Private Modules and useless default

[bobot]

It is useful to hide all the modules except a small number because:

• it gives better control on what is accessible
• it allows to simulate pack by hiding all except the main module.

The default value of private modules is the empty set, so we can't say all except some. In #106, which have been reverted, the field was positive public_interfaces so the default set was all the modules.

Is the analysis correct?

[rgrinberg]

Yeah, the analysis is correct. I thought about another way of improving the default. Whenever the user writes a lib interface module, all the other modules should be marked as private by default. This would only improve the situation for (wrapped true) libraries but I think (wrapped false) is a lost cause anyway.

[rgrinberg]

Whatever concrete suggestions we go with btw, I do agree that we should flip the private/public default for dune 2.0

[bobot]

Whenever the user writes a lib interface module, all the other modules should be marked as private by default.

When an LIB_NAME.mli is given to the library or also when a LIB_NAME.ml is given? But I think an explicit choice would be simpler.

We could:

• add a public_modules field which is mutually exclusive with private_modules. They define the same thing.
• add a :all to private_modules

[emillon]

I think that we could do the following:

• define public_modules as an OSL field (with :standard meaning every module)
• define (private_modules x) as a shortcut for (public_modules :standard \ x)

[bobot]

@emillon I like the definition as a shortcut it simplifies the documentation.

[rgrinberg]

When an LIB_NAME.mli is given to the library or also when a LIB_NAME.ml is given? But I think an explicit choice would be simpler.

Either one is considered as providing a lib interface module.

Okay so I think @emillon's suggestion is best. Just to clarify, the two fields will be mutually exclusive, right?

For dune 2.0, we can change the value of :standard to be just the name of lib interface module so that the default is more conservative. There's no need to touch the default for (wrapped false).

[emillon]

Just to clarify, the two fields will be mutually exclusive, right?

Yes!