ryanb/cancan — pull request #773 by timoschilling (2012-11-05 13:56:04+00:00)
Title: Proc as Rule condition

allow to use Proc (or other Objects that respond to call) as a Rule condition, so you can do slow stuff in it, with don't need to be execute each time the Ability Class will be instantiate.

```ruby
can :manage, Region, :_id.in => ->{ user.region.try(:self_and_child_ids) }
```

I know the tests are missing, but currently i only want to know, is the this a good or bad idee / way to that?