Le 19 mars 08 à 17:29, Christopher L Conway a écrit :

> In short, the Bridge Pattern is applicable when a client needs access
> to operations F, G which can be provided by a variety of underlying
> implementations X, Y, or Z. If the specific implementation isn't
> important, you create an interface B (a "bridge") with operations F
> and G, and write both the client and the implementations to the
> interface B. The client should then be able to access X, Y, or Z
> interchangeably, e.g., by taking the implementation as an argument at
> initialization.

You need existential types. They can be encoded in ocaml, see here [1]  
the abstract counter datatype that does just what you describe above.

Best,

Daniel

[1] http://caml.inria.fr/pub/ml-archives/caml-list/2004/01/52732867110697f55650778d883ae5e9.en.html