From: ts <decoux@...>
Date: 2002-09-08T23:05:50+09:00
Subject: Re: Ruby aesthetics

>>>>> "P" == Paul Brannan <pbrannan@atdesk.com> writes:

P> 4) I'm not sure how well this maps to C.  It should work, but it may not
P>    be the best solution.

 Yes, not the best

 Take this :

P> 1) Each class has a Hash which maps object id to a table of private
P>    instance variables.

 Change it to

 1) Each object has a table which maps object id of private variables 
    to an Hash
 2) look how ruby store instance variables

 and you have your implementation

pigeon% cat b.rb
#!./ruby
class A
   def initialize
      @_m = [1,2]
   end
   def a
      p "m = #{@_m.inspect}, n = #{@_n.inspect}"
   end
end

class B < A
   def initialize
      @_m = [2,4]
      @_n = 6
      super
   end
   def a
      p "m = #{@_m.inspect}, n = #{@_n.inspect}"
      super
   end
   def b
      remove_private_variable("@_n")
   end
end

  
b = B.new
c = Marshal.load(Marshal.dump(b))
c.instance_eval do
   p "m = #{@_m.inspect}"
   a
end
p c.private_variables(A)
p c.private_variables(B)
c.b
p c.private_variables(B)
pigeon% 

pigeon% b.rb
"m = nil"
"m = [2, 4], n = 6"
"m = [1, 2], n = nil"
["@_m"]
["@_m", "@_n"]
["@_m"]
pigeon% 


Guy Decoux