From: Intransition <transfire@...>
Date: 2010-08-24T00:18:49+09:00
Subject: Your thoughts on #memo ?

Like to get some thoughts on the following technique for memoization:

  # Memoize a method.
  #
  #   class MemoExample
  #     attr_accessor :a
  #     def m
  #       memo{ @a }
  #     end
  #   end
  #
  #   ex = MemoExample.new
  #
  #   ex.a = 10
  #   ex.m  #=> 10
  #
  #   ex.a = 20
  #   ex.m  #=> 10
  #
  def memo(&block)
    key = eval('__method__', block)
    val = block.call
    singleton_class = (class << self; self; end)
    singleton_class.__send__(:define_method, key){ val }
    val
  end

Downside / upsides to the approach? Any suggestions for improvement?
Or is this just an altogether bad idea?