From: ara.t.howard@...
Date: 2006-12-27T05:45:35+09:00
Subject: Re: Hash with two identical keys?

On Wed, 27 Dec 2006, Trans wrote:

>> From Facets' multiton.rb (which is primarily Floran Franks' work), I'm
> getting somthing that doesn't make any sense:
>
>        POOLS[self] ||= {}
>        p POOLS[self].class
>        p POOLS[self].keys
>
> Is outputing:
>
>  Hash
>  [[{:strip_comments=>false}], [{:strip_comments=>false}]]
>
> How can two identical keys be in a hash?
>
> T.

hi trans-

afaik multiton.rb is mine

   http://codeforpeople.com/lib/ruby/multiton/multiton-1.0.2/lib/multiton.rb

the logic behind POOLS is that objects are cached this way

   POOLS[ class_of_object ][ args_given_to_new ] = obj

in otherwords, contructing two objects with the same argument lists will
contruct only one object.  it's the argument lists which are used to determine
uniqueness.  alternatively uniqueness will be determined via the method
'multiton_id' if you're class has implimented that instance method or the
object in question responds to it otherwise.  so, in your case, you might use
something like

   hash.to_a.sort.hash

or something unique like that.  eg

   class MyClass
     include Multiton

     attr :multiton_id

     def initialize h = {}
       @multiton_id = h.to_a.sort.hash
       super
     end
   end

kind regards.

-a
-- 
if you find yourself slandering anybody, first imagine that your mouth is
filled with excrement.  it will break you of the habit quickly enough. - the
dalai lama