Proposal: Private modules (general discussion)

[josevalim]

@imetallica

A. I like this idea, but with another name: @visible_to [MyApp, Foo, ...] . And if any module not in that list tries to use, import or whatever it will be a compilation error, much like what happens when you try to call a defp function outside the module you are defining it.

We can’t have compilation errors with A because it is best-effort. It would be jarring to have compilation fail only from to time or in a later optional pass. If you want errors, then you need the require mechanism and a separate namespace.

@imetallica

It breaks the semantics of the language. defp (an alias for defprivate) doesn’t allow access to functions outside the module, but defmodulep allows explicit visibility to some modules. Another naming is required.

That’s a good point and we can discuss other names. However, that would be too specific for now. So instead of worrying about the names themselves (such as scope/defmodulep), can you please share your thoughts on the proposal in considering the merits of the mechanisms instead, regardless of names? Thanks!