[Aptitude-devel] Search term for existence

[Daniel Burrows]

On Wed, Feb 04, 2009 at 12:12:20AM +0100, Martin Stjernholm <apt at stjernholm.org> was heard to say:
> The search patterns in aptitude are very powerful, but there is one
> thing I fail to express:
> 
> I want to match a package according to condition A, provided there
> exists some other package that match condition B. (To be useful, the
> two conditions A and B would incorporate a common variable.)

  I toyed around with this at the time I introduced binding constructs,
but I can't remember why I didn't.  Probalby I got distracted by
something else, or maybe I just couldn't come up with a use case.

> I'm not quite sure that isn't possible to accomplish using ?for and
> ?bind, but if so I can't get my head around how to do it.

  I'm pretty sure you can't -- there's no way to inject arbitrary
packages into the search once you're matching a particular package.

> If it's implemented, then maybe its dualistic counterpart, the
> universal quantifier, could be considered too for completeness:

  Well, of course you'd want the dual. :)

  Daniel