From: SASADA Koichi <ko1@...>
Date: 2013-10-04T09:28:54+09:00
Subject: [ruby-core:57648] Re: [ruby-trunk - Feature #8977] String#frozen that takes advantage of the deduping

(2013/10/04 9:14), nobu (Nobuyoshi Nakada) wrote:
> I don't think it needs a new method nor class.
> 
>   frozen_pool = Hash.new {|h, s| h[s.freeze] = s}
> 
>   3.times {
>     p frozen_pool["foo"].object_id
>   }

for `f' syntax, we prepare frozen string table. Let it name "FrozenTable".

This proposal String#frozen can be defined by:

  class String
    def frozen
      FrozenTable[frozen] ||= self.freeze # rb_fstring(self) in C level
    end
  end

The difference between hash table approach and rb_fstring() is GC.
Frozen strings returned by Strign#frozen are collected if frozen strings
are not marked. But hash table approach doesn't allow collecting.

-- 
// SASADA Koichi at atdot dot net