[PhillyOnRails] Dynamic Methods

[Cassius Rosenthal <cassius@xmodulation.com>]

I'm sure I'm alone when I say that I'm stuck on the dynamic 
class/methods thing.  In Rails, I have a record that has an attribute 
which specifies extra features of that record.  I think it would be cool 
(and appropriate?) to have the record's class dynamically change based 
on the attribute.  So here's what I have (fictitious abstraction):

In 'controllers/vegetable_controller.rb' I call the action 'record', 
which finds the Vegetable, sees that it's a tuber, and so loads the 
'tuber' model:

class VegetableController < ApplicationController
model :vegetable
def record
 @vegetable=Vegetable.find(@params[:id])
 # @vegetable.kind => "tuber"
 require 'models/vegetables/'+@vegetable.kind+'.rb'
end
end

In 'models/vegetable.rb' I have the base Vegetable class:

class Vegetable < ActiveRecord::Base
def self.list_all
 find(:all, :order => "name ASC" )
end
end

In 'models/vegetables/tuber.rb' I extend this instance of vegetable with 
the extra tuberific methods:

class << @vegetable
def roots
 @roots=true
end
end

In 'views/vegetable/record.rxml' I try to call the extra tuber methods:

xml.works(:value=>"true") if @vegetable.roots

. . . but it never works, unless I put the 'roots' function in the 
original class Vegetable definition.  Oh, RoR gurus, what say you?  
Other than the fictitiousness of the example, any obvious wrong-doing?  
Did I get get it all backwardsidedown?

Thanks!
-Cassius
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