From: Jeff Mitchell <quixoticsycophant@...>
Date: 2004-07-07T17:04:27+09:00
Subject: Re: Class#=== has interesting results

--- Charles Comstock <cc1@cec.wustl.edu> wrote:
> Why does this happen?
> 
> class A
> end
> 
> A == A		#1 => true
> A === A		#2 => false
> 
> a = A.new
> 
> a === A		#3 => false
> a == A 		#4 => false
> A === a 	#5 => true
> A == a 		#6 => false
> 
> 1 makes sense, A is an A so therefor it should be true
> 3 and 4 make sense since instance of A is not A and does not match A
> 5 and 6 make sense in that A matches a, but A is not an a.
> 
> But 2 doesn't make any sense to me, why doesn't an A match another A? 
> Is this just something that slipped through or is there a specific 
> reason for this?

whatisit = case obj
	   when Array
	      "it's an array!"
	   when Hash
	      "it's a hash!"
	   when Septuagenarian
	      "it's a septuagenarian!"
	   end

$ ri 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.



		
__________________________________
Do you Yahoo!?
Yahoo! Mail - Helps protect you from nasty viruses.
http://promotions.yahoo.com/new_mail