Meta Programming!

gistfile1.rb

class Supplier < ActiveRecord::Base
  # delegate name, phone, description and contact if franchise is present

  %w( name phone description contact ).each do |attribute|
    define_method(attribute.to_sym) do
      if self.attributes[attribute].present?
        self.attributes[attribute]
      elsif franchise.present?
        franchise.send(attribute)
      else
        nil
      end
    end
  end

  # now I want a method which says
  # delegate_if_franchise(:name)
  # delegate_if_franchise(:phone)
  # delegate_if_franchise(:description)
  # delegate_if_franchise(:contact)

  # solved it like that:


  def self.delegate_if_franchise(*fields)
    fields.each do |field|
      define_method(field.to_sym) do
        if self.attributes[field.to_s].present?
          self.attributes[field.to_s]
        elsif franchise.present?
          franchise.send(field.to_s)
        else
          nil
        end
      end
    end
  end

  delegate_if_franchise :name, :phone, :contact, :description
end