From: Mike Stok <mike@...>
Date: 2006-03-23T11:59:46+09:00
Subject: Re: what on earth..


On 22-Mar-06, at 9:51 PM, Joe Van Dyk wrote:

> a = 5
> puts  Fixnum == a.class   # spits out true
>
> # spits out "Who knows what I am.  :-("
> case a.class
> when Fixnum
>   puts "I'm a fixnum!"
> else
>   puts "Who knows what I am.  :-("
> end
>
>
> What's going on here?

case doesn't use == you can do this:

a = 5

case a
when Fixnum
   puts "I'm a fixnum"
else
   puts "other"
end

and by coincidence (not)

ratdog:~/tmp mike$ irb
irb(main):001:0> a = 5
=> 5
irb(main):002:0> Fixnum === a
=> true

ratdog:~/tmp mike$ 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.


Hope this helps,

Mike

-- 

Mike Stok <mike@stok.ca>
http://www.stok.ca/~mike/

The "`Stok' disclaimers" apply.