Re: [Caml-list] Width subtyping

[Dave Benjamin <dave@ramenlabs.com>]

Dario Teixeira wrote:
> Hi,
> 
>> There must be something that escapes me.... This seems to be an
>> example where ocaml objects really shine because of the structural
>> typing (i.e. an object is defined by the its structure):
> 
> You are right.  I was probably too fixated on the OOP way of doing this,
> translating record fields into object fields and the functions acting on
> records into object methods.  Your solution, where record fields become object
> methods and external functions act on objects that match a certain structure,
> does solve the inconveniences I mentioned before.  But objects are still
> a somewhat heavier solution, right?

Heavier in terms of efficiency, or syntax? If you mean the latter, I 
wonder if a camlp4 syntax extension might help ease the burden; perhaps 
something like:

   #{x=5; y=6}

could be translated to:

   object method x = 5 method y = 6 end

and then you could benefit from a lightweight syntax and still get the 
static type checking.

Dave