[boost] Re: Re: Re: Re: [pointer container] copyability

From: Thorsten Ottosen (nesotto_at_[hidden])
Date: 2005-04-26 18:15:29

"Peter Dimov" <pdimov_at_[hidden]> wrote in message 
news:099701c54ab2$8f8fb080$6401a8c0_at_pdimov2...
| Thorsten Ottosen wrote:

| > I think you have to explain why they are not different then.
|
| The burden of proof lies usually with the person making the statement. ;-)

no, the burden of proof lies on the person making the controversial statement; 
in this case you.

stuff like "value-based programming is not different from OO-programming" just 
seems weird to
me; we probably won't get anywhere before we can agree on how to define these 
two terms.

| The reference semantics vs value semantics axis is orthogonal to OO, in my
| opinion.
| The fact that in C++ you can't (efficiently) have polymorphism with
| value semantics doesn't mean that copying a value and copying a polymorphic
| object are conceptually or fundamentally different.
| A cloning pointer is a very good approximation of a polymorphic value. I
| don't see why you consider it conceptually different from a value.

because you had to put "polymorphic" in front of "value" to describe what it 
means;
polymorphic objects don't have value-based copy-semantics; you can't provide 
meaningful copy-constructor
and copy-assignment operators.

A "value object" implies something that behaves as an int; a "polymophic 
object" implies something that
needs to allocated dynamically and which has virtual functions.

trying to make a polymorphic object behave like a value object is confusing a 
best.

-Thorsten