memoize.rb in facets-2.5.0

- old
+ new

@@ -14,16 +14,17 @@
 #       "#{@a ^ 3 + 4}"
 #     end
 #     memoize :a
 #   end
 #
-#   t = T.new
+#   t = T.new(1)
 #   t.a.__id__ == t.a.__id__  #=> true
 #
 # == Authors
 #
-# * Trans
+# * trans
+# * rtb
 #
 # == Copying
 #
 # Copyright (c) 2005 Robert Feldt
 #
@@ -34,10 +35,12 @@
 #
 # This program is distributed in the hope that it will be useful, but WITHOUT
 # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 # FOR A PARTICULAR PURPOSE.
 
+#require 'facets/memoizer'
+
 #
 class Module
 
   # Directive for making your functions faster by trading
   # space for time. When you "memoize" a method/function
@@ -57,15 +60,14 @@
   #
   #   t = T.new
   #   t.a.__id__ == t.a.__id__  #=> true
   #
   def memoize(*meths)
-    @_MEMOIZE_CACHE ||= Hash.new
     meths.each do |meth|
-      mc = @_MEMOIZE_CACHE[meth] = Hash.new
       old = instance_method(meth)
       new = proc do |*args|
+        mc = ((@_MEMOIZE_CACHE ||= {})[meth] ||= {})
         if mc.has_key? args
           mc[args]
         else
           mc[args] = old.bind(self).call(*args)
         end
@@ -75,26 +77,21 @@
   end
 
 end
 
 # This allows memoize to work in main and instance scope too.
-#--
-# Would this be good to have? Will need to modify for instance level, if so.
-#++
-
 def memoize(*args)
   Object.memoize(*args)
 end
 
-#
-module Kernel
+module Kernel #:nodoc:
 
   # Object#cache is essentially like Module#memoize except
   # it can also be used on singleton/eigen methods.
   # OTOH, memoize's implementation is arguably better for it's
   # use of #bind instead of #alias. Eventually the two implmenations
-  # will be reconciled with a single implmentation.
-
+  # should be reconciled with a single implementation.
+  #
   def cache m = nil
     if m
       (Module === self ? self : (class << self; self; end)).module_eval <<-code
         alias_method '__#{ m }__', '#{ m }'
         def #{ m }(*__a__,&__b__)