From: Brian Mitchell <binary42@...>
Date: 2005-10-31T15:54:02+09:00
Subject: Re: determining whether an object is an immediate?

On 10/29/05, Eric Mahurin <eric_mahurin@yahoo.com> wrote:
> This is be best I could come up with for determining whether an
> object is an immediate (Fixnum, Symbol, false, true, nil,
> others?):
>
> begin
>   obj.clone
>   # clone worked - not an immediate
> rescue TypeError
>   # clone failed - immediate
> end
>
> Anybody have a better way?  If the above is the best, seems
> like an Object#immediate? would be nice to have.
>

The clone test does not work. Reason? There are plenty of
non-immediate objects that won't clone like Float and Bignum
instances. One test you could use is the singleton class:

# Should raise a TypeError
class << :immediate_object; end

Of course immediate object could also be found missing from
ObjectSpace, but I would imagine that test to be very slow.

May I ask why you need to know the immediacy of an object?

Brian.