From: Trans <transfire@...>
Date: 2006-10-07T02:15:15+09:00
Subject: Re: nil being empty


Trans wrote:

> That's the best example I have yet seen. Thanks for that Ara. Yet
> there's still a problem. Your expecting a NoMethodError on nil, just
> like I said. That's the thing, there's no other possible issue involved
> here. Now I'll grant James' concern that it can make some bugs harder
> to track down, but if that's our primary concern then I suggest we get
> back to static typing.
>
> Consider further, that ANY EXTENSION WHATSOEVER can have the same
> effect. If someone's class X defines #geegee and I add #geegee  to
> String, one can no long expect String to raise a NoMethodError on
> #geegee. So I argue that the bad form is not in using nil.empty? BUt in
> expecting such an error, and not addressing it properly.
>
>   hash_of_lists = Hash.new{|h,k| h[k] = new_list}
>   raise AProperError unless hash_of_lists[:key]
>   hash_of_lists[:key] << 42 if hash_of_lists[:key].empty?

Oh, one more thing. The best way to address the issue raised by James
is to add  selector namespaces to Ruby.

T.