From: Doug Glidden <41mortimer@...>
Date: 2008-08-29T10:31:46+09:00
Subject: Re: Class ===

Patrick Doyle wrote:
>> Forgive me if I'm missing something obvious, but wouldn't it be a whole
>> lot more logical to do this?
>>
>> if x.is_a? Array
>>  ...
>> end
> yup... that makes good sense too.
> 
> This is a great night! :-)
> 
> --wpd

Even better, if its possible you'd want to use the method on a structure 
other than an array in the future, use 'respond-to?' instead.  So for 
instance, if you're protecting a call to 'each':

if x.respond_to? :each
  x.each do
    ...
  end
end

That way, it'll work not only with Arrays, but also with Lists and 
Hashes or any other Enumerable class (or any class that implements 
each).  So if you later on decide that it would make more sense to store 
your data in a List instead of an Array, if you use 'is_a?' you'll have 
to go through and change your code every time you do this check, but if 
you use 'respond_to?', you won't have to change a single line!

Of course, there are situations where 'is_a?' is necessary, but 
'respond_to?' is generally preferable, from what I've seen.
-- 
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