From: "ara.t.howard" <ara.t.howard@...>
Date: 2007-10-23T02:44:45+09:00
Subject: Re: Conflicts between using respond_to? and extending Ruby


On Oct 22, 2007, at 11:26 AM, David A. Black wrote:

>
>> case obj
>>   when Array
>>     ...
>>
>> is safer and more accurate.  i think it really depends on the use  
>> case - i personally use both.
>
> It does indeed depend; they do totally different things.

not entirely - they both allowing pre-testing to see if code is going  
to work or explode...

> I was
> describing the differences, specifically in the context of duck typing
> (or alternatives to duck typing): respond_to? gives you information
> about an object at a given moment, and kind_of? tells you about its
> ancestry.

well sortof:

   OpenStruct.new.respond_to?(:foo)  #=> false

   OpenStruct.new.foo()              #=> nil

as i said, i think it's 100% situational and you really can't make  
blanket rules.

cheers.


a @ http://codeforpeople.com/
--
it is not enough to be compassionate.  you must act.
h.h. the 14th dalai lama