Existence Assertion for Named Scopes
May 11th, 2008
Forgive the overblown title, just leaving myself a quick note...
ActiveRecord::Base.metaclass.class_eval do
def named_scope_with_existence_assertion(*args)
named_scope_without_existence_assertion(*args)
define_method("#{scope_name = args.first}?"){self.class.send(scope_name).exists?(id)}
end
alias_method_chain :named_scope, :existence_assertion
end
Usage:
class Item < ActiveRecord::Base
named_scope :featured, :conditions => {:featured => true}
end
# obviously, this works...
Item.featured.find :all
# and now we get
Item.find(:first).featured? # does this instance satisfy the scope conditions?
Thanks for the idea, BB
