Re: [Caml-list] Why should I use .mli files?

[Edgar Friendly <thelema314@gmail.com>]

On 10/31/2012 11:12 AM, Gabriel Scherer wrote:
>> Maybe it's my over-exposure to C++ lately, but I see a clear semantic for
>> type re-declaration:
>> 1) It is only allowed to re-declare types from the auto-import of a module
>> signature
>> 2) abstract types can be re-declared arbitrarily
>> 3) private foo types can be re-declared to foo
>> Nothing else can be re-declared.
I missed one case:
4) any type can be re-declared as itself.
This uses up the one "re-declaration" that an auto-imported type is allowed.
> Why not. We even have a syntax for explicit type overriding: "type! u = int"!
> (But if you want to preserve backward-compatibility and still make the
> implicit inclusion of the interface in the implementation the default,
> you need to allow innocent-looking definitions to have a rebinding
> semantics.)
Yes, the backwards compatibility is key to my proposal; existing 
.ml+.mli files would re-declare everything, resulting in all types being 
as listed in the .ml file.
> I liked the idea of reusing the "with type ..." semantics instead of
> introducing a new feature, but if this proposal can get rid of the
> rather ad-hoc "module type" construct, you're trading one ad-hoc for
> another ad-hoc yet potentially simpler feature. I would be happy with
> such a langage feature.
I hope my solution is not only potentially simpler, but easier for 
people to use and more natural for people coming to OCaml from other 
languages where types are declared once.  It also allows us to sidestep 
the issue of type declarations and recursion, as it doesn't depend on 
any new syntax.

E.