Implement bubbling of events up the type hierarchy.

lib/eventful.rb

@@ -38,7 +38,7 @@ def add_observer(*args, &block)
 
   def on(event, &block)
     observer = add_observer do |*args|
-      type, data = args.first, [self] + args[1..-1]
+      type, data = args[1], [args[0]] + args[2..-1]
       if type == event
         block ||= observer.to_proc
         block.call(*data)
@@ -48,10 +48,25 @@ def on(event, &block)
 
   def fire(*args)
     return if defined?(@observer_state) and not @observer_state
+
+    receiver = (Hash === args.first) ? args.shift[:receiver] : self
+    args = [receiver] + args
+
     changed(true)
     notify_observers(*args)
     changed(true)
+
+    args[0] = {:receiver => receiver}
+    self.class.ancestors.each do |klass|
+      klass.fire(*args) if Eventful === klass
+    end
   end
 
+  def self.included(base)
+    base.extend(self)
+  end
+
+  extend(self)
+
 end
 

test/test_eventful.rb

@@ -1,5 +1,6 @@
 require "test/unit"
 require "eventful"
+require "set"
 
 class Foo
   include Eventful
@@ -14,6 +15,10 @@ def bump!(x = 1)
   end
 end
 
+class Bar
+  include Eventful
+end
+
 class TestEventful < Test::Unit::TestCase
   def test_named_events
     ayes, noes = 0, 0
@@ -44,4 +49,17 @@ def test_chaining
 
     assert_equal 3, f.count
   end
+
+  def test_bubbling
+    bar1, bar2 = Bar.new, Bar.new
+    list = []
+    Bar.on(:aye) { |r| list << r }
+    Eventful.on(:aye) { |r| list << r }
+    Eventful.on(:noe) { |r| list << r }
+
+    bar1.fire(:aye)
+    assert_equal  [bar1, bar1], list
+    bar2.fire(:noe)
+    assert_equal  [bar1, bar1, bar2], list
+  end
 end