From: Yukihiro Matsumoto <matz@...>
Date: 2009-11-15T01:14:49+09:00
Subject: Re: Surprising behavior when extending instances

Hi,

In message "Re: Surprising behavior when extending instances"
    on Sat, 14 Nov 2009 23:50:05 +0900, Jim Crossley <jim@crossleys.org> writes:

|This surprised me:
|
|  module English; def say; "yes"; end; end
|  module French; def say; "oui"; end; end
|  x = Object.new
|  x.extend English
|  x.say                 # "yes"
|  x.extend French
|  x.say                 # "oui"
|  x.extend English
|  x.say                 # "oui"
|
|What wrong assumptions am I making that this surprises me?  What is
|the more elegant "Ruby way" of alternating an object's behavior at
|runtime?

#extend (and #include) include a module only once.

							matz.