Urabe Shyouhei wrote:
> Meinrad Recheis wrote:
>>> I don't think so. Nil is _the_ nil, one and only instance of NilClass.
>>> Duping it doesn't make sense to me.  And a dup method to return
>>> identical object is just strange.
>>>     
>> it makes sense to me, to implement dup on singleton objects like nil to
>> implement deep copying of arrays and hashes.
>>   
> 
> Marshal.load(Marshal.dump(obj)) and you get a deep copy of obj.  This is
> a well known idiom.  Any other chances for you to need a dup of nil?
> 

Marshal.load(Marshal.dump(obj)) is far more expensive than a well-crafted #dup
method and less semantically controllable.

Kurt Stephens