Re: [Boost-users] pattern support for traversing inheritance chain

Subject: Re: [Boost-users] pattern support for traversing inheritance chain
From: Krzysztof Czainski (1czajnik_at_[hidden])
Date: 2012-11-07 18:17:11

2012/11/8 Brian Budge <brian.budge_at_[hidden]>

> Hi all -
>
> I have a case where I have a largeish inheritance hierarchy.  I will be
> calling an initialization function on all objects before using them in some
> fashion.
>
> Basically what I need to happen is when I call init() on a Foo the
> following would occur:
>
> void Foo::init() {
>     super::init();
>     // now with the knowledge that anything I inherited is set up, I can
> set myself up...
> }
>
> It is not necessary for every call to implement init, in which case the
> behavior should be that the call is propagated up the inheritance chain
> (which it is by default in C++).
>
> In order to make this work, I need to write different code for "super" in
> every class implementation, which is a bit error prone.  Even if I don't
> copy/paste, my brain might be on autopilot and type something further up
> the inheritance chain than it should be.  Alternatively, I could require
> that each class provides a typedef for super, but I'm still relying on
> myself to remember to call super's init function.
>
> Is there anything in boost that would support this kind of hierarchy
> traversal (semi-)automatically?  If there is not, are there suggestions for
> ways to implement this in a less error-prone fashion?
>
> Thanks,
>   Brian
>

I think the constructors in C++ work the way you want init() to work. You
probably use two-step initialization, don't you? Can you avoid it?

Regards,
Kris