Named scope with bang

I think it would be great if named scopes had a bang (!) variation
which applies to the current scope instead of returning a new scope.
This is very useful if you need to apply scopes conditionally like

topics = Topic.approved
topics.replied! if only_show_replied?
topics.scoped! :limit => limit if limit

I would love to get some feedback on this. Would you like to see the
same thing? You can find the patch here:


I haven't tested this, so I can't exactly give it the old +1, but I
expect it to come in handy in the future and it seems like a natural

- Trevor