lib/hamster/immutable.rb in hamster-0.3.3 vs lib/hamster/immutable.rb in hamster-0.3.4

@@ -1,7 +1,5 @@
-require 'forwardable'
-
 module Hamster
 
   module Immutable
 
     def self.included(klass)
@@ -12,38 +10,69 @@
     end
 
     module ClassMethods
 
       def new(*args)
-        super.freeze
+        super.immutable!
       end
 
+      def memoize(*names)
+        include MemoizeMethods unless include?(MemoizeMethods)
+        names.each do |name|
+          original_method = "__hamster_immutable_#{name}__"
+          alias_method original_method, name
+          class_eval <<-METHOD, __FILE__, __LINE__
+            def #{name}
+              if @__hamster_immutable_memory__.instance_variable_defined?(:@#{name})
+                @__hamster_immutable_memory__.instance_variable_get(:@#{name})
+              else
+                @__hamster_immutable_memory__.instance_variable_set(:@#{name}, #{original_method})
+              end
+            end
+          METHOD
+        end
+      end
+
     end
 
+    module MemoizeMethods
+
+      def immutable!
+        @__hamster_immutable_memory__ = Object.new
+        freeze
+      end
+
+    end
+
     module InstanceMethods
 
-      extend Forwardable
+      def immutable!
+        freeze
+      end
 
       def immutable?
         frozen?
       end
 
-      alias_method :__copy__, :dup
-      private :__copy__
+      alias_method :__hamster_immutable_dup__, :dup
+      private :__hamster_immutable_dup__
 
       def dup
         self
       end
-      def_delegator :self, :dup, :clone
 
+      def clone
+        self
+      end
+
       protected
 
       def transform_unless(condition, &block)
         condition ? self : transform(&block)
       end
 
       def transform(&block)
-        __copy__.tap { |copy| copy.instance_eval(&block) }.freeze
+        __hamster_immutable_dup__.tap { |copy| copy.instance_eval(&block) }.immutable!
       end
 
     end
 
   end