From: Frederick Cheung <frederick.cheung@...>
Date: 2007-12-23T23:40:03+09:00
Subject: module_eval differences between 1.8 & 1.9

Consider the following:

module Foo
end

def do_stuff_to_foo(&block)
   Foo.module_eval &block
end

In ruby 1.8 you can do something like this

do_stuff_to_foo {def greeting; 'hello'; end}
Foo.instance_methods #=> ['hello']

In ruby 1.9 however, no method is added to Foo, instead the method is  
added to whoever called do_stuff_to_foo:

do_stuff_to_foo {def greeting; 'hello'; end}
Foo.instance_methods #=> []
greeting #=> 'hello'

Of course if you do
Foo.module_eval {def greeting; 'hello'; end}
then the method is added to Foo on both 1.8 & 1.9

I had a look through http://eigenclass.org/hiki.rb?Changes+in+Ruby+1.9  
but I didn't see anything that seemed relevant.
Is this intended? Is there a way to write the do_stuff_to_foo method  
in ruby 1.9 ?

Thanks,

Fred