param>

or something similar. It would be Really Nice if we could do this for any
arbitrary table field, not just ark-dirs.



So, what I'd ideally like, combining these two mechanisms:

In kde-allpkgs:

<qt-version>
<table>
  <entry name="kde--2.1.1">qt--2.2.2</entry>
  ..
</table>

..
..

<configure>
  <constraint>
    <param name="QT_VERSION">@package:qt-version:kde--2.1.1</param>
    <dependency type="essential" name="qt" version-spec="== @param:QT_VERSION@"/>
  </constraint>
</configure>

What do you think?

Matt