From: Daniel Schierbeck <daniel.schierbeck@...>
Date: 2006-05-12T19:14:58+09:00
Subject: Re: Newb question - object type tests?

Adam Bloom wrote:
> Hello all,
> 
> I feel like I definitely should know this, but how do you test the type 
> of an object? For example:
> 
> item = ["hello"]
> item.array?
>> true
> item = "hello"
> item.array?
>> false
> 
> extending that, how do I test the type of a class that I made?

Others have already shown you how to test the *class* of an object (note 
that in Ruby, the class isn't the same as the type).

If you want to be more Rubyish, try this:

   item = ["hello"]
   item.respond_to? :to_ary  => true
   item = "hello"
   item.respond_to? :to_str  => true

So if you're writing a method that requires a string, just do this:

   def foo(bar)
     str = bar.to_str
     str.split(...
   end

That way, all classes that consider themselves strings need only define 
a #to_str method. If they actually do define the same methods as String, 
#to_str can just return `self'; otherwise it can return a string 
representation.


Cheers,
Daniel