The newer portage has a dynamic sets system such as @installed, @world, @live-rebuild and @preserved-rebuild (although I don't trust the latter). I was having a discussion with someone about the python-updater utility that must be run when a point release of python is updated and that's when I thought, "It would be nice if that was a dynamic set". So instead of running python-updater which has to crawl site-packages for a list of packages to rebuild, it would already be in a dynamic set. Though admittedly, I don't yet know how these sets work internally, it does at lease *appear* to be a more efficient way of performing a python-update.
Is this feasible, implementable, or just a stupid idea? I would be willing to try help implement it (I know a little python) and submit a patch if someone would point me to how these sets actually work.
Steps to Reproduce:
As an example, you can already do something like this to rebuild all python modules built for python-2.5:
emerge -1 /usr/lib/python2.5/site-packages