From: James Edward Gray II <james@...>
Date: 2006-01-26T23:46:18+09:00
Subject: Re: Rethinking Memoization

On Jan 26, 2006, at 7:08 AM, Robert Klemme wrote:

> class SillySomething
>   extend Memoizable
>
>   def initialize()
>     @a,@b,@c = A.new, B.new, C.new
>     # or other initialization
>   end
>
>   def calculate_foo(quirk, quark, quork)
>      x = @a.foo(quirk) + @b.doit(quark)
>      if x > 10
>         x += @c.doh(quork, @a)
>      else
>         x - 2
>      end
>      x
>   end
>
>   memoize :calculate_foo
> end

This example runs as written with the module discussed in this  
thread.  It requires multiple changes to work with the current  
memoize.rb library.

> If (i) I don't see the point in having several objects that do  
> exactly the
> same calculation - methods might even be class methods (i.e. singleton
> methods of the *single* class instance X).  So there is actually no  
> need
> for a cache that covers several instances.
>
> If (ii) you gain nothing by having a centralized cache because  
> you'll have
> to keep memoized values from different instances separate; in fact  
> you add
> a level of lookup (first object, then method and args - or do it in  
> one
> request with a larger key) and separate instance state from the  
> instance.
> IMHO that's inefficient, memory leaking and error prone.

I understand know.  You're just against this feature.  Fair enough.

Thanks for taking the time to explain it to me.

James Edward Gray II