copy yourself ?

jan ziak ziakjan at host.sk
Fri May 23 01:31:47 UTC 2003


yes we can look at the problem from the point you described below. i was just 
waiting who will mention that viewpoint as the first.

On Fri, 23 May 2003 11:53:31 +1200 (NZST), Richard A. O'Keefe wrote
> "jan ziak" <ziakjan at host.sk> wrote:
> 	i would like to ask whether some squeaker has ever seen an
> 	object which is capable of copying itself.
> 
> Why is that an interesting question?  I have never seen a physical object
> that could add 1 to itself either.  Smalltalk objects are not, for 
> the most part, simulations of physical objects and there is no 
> reason why they should go out of their way to imitate the 
> limitations of physical objects.
> 
> 	the point is that i do not
> 	believe that any object could copy itself.
> 
> Von Neumann proved that it could.
> 

my viewpoint on the self-reproduction is somewhat different - look in the 
message in which i was writing about "intelligent glass".

> 	so why, in smalltalk, almost every object can copy itself when i
> 	send a message to it - it seems absurd to me.  doesn't it also
> 	to you?
> 
> Not in the least.  Smalltalk objects can copy themselves because it
> is *useful* for them to be able to copy themselves.  There isn't the
> slightest absurdity in being useful.  On the contrary, what is
> EXTREMELY absurd is beating Smalltalk over the head because it has
> computational objects rather than physical objects.
> 
> 	a second problem is that the copying process depends on
> 	particularities of situation in which someone or something
> 	want's to copy an object.  copying is context dependent.  so why
> 	has every object in smalltalk only one method for copying (well
> 	it has three types of copy-methods but the point is that the
> 	number and meaning of them fixed).
> 
> Neither the number nor the meaning of copying methods is fixed.
> Any method can be overridden, and copying methods very often are.
> If you want to add a new #copyImprecisely method to Object,
> there isn't anything at all in Smalltalk to stop you.
> 
> In short, the number and semantics of copying methods is whatever you
> want it to be.
> 
> 	wouldn't it be more rational to have objects capable of
> 	constructing copies of objects?
> 	
> Clumsier, yes.  More rational?  In what conceivable way?
> 
> One more time:
>     COMPUTATIONAL OBJECTS ARE NOT PHYSICAL OBJECTS
>     AND SHARE NEITHER THEIR STRENGTHS NOR THEIR LIMITATIONS.
>     It is irrational to blame them for being different.






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