define method when hitting method missing

lib/charlatan.rb

@@ -45,15 +45,18 @@ def respond_to_missing?(method_name, include_private)
 
     def method_missing(method_name, *args, &block)
       if __proxy_target__.respond_to?(method_name)
-        response = __proxy_target__.public_send(method_name, *args, &block)
-
-        if response.equal?(__proxy_target__)
-          self
-        elsif response.kind_of?(__proxy_kind__)
-          self.class.new(*[response]+__proxy_args__)
-        else
-          response
+        self.class.send(:define_method, method_name) do |*options, &my_block|
+          response = __proxy_target__.public_send(method_name, *options, &my_block)
+
+          if response.equal?(__proxy_target__)
+            self
+          elsif response.kind_of?(__proxy_kind__)
+            self.class.new(*[response]+__proxy_args__)
+          else
+            response
+          end
         end
+        send(method_name, *args, &block)
       else
         super
       end

spec/unit/charlatan_spec.rb

@@ -73,6 +73,14 @@ def initialize(other, extra, &block)
     expect(object.size).to be(3)
   end
 
+  it 'will define the method after hitting method_missing' do
+    charlatan1 = Class.new { include Charlatan.new(:arr) }
+    object = charlatan1.new([])
+    object.should_receive(:method_missing).once.and_call_original
+    object.size
+    object.size
+  end
+
   context 'when target kind is provided' do
     subject(:charlatan) { klass.new(other_class.new) }