From: Robert Klemme <shortcutter@...>
Date: 2006-12-05T02:40:04+09:00
Subject: Re: help, my  'case/when' code doesn't work

On 04.12.2006 18:33, cremes.devlist@mac.com wrote:
> I've been using ruby for several months now so imagine my surprise when I wrote something using the 'case' construct and I discovered that I didn't understand how to use it! What's worse is that even after looking through the Pickaxe and some code "in the wild" that uses 'case' I still don't see what I'm doing wrong.
> 
> Here's the code in question:
> 
> def case_test(obj)
>   print "testing via case... "
>   case obj.class

Make that "case obj" instead.

>   when Array
>     puts "obj is a #{obj.class}"
>   when String
>     puts "obj is a #{obj.class}"
>   else
>     puts "obj is unknown: #{obj.class}"
>   end
> end
> 
> def if_test(obj)
>   print "testing via if... "
>   klass = obj.class
>   if klass == Array
>     puts "obj is a #{klass}"
>   elsif klass == String
>     puts "obj is a #{klass}"
>   else
>     puts "obj is unknown: #{obj.class}"
>   end
> end
> 
> case_test(Array.new)
> if_test(Array.new)
> case_test(String.new)
> if_test(String.new)
> case_test(Hash.new)
> if_test(Hash.new)
> cremes$ ruby a.rb
> testing via case... obj is unknown: Array
> testing via if... obj is a Array
> testing via case... obj is unknown: String
> testing via if... obj is a String
> testing via case... obj is unknown: Hash
> testing via if... obj is unknown: Hash
> 
> What am I doing wrong here?
> 

	robert