ActiveRecord OR

Let's say you were trying to implement a SOPA enforcement tool:

class Blog < ActiveRecord::Base
  has_one :author
  ...
  scope :infringing,         where("artist_mentions_count > 0")
  scope :main_competition,   where("competition_rank > 7")
  scope :generally_disliked, where("subjective_dislike_rating > 3")
  ...
end

This would let you write handy things like

to_blacklist = Blog.infringing.or.main_competition.or.generally_disliked
to_harass    = Blog.joins(:author).where('authors.name' => 'Julian')\
                                  .or.generally_disliked

Also, if you call or on a condition-less scope, it will be ignored:

Blog.scoped.or.where(:name => 'Julian')

This means you can start off the query with an or, in case you don't know the state of the scope.

The end.

Credits

Gem extracted from (i.e. mostly sponsored by) http://www.hfa3.org/

TODO

Dispite the name of the gem, I'll probably add not logic also. Seems like or and not are really all that's missing from AR scopes.