From: "Iñaki Baz Castillo" <ibc@...>
Date: 2008-05-05T23:01:58+09:00
Subject: Recursive dup

Hi, it seems that "dup" method is not recursive, so if we do:
  obj_b = obj_a.dup
then all the attributes of obj_b will be a exact copy of attributes of
obj_a, and not references.

But if an attribute of obj_a is an object containing objects inside
then those will be referenced and not copied. This is:

--------------------------------
class A
	attr_accessor :att
end

class Obj
	attr_accessor :kk
end

obj = Obj.new
obj.kk = "KAKA1"
a=A.new
a.att=obj

a
=> #<A:0xb7bf6de8 @att=#<Obj:0xb7c0dcf0 @kk="KAKA1">>

b=a.dup
=> #<A:0xb7becd97 @att=#<Obj:0xb7c0dcf0 @kk="KAKA1">>

b.a.kk="KAKA2"

a
=> #<A:0xb7bf6de8 @att=#<Obj:0xb7c0dcf0 @kk="KAKA2">>
-----------------------------------------

So finally, an attribute of an attribute of "a" is been modified when
modifying "b".
I know that I should personalize "dup" method for class A, but is not
any other way? Does exist any automatic way of doing it?
I expect some method "dup_recursive" that looks for objects into
attributes recursively and clones them instead of reference.

Is there something as it?

Thanks a lot.


-- 
Iñaki Baz Castillo
<ibc@aliax.net>