> Now the answer is very short: you cannot provide simultaneously (in
> the same mode)
> 1) backward compatibility
> 2) commutation of (non-optional) labels
> 3) labels as documentation (that is, anywhere you feel like putting them)

1) has never been a requirement from me as a user or from the Caml team.
Caml-light and ocaml are not compatible Ocaml had also incompatible
change not to speak about the difference between Caml (the old one) and
Caml-Light !

I really think 1) is a VERY VERY BAD idea ! OCaml is a reasearch
language that is also really usable. But I want it to progress toward an
always better language. So 1) is not a reasonable constraint.

The only questions are: 
  - How hard is to port your code ? 
  - Can it be done automatically ?

So if an improvement is worth it add it to OCaml regardless of backward
compatibility !

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

tél: (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