Memoizer wraps objects to provide cached method calls.
class X def initialize ; @tick = 0 ; end def tick; @tick + 1; end def memo; @memo ||= Memoizer.new(self) ; end end x = X.new x.tick #=> 1 x.memo.tick #=> 2 x.tick #=> 3 x.memo.tick #=> 2 x.tick #=> 4 x.memo.tick #=> 2
You can also use to cache collections of objects to gain code speed ups.
points = points.collect{|point| Memoizer.cache(point)}
After our algorithm has finished using points, we want to get rid of these Memoizer objects. That's easy:
points = points.collect{|point| point.__self__ }
Or if you prefer (it is ever so slightly safer):
points = points.collect{|point| Memoizer.uncache(point)}
def self; @self; end
# File lib/more/facets/memoizer.rb, line 55 def self.cache(object) new(object) end
# File lib/more/facets/memoizer.rb, line 41 def initialize(object) @self = object @cache = {} end
# File lib/more/facets/memoizer.rb, line 59 def self.uncache(cached_object) cached_object.instance_variable_get('@self') end
# File lib/more/facets/memoizer.rb, line 46 def __self__ ; @self ; end
Not thread-safe! Speed is important in caches… ;]
# File lib/more/facets/memoizer.rb, line 49 def method_missing(method_name, *args, &block) @cache[[method_name, args, block]] ||= @self.__send__(method_name, *args, &block) end