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Re: Deepcopying One container [message #23599 is a reply to message #23596]

Tue, 03 November 2009 19:45

mirek
Messages: 13984
Registered: November 2005

Ultimate Member

dolik.rce wrote on Tue, 03 November 2009 08:21

luzr wrote on Mon, 02 November 2009 11:14

Surprisingly, yes, we can provide polymorphic copies - by overloading DeepCopyNew.

That can be simplified by using PolyDeepCopyNew, using virtual
Copy method.

In reality, I have never really used polymorphic deep copy, it looks a little bit tricky to me. What is your usage scenario?

Mirek

PolyDeepCopyNew works like a charm! Thank you very much Mirek, the solution was trully genial in its simplicity.

Just for future reference, the solution is something like this:

#include <Core/Core.h>
using namespace Upp;

class A: public PolyDeepCopyNew<A>{
public:
	virtual void DoSmthng(){Cout()<<"I'm A.\n";};
	virtual A* Copy()const{return new A;}
};
class B:public A{
public: 
	virtual void DoSmthng(){Cout()<<"I'm B.\n";};
	virtual B* Copy()const{return new B;}
};

CONSOLE_APP_MAIN{
	One<A> a=new A;
	One<A> b=new B;
	One<A> c;
	
	c<<=a;
	c->DoSmthng();
	
	c<<=b;
	c->DoSmthng();
}

Honza

IMO, the example is a very little bit misleading - Copy should deepcopy some content...

Mirek

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