From: Christopher Dicely <cmdicely@...>
Date: 2008-02-10T07:25:42+09:00
Subject: Re: Identifying

On Feb 9, 2008 2:14 PM, Adam Akhtar <adamtemporary@gmail.com> wrote:
> Farrel Lifson wrote:
>
> > Use a case statement:
> >
> >   array.each do |x|
> >     case x
> >       when Array: do something
> >       when Integer: do something
> >     end
> >   end
>
> is
>
> when Array: do something
>
> a valid statement??

Yes. "when" uses the === method of the object given, and Array is a
constant instance of class Class, and Class#===(obj) (inherited from
Module) is equivalent to obj.kind_of?(self)

>
> is
>
> if x == Array
>
> also a valid statement??

x == Array is a *valid* statement, but it doesn't mean the same thing.

case x
  when Array: ...
end

is the same as:

if Array === x then ... end

not:

if x == Array then ... end

> i was expecting having to use something like x.is_a as Stefano said.

As is oft the case with Ruby, there is more than one way to do it.