Re: [Caml-list] Object Features

[Alain Frisch <alain@frisch.fr>]

On 11/30/2014 04:49 PM, Gerd Stolpmann wrote:
> What could in deed be useful is a more light-weight construction that
> layers objects, i.e. you define a new object around an existing one:

Indeed, being able to define an object by extending an existing one 
would be quite useful (perhaps overriding some methods, being understood 
that this doesn't affect late-bound calls from that object to itself).

I'd rather see that as a new kind of class expressions, say "of object 
<expr>", where <expr> could be an object expression (with a fixed type)
so that you could write:

  let new_object old_object =
    object
      inherit of object (old_object : t)

      method foo = ...

      method! bar = ...
    end

This would also allow to merge two existing objects into one.

If <expr> has type < m1:t1; ...; mn: tn >, "of object <expr>" would be 
equivalent to

   let o = <expr> in
   object
     method m1 = o # m1
     ...
     method mn = o # mn
   end



-- Alain