tuning the behaviour of the -u option?

[René J . V . Bertin]

Hi,

I often long for a possibility to uninstall part of the inactive versions of a 
port when I upgrade it, but not all. It's probably overkill to support a 
universal filter that could theoretically catch all possible selections of 
inactive versions to prune and not to prune. There is however one useful case 
that might not be so hard: keeping a port's previous version or (easier to 
implement and guarantee) the currently active version/variant.

Thoughts?

R.