has_many through habtm alternatives?

In the following hypothetical scenario, I'd like to associate Books
and Clubs.

Class Club < ActiveRecord::Base
            has_many :memberships
            has_many :readers, :through => :memberships

            #DOES NOT WORK
            #has_many :books, :through => :readers

            #DOES NOT ADD find_in_collection METHODS
            #has_many :books, :finder_sql =>
            # %q{
            # select distinct books.*
            # from books
            # join memberships on books.reader_id
= memberships.reader_id
            # and memberships.club_id =
#{self.id}
            # order by books.read_at desc
            # }
end

Class Memberships < ActiveRecord::Base
            belongs_to :club
            belongs_to :reader
end

Class Reader < ActiveRecord::Base
            has_many :memberships
            has_many :books
end

Class Book < ActiveRecord::Base
            belongs_to :reader
end

If Memberships were simply a mapping table (clubs_readers) and class
Club has_and_belongs_to_many :readers, I still couldn't specify that
class Club has_many :books, :through => :readers because you can't
associate through habtm.

Unfortunately, associating books through readers in class Club does
not work because readers is associated through memberships.
Apparently, multiple levels of indirection is not supported.

If you use finder_sql, all the find_in_collection methods are not
added to the association proxy. Without which I won't be able to call
my_club.books.find(:all, :conditions => 'is_read = true') or to do
pagination for example.

Does anyone have any idea how I can create this association without
finder_sql and perhaps extending the association proxy?

Thanks!

Bump

gsterndale wrote:

In the following hypothetical scenario, I'd like to associate Books
and Clubs.

[...]

If Memberships were simply a mapping table (clubs_readers) and class
Club has_and_belongs_to_many :readers, I still couldn't specify that
class Club has_many :books, :through => :readers because you can't
associate through habtm.

Unfortunately, associating books through readers in class Club does
not work because readers is associated through memberships.
Apparently, multiple levels of indirection is not supported.

If you use finder_sql, all the find_in_collection methods are not
added to the association proxy. Without which I won't be able to call
my_club.books.find(:all, :conditions => 'is_read = true') or to do
pagination for example.

Does anyone have any idea how I can create this association without
finder_sql and perhaps extending the association proxy?

Thanks!

Your right, the multi-pass :through statements are not supported. It's
messy enough as it is with just a single through. I really don't have a
good answer, and I think the silence may be because no one else has come
up with one either. But this has been sitting here a while, and I
thought it would be polite to at least let you know I looked at it. My
only thought is to write a few functions in Club like 'read_books' or
'unread_books' and drop back to SQL under the covers, but that is not a
good solution, just a hack.

Thanks Starr. I appreciate the thought. I'll update this thread if I
find a solution. Thanks again.