From: Hal Fulton <hal9000@...>
Date: 2006-03-23T15:06:55+09:00
Subject: Re: what on earth..

Timothy Bennett wrote:
> 
> On Mar 22, 2006, at 8:22 PM, Caleb Clausen wrote:
> 
>>
>> For the cases you give, it seems pretty straightforward, but what  
>> about this:
>>
>> Fixnum===Class #false
>> Class===Fixnum #true
>>
>> Should Class be considered a Fixnum just because Fixnum is a Class?
>>
> 
> Hm, at least that makes sense.  However, it's hard for me to think of  
> === as having direction (it doesn't look like it has direction, and  
> therefore it can be difficult to remember which direction it's  supposed 
> to go sometimes).

I drew some (a little) criticism for spending four pages
in _The Ruby Way_ covering the case statement.

I think it's powerful, and I think it's done the Right Way,
and shouldn't be changed.

But I also think there are some non-obvious quirks (such as
you describe).

It also bears remembering that === is not called on the item
being tested, but on each of the items tested against. So

   case x
     when a
       do_something
   end

means

   if a === x
     do_something
   end


HTH,
Hal