On Mon, May 30, 2016 at 11:22 PM, Vladimir Batov < Vladimir.Batov@constrainttec.com> wrote:
On 2016-05-31 13:41, Emil Dotchevski wrote:
On Sun, May 29, 2016 at 10:47 PM, Vladimir Batov < ... Polymorphism -- the snippets I provided are sufficient, virtual function calls work just fine. For example, in the CPP file you could define do_something (see above declaration) like so:
void do_something( foo * p ) { p->do_something(); //virtual } ...
Indeed. You right... Once we take the methods out to be free-standing functions, there is nothing left of the interface/proxy class but shared_ptr<foo>... I have to admit it never occurred to me... :-) Not sure if I am ready to do things your way :-) but you are most certainly correct. Thank you.
Wow I must admit this surprises me, the resistance I usually get is much stronger. :) The problem from language design point of view is that in C++ the "dot syntax" can only be used with member functions, but member functions have access to the private data, which means that they must participate in the type definitions (encapsulation), which means they can't be called without the type being complete. The C++ solution to this problem is to use only abstract types with no data members in header files, but that has virtual function call overhead compared to the C-style approach. It would have been useful for C++ to allow the declaration of non-friend "member" functions outside of the type definition. This would require no change in syntax. Thanks, Emil