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From: Michael Marcin (mmarcin_at_[hidden])
Date: 2007-11-03 18:13:45


Vladimir Batov wrote:
> Marc,
>
> Just uploaded v0.6 which supports building of two separate class
> hierarchies -- separately for interfaces and for implementations as
> described in GoF Pattern Bible for the Bridge pattern.
>
> The interface hierarchy is built as
>
> struct Base : public pimpl<Base>::pointer_semantics {...};
>
> struct Derived : public Base {...}
>
> etc.
>
> The implementation hierarchy is still hidden and is built as
>
> template<> struct pimpl<Base>::implementation {...};
>
> template<> struct pimpl<Derived>::implementation : public
> pimpl<Base>::implementation {...};
>
> etc.
>
> Marc, let me know if that looks right for your purpose as I myself have no
> use for deep inheritance trees to test them out.
>
> Best,
> Vladimir.
>
>> Marc,
>>
>> I have re-read the Bridge pattern in GoF Pattern Bible. Their example is
>> just what you describe in your example. I agree that having/supporting
>> two separate hierarchies is an elegant solution to a few problems. Let
>> me think how pimpl<> might support that.
>>

Out of curiosity in this and all other examples of this pimpl library
public inheritance is used. Isn't this an implemented in terms (spelled
private) of rather than an IS-A (spelled public) relationship?

I'm sure there is a technical reason I'm missing.

Thanks,

Michael Marcin


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