From: Michael Schuerig <michael@...>
Date: 2009-05-16T04:55:04+09:00
Subject: Re: obj.attr(qualifier) = value -- possible?

Joel VanderWerf wrote:

> I'm pretty sure that's impossible -- there is no #() method, or #()=.
> But there is #[]=, and you can adapt your Proxy approach to use it:

That's a good suggestion, but unfortunately, it doesn't fit in my case. 
I'm trying to do this stuff in an extension module for a Rails has_many 
:through association. It looks roughly like this

class Role < ActiveRecord::Base
  validates_presence_of :type # actor, director, ...
end

class Movie < ActiveRecord::Base
  has_many :roles
  has_many :participants, :through => :roles do
    def as(role)
      self.scoped(...) # joins and conditions omitted
    end
  end
end

This allows me to write code like

movie.participants.as('actor')

On top of that, I'd like to be able to write

movie.participants.as('actor') = params[:movie][:actors]

and that's where I'm stuck.

Michael

-- 
Michael Schuerig
mailto:michael@schuerig.de
http://www.schuerig.de/michael/