Modules

Modules give declarations a stable namespace and make dependencies explicit. Each module is compiled after its dependencies, while only the entry module's top-level expressions are evaluated.

Example::Main imports a value owned by Example::Greeting:

module Example::Greeting (value greeting) {
  greeting = "Hello from a Jazz module".
}

module Example::Main {
  import Example::Greeting.

  greeting.
}

Run it with:

cabal run jazz -- --run --entry-module Example::Main \
  --module-root examples/modules/src

Expected output:

"Hello from a Jazz module"

An import can expose all public names, select particular names, or introduce a qualifier. Export lists distinguish values, types, constructors, and capabilities. A module can export declarations it owns, but cannot re-export an imported declaration.

Module names map to paths beneath ordered module roots. Resolution rejects an ambiguous match or dependency cycle rather than choosing one implicitly. See module resolution for exact path, import, export, and Prelude rules.