richardtifelt

class Class
  def memoize(*methods)
    methods.each do |method_name|
      safe_method_name = method_name.to_s.gsub(/(\!|\?)/, '_')
      class_eval("
        alias :'#{safe_method_name}_without_memo' :'#{method_name}'
        def #{method_name}
          if defined?(@#{safe_method_name})
            @#{safe_method_name}