From: Paul Brannan <pbrannan@...>
Date: 2004-07-03T05:48:45+09:00
Subject: Re: define_method to add a Class method?

On Sat, Jul 03, 2004 at 04:53:26AM +0900, Sean O'Dell wrote:
> I'd stick with eval; it does the job.  Something like this should work
> just fine:

Using eval doesn't allow the method to be executed in the context in
which it was created, which is what define_method allows.  You can make
it work by assigning a proc to a variable and then calling that proc
from the eval'd code, but that's overkill, since define_method does the
job:

  class Foo
    s = class << self; self; end
    l = 42 # local variable
    s.class_eval do
      define_method(:foo) do
        puts "here: #{l}"
      end
    end
  end

  Foo.foo #=> here: 42

We first get the singleton class and assign it to s, then call
define_method for the singleton class (we could call define_method from
inside the class << self block, but then we wouldn't have access to
local variables).

Paul