Simple memoize method for Ruby now that ActiveSupport::Memoizable is deprecated. Memoizes per argument set, handles falsy values.

example.rb

def my_method(foo, bar)
  memoize(:my_method, foo, bar) do
    foo * bar
  end
end

memoize.rb

def memoize(name, *args)
  @memoizations ||= {}
  @memoizations[name] ||= {}
  if @memoizations[name].has_key?(args)
    @memoizations[name][args]
  else
    @memoizations[name][args] = yield
  end
end