From: Blackie <mudsweatandears@...>
Date: 2007-10-20T04:05:08+09:00
Subject: Puzzle...cleaner way to redefine a method?

Here's a puzzle. There must be a cleaner way to do this.

I would like to have users of this class be able to call "set_wrapper"
and define pre and post behavior on the "working" method. The only
simple way I've found is evaling a string the redefines "working".
Searching threads on instance and class_eval tends to turn up an oil
slick of arguments and misinformation. Help is apprecaited!

~~~~~~~~~~
class Thing
  def set_wrapper(string)
    eval(string)
  end

  def working
    yield
  end

  def main
    working do
      p 'test'
    end
  end
end

a = Thing.new

a.main

a.set_wrapper("def working; p 'pre'; yield; p 'post'; end")

a.main