Re: [Qemu-devel] ARM QOM conversion / class hierarchy

[Paul Brook]

> Rather than key off an ID you could also just break
> implementation-specific functionality out into a set of interfaces you
> implement/override as part of the objects' initialization. Same ends, and
> still fits the model pretty nicely, assuming the functionality is all
> derivable from the common base-class.

I don't think that helps a great deal, and the implementation ends up much the 
same.

You're just replacing an explicit enumeration with an implicit set of 
subclasses.  The only reason I can see for that is if you want to build a 
deliberately crippled version of qemu, which seems a bit of a stretch. Of if 
you're trying to maintain something out of tree, in which case you deserve all 
the pain we can give you.

Note that you can't make the interface part of the CPUState object, as single 
inheritance prevents those having any state.  It has to be a separate object 
that the CPUState links to.

Paul