--- Robert Klemme <bob.news@[...].net>  wrote:
>  
>  "George Ogata" <g_ogata@[...].au> schrieb im
>  Newsbeitrag 
>  news:87zmvfx6u9.fsf@[...]..
>  > Eric Mahurin <eric_mahurin@[...].com> writes:
>  >
>  >> Anybody know how to generically copy (shallow like clone)
>  an
>  >> object into another object?  It would be nice to handle
>  the
>  >> case where the objects have a different class, but I would
>  at
>  >> least like to know how to do it when the classes are the
>  same.
>  >>
>  >> Here is an example of what I would like to do:
>  >>
>  >> dest = Object.new # or String.new if necessary
>  >> source = "hello world"
>  >> destid = dest.id
>  >>
>  >> source.clone_into(dest)
>  >>
>  >> dest             -> "hello world"
>  >> dest.id==destid  -> true
>  >> dest.class       -> String
>  >
>  > I hear that evil.rb has Object#become, which will do that
>  with some
>  > caveats.  Search "Object#become" in the list archives for
>  more info.
>  
>  If you just want to copy state you can do without evil magic
>  (although not 
>  working for builtins like String, Array, Fixnum etc.):
>  
>  class Object
>    def set_from(o)
>      o.instance_variables.each do |var|
>        instance_variable_set( var, o.instance_variable_get(
>  var ) )
>      end
>      self
>    end
>  end


Thanks for the pointers.  I downloaded evil.rb and tried
"become" (used dest.become(source) for the copy) and it did
exactly what I wanted.

I read a little more about become.  It looks like it might be
made standard in ruby at some point.  Will it have the above
functionality.  Or will it do something like what I think the
smalltalk "become" does - change all references to the
destination object to point to the source object.  I really
don't want the reference changes because a) it seems very
expensive (search the object space), and b) this would cause
the object id to change.

Anybody know when/if become will be made standard?


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