Internal Packages

Modules support internal packages, which are packages accessible only within the same module. External packages cannot access internal packages. This is ideal for sharing code internally while keeping it hidden from outside consumers, a common requirement for third-party libraries.

To define an internal package, simply name the package internal. Any sub-packages under it are also treated as internal and inaccessible from outside the module.

Example project structure:

project/
├─ foo/
│  ├─ internal/
│  │  └─ internal.jule
│  ├─ jule.mod
│  └─ foo.jule
├─ jule.mod
└─ main.jule

The foo package has its own module (foo/jule.mod), making foo the root of its module. The internal package under foo is internal to this module. All code within the foo module can access it. The main.jule file belongs to a different module (the project root module) and cannot access foo/internal directory, even though it can import the foo package itself.