create a context with a Ruby object as its scope

lib/v8/util/weakcell.rb

@@ -0,0 +1,32 @@
+require 'weakref'
+module V8
+  module Util
+    module Weakcell
+      def weakcell(name, &block)
+        unless storage = instance_variable_get("@#{name}")
+          storage = instance_variable_set("@#{name}", Storage.new)
+        end
+        storage.access(&block)
+      end
+      class Storage
+        def access(&block)
+          if @ref
+            @ref.__getobj__
+          else
+            populate(block)
+          end
+        rescue RefError
+          populate(block)
+        end
+
+        private
+
+        def populate(block)
+          occupant = block.call()
+          @ref = WeakRef.new(occupant)
+          return occupant
+        end
+      end
+    end
+  end
+end