Hello.

> > Parametric class type definitions should be helpful.
> > We might need as many type parameters as (class) type definitions involved;
> > do you think this can be problematic, 
> > particularly in respect of type error messages?
> >   
> Only experiments can tell us. But I suspect that using a systematic 
> scheme for defining classes and relating them to each other should avoid 
> users to make too many errors that come from a misunderstanding of the 
> type system ('self escaping its scoope, or unified wit a closed type, 
> etc.), thus allowing "advanced" use of caml objects by non type systems 
> experts (including me).

Boilerplates that help us avoid typing errors...
That sounds nice. 

> I plan to do some reasonable scale "OOcaml" coding (in my spare time) 
> for some project. I will first see if I can use some systematic scheme 
> successfully before I try anything with camlp4. 

I also look for how I can minimize in a (hopefully) intuitive way 
Jacques's code, avoiding bizarre code duplication. 
Please let me know when you have good news. 

> That said, some of us 
> tend to think of everything only from within ocaml, and I know that some 
> day I should give a try to other systems, like Scala and its "traits".

I am sure you can enjoy exotic time if you try to exploit Scala's goodies :-)
In respect of the exact subject we have been discussing, Scala may be more adapted.

As far as I am concerned, fortunately(?), polymorphic variants and type inference 
and other many many goodies of OCaml 
keep me from turning to another language. 

Best,
Keiko