# File lib/thinking_sphinx/association.rb, line 40
    def self.children(klass, assoc, parent=nil)
      ref = klass.reflect_on_association(assoc)
      
      return [] if ref.nil?
      return [Association.new(parent, ref)] unless ref.options[:polymorphic]
      
      # association is polymorphic - create associations for each
      # non-polymorphic reflection.
      polymorphic_classes(ref).collect { |klass|
        Association.new parent, ::ActiveRecord::Reflection::AssociationReflection.new(
          ref.macro,
          "#{ref.name}_#{klass.name}".to_sym,
          casted_options(klass, ref),
          ref.active_record
        )
      }
    end