9. Modules and Packages

As a program grows, you can split it across files and bring names in with use. A package groups those files into a library or executable and records any outside code the project needs.

Visibility

Top-level declarations and members are private to their file unless marked pub:

pub struct User {
	pub let name: String
}

pub func load_user() -> User {
	User(name: "Ada")
}

Only a module's public surface can be imported elsewhere.

Imports

use can select names, alias them, import a module surface, or recursively import source submodules:

use package::models::{ User, load as load_user }
use package::models
use package::models::*
use self::child::{ value }
use super::shared::{ Thing }
use dependency::{ API }

Paths have distinct roots:

• package:: begins at the current package's source root
• self:: begins beside the importing module
• super:: begins at its parent module
• a dependency name begins at an external package's exported surface

use path imports that module's public surface. use path::* additionally walks source submodules recursively.

The core and standard libraries

Normal files implicitly receive the core library: primitives, arrays, strings, optional and result types, operators, iteration, Showable, memory roles, and host effects. A first line of // no-core disables it.

Modules under stdlib/ are explicit imports, such as:

use fs::{ File, Path }
use os::{ OS }
use task::{ channel, sleep }

Package manifests

talk new hello creates a package.tlk like this:

Package(
	name: "hello",
	version: "0.1.0",
	builds: [.bin(named: "main", from: "src/main.tlk")],
	dependencies: []
)

A package may build libraries and named binaries:

let builds: [PackageArtifact] = [
	.lib(from: "src/lib.tlk"),
	.bin(named: "server", from: "src/server.tlk")
]

Run a named binary with:

talk run --bin server

Dependencies and the lockfile

Dependencies may come from Git, a verified tar archive, or a local path:

let dependencies: [PackageDependency] = [
	.git(package: "widgets", url: "https://example.test/widgets.git", rev: "abc123"),
	.tar(package: "codec", url: "https://example.test/codec.tar.gz", sha256: "..."),
	.path(package: "shared", path: "../shared")
]

Use the package commands to manage resolution:

talk install
talk dependencies
talk update
talk update widgets

talk install resolves the graph into package.lock. talk update refreshes all or selected dependencies. --offline requires all needed sources to be available locally.

Package-aware commands

From anywhere inside a package, talk run, talk check, talk test, and the LSP locate the enclosing manifest. talk check with no filenames checks the package's declared targets and tests rather than every stray .tlk file under the directory.