wkjagt · September 29, 2015 17:45 · Sep 29, 2015 · Sep 29, 2015 · Sep 29, 2015 · Sep 29, 2015
diff --git a/ruby-memoize.md b/ruby-memoize.md
@@ -1,3 +1,6 @@
+`Memoize` memoizes function return values based on class name, method name, and arguments. This means that this only works for functions that use state / have side effects.
+
+
 ```rb
 module Memoize
   def memoize(definition)	

diff --git a/ruby-memoize.md b/ruby-memoize.md
@@ -13,7 +13,11 @@ module Memoize
     }
   end
 end
+```
 
+Usage
+
+```rb
 class A
   class B
     extend Memoize
@@ -29,7 +33,6 @@ end
 
 b = A::B.new
 
-
 p b.heavy_calculation(4, 20)
 # "calling the original"
 # 80

diff --git a/ruby-memoize.md b/ruby-memoize.md
@@ -18,10 +18,12 @@ class A
   class B
     extend Memoize
 
-    memoize def heavy_calculation(a, b)
+    def heavy_calculation(a, b)
       p "calling the original"
       a * b
     end
+
+    memoize :heavy_calculation
   end	
 end
 

diff --git a/ruby-memoize.md b/ruby-memoize.md
@@ -0,0 +1,39 @@
+```rb
+module Memoize
+  def memoize(definition)	
+    self.send(:alias_method, "__original_#{definition}", definition)
+
+    define_method definition, Proc.new { |*args|
+      @__memo ||= {}
+
+      key = "#{self.class.name}##{definition}/#{args.hash}"
+      return @__memo[key] if @__memo.key?(key)
+
+      @__memo[key] = send("__original_#{definition}", *args)
+    }
+  end
+end
+
+class A
+  class B
+    extend Memoize
+
+    memoize def heavy_calculation(a, b)
+      p "calling the original"
+      a * b
+    end
+  end	
+end
+
+b = A::B.new
+
+
+p b.heavy_calculation(4, 20)
+# "calling the original"
+# 80
+p b.heavy_calculation(4, 20)
+# 80
+p b.heavy_calculation(2, 20)
+# "calling the original"
+# 40
+```