Matthew Fulmer wrote:
> On Fri, Feb 23, 2007 at 10:35:35PM -0800, Andreas Raab wrote:
>   
>> Early on I thought the same way (and this was why we started thinking 
>> down that road when Nathanael interned with us). However, in practice it 
>> seems like Traits are mostly being used as a thinly veiled version of MI 
>> with all the same problems. You have correctly pointed out that Java 
>> interfaces are "nothing but abstract virtual base classes in C++" - 
>> which coincidentally, was the only way that MI ever worked in C++, which 
>> itself has two dozen ways of doing MI wrong and exactly ONE to do it 
>> right (abstract virtual base classes). Java choose a stand on that and 
>> it worked (which is pretty impressive given that it was the first 
>> language that used interface to that extent). Traits seem to reintroduce 
>> a number of ways of using MI wrongly (at least that's the feeling that I 
>> get when I look at the practical example) and that's why I prefer 
>> interfaces.
>>     
>
> Forgive me, but I am not familiar with "All the problems
> Multiple Inheritance got wrong". I will be testing out how
> Multiple Inheritance works in Squeak, since I have made it my
> top priority to get ThingLab [1] working in a recent Squeak
> system. ThingLab adds multiple inheritance [2] and a constraint
> solver to Smalltalk, and both have at least a good theoretical
> reason to be there, but I cannot test the implementation yet,
> since such a change currently breaks squeak. Multiple
> Inheritance has at least a solid theory; I have not had much
> experience with an implementation.
>
> [1] http://wiki.squeak.org/squeak/607
>     Links to ThingLab papers and code.
>
> [2] http://www.2share.com/thinglab/ThingLab%20-%20Chapter%203.html
>     Chapter 3 of the ThingLab paper. Section 2 contains a
>     defense of ThingLab's multiple inheritance.
>
>   
There is a newer constraint solver package called *Cassovary, that 
Joshua Gargus ported to Squeak.
I have a changeset I can digg up if you are interested.

Karl
*