Memoist is an extraction of ActiveSupport::Memoizable.

Since June 2011 ActiveSupport::Memoizable has been deprecated. But I love it, and so I plan to keep it alive.

Just extend with the Memoist module

require 'memoist'
class Person
  extend Memoist
  
  def social_security
    decrypt_social_security
  end
  memoize :social_security
end

And person.social_security will only be calculated once.

You can even do it with a method that takes arguments.

class Person
  def taxes_due(income)
    income * 0.40
  end
  memoize :taxes_due
end

This will only be calculated once per value of income.

Everyone who contributed to it in the rails repository.

• Joshua Peek
• Tarmo Tänav
• Jeremy Kemper
• Eugene Pimenov
• Xavier Noria
• Niels Ganser
• Carl Lerche & Yehuda Katz
• jeem
• Jay Pignata
• Damien Mathieu
• José Valim