From: Henry Maddocks <hmaddocks@...>
Date: 2012-05-23T10:35:47+09:00
Subject: Re: Disginguishing object types


On 23/05/2012, at 3:03 AM, "Jan E." <lists@ruby-forum.com> wrote:

> Hi,
> 
> Jeremy W. wrote in post #1061681:
>> 
>> Probably the easiest way is:
>> http://ruby-doc.org/core-1.9.3/Object.html#method-i-kind_of-3F
>> 
>> You might also want to consider:
>> http://ruby-doc.org/core-1.9.3/Object.html#method-i-respond_to-3F
> 
> To explain this a bit: In Ruby you usually don't judge objects by their 
> "type" (class) but by the existance of certain methods. This is called 
> duck typing.
> 
> The idea behind this is that the *behaviour* of an object matters, not 
> so much the class. 

Also, where possible, don't check for an arbitrary method, check for a method you need or are about to call on the object in question. This will indicate more clearly why you care what type the objects are. 


> However, in your case it's probably best to explicitly check for the 
> Array class and the String class (or a subclass).

Unfortunately String and Array share a lot of method names. 

Henry