Support block observer in IVar, ScheduledTask, Observable

Author: brainopia

lib/concurrent/ivar.rb

@@ -42,9 +42,14 @@ def initialize(value = NO_VALUE, opts = {})
     #
     # @param [Object] observer the object that will be notified of changes
     # @param [Symbol] func symbol naming the method to call when this `Observable` has changes`
-    def add_observer(observer, func = :update)
+    def add_observer(observer, func = :update, &block)
       direct_notification = false
 
+      if block
+        observer = block
+        func = :call
+      end
+
       mutex.synchronize do
         if event.set?
           direct_notification = true
@@ -54,7 +59,7 @@ def add_observer(observer, func = :update)
       end
 
       observer.send(func, Time.now, self.value, reason) if direct_notification
-      func
+      observer
     end
 
     def set(value)

lib/concurrent/observable.rb

@@ -5,8 +5,8 @@ module Concurrent
 
   module Observable
 
-    def add_observer(*args)
-      observers.add_observer(*args)
+    def add_observer(*args, &block)
+      observers.add_observer(*args, &block)
     end
 
     def delete_observer(*args)

lib/concurrent/scheduled_task.rb

@@ -51,9 +51,9 @@ def cancel
     end
     alias_method :stop, :cancel
 
-    def add_observer(*args)
+    def add_observer(*args, &block)
       if_state(:unscheduled, :pending, :in_progress) do
-        observers.add_observer(*args)
+        observers.add_observer(*args, &block)
       end
     end