From: ara.t.howard@...
Date: 2007-02-18T05:17:53+09:00
Subject: Re: Oppinions on RCR for dup on immutable classes

On Sun, 18 Feb 2007, Dean Wampler wrote:

>
> As someone else commented, perhaps the real issue is that
> 5.respond_to?(:dup) returns true yet 5.dup raises, so you have no way of
> knowing in advance that you shouldn't call dup.
>

i simply do not understand this line of thinking - every call to every object
always has that characteristic

   f.respond_to? :read  #=> true
   f.gets               # EOFError

   q.respond_to? :pop   #=> true
   q.pop(true)          #=> ThreadError if empty

to me this really seems like a dynamic vs static issue - i just don't see how
ruby can save you, regardless of the impl of dup, or any other method.  one
cannot avoid hanlding runtime exceptions in a dynamic language.  one cannot
know in advance whether it's ok to call something - even if the object
responds to it.

regards.

-a
-- 
we can deny everything, except that we have the possibility of being better.
simply reflect on that.
- the dalai lama