[Mono-list] Re: Is Objective-C support possible?

Martin Coxall coxall@cream.org
18 Feb 2002 22:18:44 +0000

> Just to clarify. The CLR does NOT dissallow multiple inheritance. It 
> just doesn't provide explicit support for it. There is a big difference. 
> Eiffell for .Net has multiple inheritance. John Gough's book "Compiling 
> for the CLR" has a section on implementing MI on top of the CLR. to quote
> "The CLR does not provide facilities for the direct implementation of 
> multiple inheritance. In particular, the CLR mechanisms for virtual 
> method dispatch and object layout are inherently tied to an execution 
> model with single inheritance and multiple interfaces. Nevertheless, as 
> the Microsoft managed c++ compiler shows, it is possible to implement MI 
> all the same. The fundamental idea behind such an implementation is to 
> ignore the CLR facilities for method dispatch and instead layout the 
> v-table explicitly" he then goes on to discuss several possible ways of 
> implementing this.

To be honest, I'm not sure that's a clarification. How can code be
managed if it bypasses the CLR virtual execution system? And, what about
IL's explicit support of single inheritance?