From: Brian Candler <B.Candler@...>
Date: 2003-07-27T07:11:34+09:00
Subject: Re: How to rescue any exception in 1.8?

Unfortunately the on-line version of the Pickaxe book doesn't have the image
which shows the exception hierarchy. There are probably a zillion programs
for dumping this out, but here's another one anyway:

require 'timeout'

class ObjTree
  def initialize
    @children = Hash.new([])
    ObjectSpace.each_object(Class) do |c|
      @children[c.superclass] += [c]
    end
  end

  def dumptree(klass, level = 0)
    puts "  "*level + "" + klass.to_s
    @children[klass].sort {|x,y| x.to_s<=>y.to_s}.each do |c|
      dumptree(c, level+1)
    end
  end
end

ObjTree.new.dumptree(Exception)   # or try Object