Flexibility without Dependency Injection

gistfile1.txt

class TaxCode
  GENERATORS = {
    :us => lambda { |id| "US-#{id}" },
    :br => lambda { |id| "#{id + 9}-BRA" },
  }

  def self.generate(code, id)
    gen = GENERATORS[code] || raise ArgumentError, "No generator for country #{code}"
    gen.call(id)
  end
end

class User

  attr_accessor :country_code
  attr_accessor :id

  def tax_code
    TaxCode.generate(country_code, id)
  end
end

This is really cool, thanks for sharing it!

To complete the loop of the context in which this gist was written, it is in response to this blog post http://kresimirbojcic.com/2011/11/19/dependency-injection-in-ruby.html