From: Gavin Sinclair <gsinclair@...>
Date: 2002-12-06T17:08:09+09:00
Subject: Re: Printing subclasses

From: "ted" <ted@php.net>

> Can Ruby print the subclasses of a given class?  Like the reverse of the
> example of Class#superclass in "Reflection, ObjectSace and Distributed
> Ruby" in pickaxe.

def subclasses(the_class)
  result = []
  ObjectSpace.each_object(Class) do |klass|
    result << klass if klass < the_class
  end
  result
end

p subclasses(Numeric)  # -> [Bignum, Float, Fixnum, Integer]

Now I am justified in asking something that has bothered me for a while.  Why
can't ObjectSpace return an array of all objects of a given class/module.

Then the whole method above would be written as:

  ObjectSpace.objects(Class).select { |klass| klass < the_class }

Makes sense to me.

Gavin