Replace our Observer class with the Eventful gem.

Rakefile

@@ -7,6 +7,7 @@ require './lib/siren.rb'
 Hoe.new('siren', Siren::VERSION) do |p|
   # p.rubyforge_name = 'sirenx' # if different than lowercase project name
   p.developer('James Coglan', 'jcoglan@googlemail.com')
+  p.extra_deps = %w[treetop eventful]
 end
 
 task :tt do

lib/siren.rb

@@ -1,8 +1,9 @@
 require 'rubygems'
 require 'treetop'
+require 'eventful'
 
 %w[ json json_query json_query_nodes
-    walker parser node reference observer
+    walker parser node reference
 ].each do |path|
   require File.dirname(__FILE__) + '/siren/' + path
 end
@@ -27,7 +28,8 @@ def self.parse(string, &block)
 
     @json_parser.walk(result) do |holder, key, value|
       if Hash === value && value[REF_FIELD]
-        value = Reference.new(value) do |ref, root, symbols|
+        value = Reference.new(value)
+        value.on(:resolve) do |ref, root, symbols|
           holder[key] = ref.find(root, symbols, holder)
         end
       end

lib/siren/node.rb

@@ -6,9 +6,9 @@ def from_json(hash)
       hash.each do |key, value|
         object.instance_variable_set("@#{key}", value)
         if Reference === value
-          value.add_observer(Observer.new { |ref, root, symbols|
+          value.on(:resolve) do |ref, root, symbols|
             object.instance_variable_set("@#{key}", ref.find(root, symbols, object))
-          })
+          end
         end
       end
       object

lib/siren/reference.rb

@@ -1,9 +1,7 @@
-require 'observer'
-
 module Siren
   class Reference
 
-    include Observable
+    include Eventful
 
     def self.flush!
       @@cache = {}
@@ -13,16 +11,14 @@ def self.resolve!(root, symbols)
       @@cache.each { |id, ref| ref.resolve!(root, symbols) }
     end
 
-    def initialize(hash, &block)
+    def initialize(hash)
       @query = Siren.compile_query(hash[REF_FIELD])
       @@cache ||= {}
       @@cache[hash.__id__] = self
-      add_observer(Observer.new(&block)) if block_given?
     end
 
     def resolve!(root, symbols)
-      changed(true)
-      notify_observers(self, root, symbols)
+      fire(:resolve, root, symbols)
     end
 
     def find(root, symbols, current)