In message "[ruby-talk:00613] Re: Bug in Array#clone!"
    on 99/08/11, GOTO Kentaro <gotoken / math.sci.hokudai.ac.jp> writes:

|>I should explain this more in detail; I changed the documents like:
|>
|>    dup
|>           Returns a newly created array which has the same
|>           elements to the receiver. clone returns the complete
|>           copy of the original array including freeze status and
|>           instance variables. On the other hand, dup copies the
|>           array contents only.
|>
|>Or should I copy the instance variables for these classes, and leave
|>documents unchanged?
|
|The latter looks better. It may be easy to see that the defference
|between clone and dup is frozen-property only. 

Well, an object can contain information like:

  contents: e.g. string, array, hash, etc.
  instance variables
  freeze status
  taint status
  some other flags
  singleton methods

clone copies all of them.

What information should be copied by dup?  Any opinion?

                                                matz.