From: "cardboard42@..." <cardboard42@...>
Date: 2008-08-09T06:03:09+09:00
Subject: Re: Works in irb but not elsewhere

I think what's happening is that yield is calling the block passed to
the caller of instance_eval so method is being called on self in that
block's closure. Since it was executed at the top level that would be
Object. Object.method takes 1 parameter, thus causing the error you're
seeing. The reason the code I posted works because it takes the block
passed to create and passes it directly to instance_eval as it's
block. This means that method will be called on self in instance_eval,
where it is set to the object instance_eval is called on, in this case
the result of A.new.

Sorry if my explanation is hard to understand, but I'm positive this
is not a bug in ruby. instance_eval { yield } simply has very
different semantics from instance_eval &block.

Ken