From: Adam Gardner <adam.oddfellow@...>
Date: 2009-05-14T02:02:07+09:00
Subject: Re: Why Fixnum===Fixnum is false?

Joel VanderWerf wrote:
> Fixnum is not an instance of Fixnum. Compare:
> 
> ------------------------------------------------------------- Object#===
>       obj === other   => true or false
> 
>       From Ruby 1.8
> ------------------------------------------------------------------------
>       Case Equality---For class Object, effectively the same as calling
>       #==, but typically overridden by descendents to provide meaningful
>       semantics in case statements.
> 
> ------------------------------------------------------------- Module#===
>       mod === obj    => true or false
> 
>       From Ruby 1.8

Uh, I think you omitted the most important part of the documentation, to 
whit, what it actually says about Module#===:

------------------------------------------------------------- Module#===
     mod === obj    => true or false
------------------------------------------------------------------------
     Case Equality---Returns +true+ if _anObject_ is an instance of
     _mod_ or one of _mod_'s descendents. Of limited use for modules,
     but can be used in +case+ statements to classify objects by class.

(and incidentally, it is also important to know that the class 'Class' 
does not define it's own #=== method, and so inherits from Module, which 
is hinted at but not explicitly stated here)
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