> I find the biggest advantage of objects over records to be the same as 
> polymorphic variants over classic variants:
No surprise, the duality between sum types (normal variant) and record 
types (duality mean that they can encode
one another through a functional encoding) can be lifted to objects for 
records ans polymorphic variants for sum ...

In Ocaml, the polymorphic variant sare a bit too limited to have the 
full duality. To do it one would need the
type system to know that in (match t with `A -> ... | x -> ...) x can 
not use `A. Nervertheless, J. Garrigue modular evaluator
is a bery nice illustration of this (look at his web page for the paper).

The problem is to have tuples, records, objects and modules to be only 
one thing (and by the way require that variant always have exactly one 
argument),
so that you do not have to choose which approach you prefer ...


Cheers,

-- 
Christophe Raffalli
Universite de Savoie
Batiment Le Chablais, bureau 21
73376 Le Bourget-du-Lac Cedex

tel: (33) 4 79 75 81 03
fax: (33) 4 79 75 87 42
mail: Christophe.Raffalli@univ-savoie.fr
www: http://www.lama.univ-savoie.fr/~RAFFALLI
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