Modules & Packages

Aria's module system is filesystem-independent — multiple files can contribute to the same module. Imports are concise and unambiguous.

Module Declaration

Every file declares which module it belongs to with mod:

// src/auth/login.aria
mod auth

fn login(creds: Credentials) -> Session ! AuthError {
    ...
}

// src/auth/register.aria
mod auth

fn register(info: UserInfo) -> User ! AuthError {
    ...
}

// Both files contribute to the same 'auth' module

Imports

// Import a module
use auth

// Import multiple modules
use net, json, time

// Import specific items
use auth.{login, register}

// Import alias — refer to the module by a different name
use crypto as c
c.sha256(data)

// Rename a specific import
use crypto.sha256 as sha

Visibility

Declarations are public by default within a module. Use pub to export symbols for access from other modules. The compiler enforces visibility — accessing a private symbol from another file produces an E0704 error.

Resolution Order

When you reference a name, Aria resolves it in this order:

  1. Tier 0 builtins — println, Option, Result, etc.
  2. Local modules — your project's mod declarations
  3. Dependencies — packages from aria.toml
  4. Tier 1 stdlib — io, net, json, etc.

Project Manifest (aria.toml)

[project]
name = "myapp"
version = "0.1.0"
aria = "0.1"
entry = "src/main.aria"

[deps]
http = "1.2"
postgres = "0.8"
redis = "1.0"

[dev-deps]
mock = "0.3"

Multi-File Projects

myapp/
├── aria.toml
├── src/
│   ├── main.aria          # mod main, entry point
│   ├── auth/
│   │   ├── login.aria     # mod auth
│   │   └── register.aria  # mod auth
│   ├── models/
│   │   ├── user.aria      # mod models
│   │   └── order.aria     # mod models
│   └── handlers/
│       ├── api.aria       # mod handlers
│       └── web.aria       # mod handlers
// src/main.aria
mod main
use auth, handlers

entry {
    auth.initialize()
    handlers.startServer(":8080")
}

Next Steps