From: Shin Nishiyama <shin@...>
Date: 2003-07-10T17:49:31+09:00
Subject: Re: Doing a "case" on class

Hi,

case does not use == but === when comparision, and 
irb(main):032:0> Fixnum == Fixnum
=> true
irb(main):033:0> Fixnum === Fixnum
=> false

because
$ ri Module#===
------------------------------------------------------------- Module#===
     mod === anObject -> 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.

so, you shuould code like

>   fred = 123
>
    case fred
>      when Fixnum
>          puts "Yippee!"
>
>      # when <various other types>
>
>      else
>          puts "I don't know what to do with #{fred.class}"
>   end


Shin Nishiyama