Krzysztof Czainski <1czajnik <at> gmail.com> writes:
I just wanted to add an example... I think Pimpl should have the following property:
a) struct X { int f(); private: int a_; };
b) struct X : public pimpl<X>::value_semantics { int f(); };
The user of class X should not be able to tell the difference between a) and b).
X x;
Now in this case the user can tell the difference. In b) he can do x.null(), but in a) he can't. So Pimpl changes the interface. And that's what I want to avoid. Pimpl or no Pimpl, the interface of X should stay the same.
1) I firmly believe that the insistence on no difference between a) an b) is misguided. You are applying a programming pattern/idiom and you reap the benefits of that applications. 2) That said I do see your desire to deny x.null() to the user. I'd be interested to know why you are not noticing/satisfied with the obvious solution struct X : pimpl<X>::value_semantics { ...} V.