Package Management

Every non-trivial Flix project should have a flix.toml manifest. The manifest contains information about the project and its dependencies.

A minimal manifest is of the form:

name        = "hello-library"
description = "A simple library"
version     = "0.1.0"
flix        = "0.35.0"
license     = "Apache-2.0"
authors     = ["John Doe <>"]

Note: The flix field is not yet used, but it will be used in the future.

Adding Flix Dependencies

We can add dependencies on other Flix packages to the manifest:

"github:flix/museum"              = "1.4.0"
"github:magnus-madsen/helloworld" = "1.3.0"

Note: Flix requires version numbers to follow SemVer.

Adding Maven Dependencies

We can also add dependencies on Maven packages to the manifest:

"org.junit.jupiter:junit-jupiter-api" = "5.9.2"

Understanding Dependency Resolution

Flix dependency resolution works as follows:

  1. Flix reads flix.toml and computes the transitive set of Flix package dependencies.
  2. Flix downloads all of these Flix packages.
  3. Flix inspects each package for its Maven dependencies and downloads these.

We illustrate with an example. Assume we have a Flix package with:

"github:flix/museum"              = "1.4.0"

Running Flix produces:

Found `flix.toml'. Checking dependencies...
Resolving Flix dependencies...
  Downloading `flix/museum.toml` (v1.4.0)... OK.
  Downloading `flix/museum-entrance.toml` (v1.2.0)... OK.
  Downloading `flix/museum-giftshop.toml` (v1.1.0)... OK.
  Downloading `flix/museum-restaurant.toml` (v1.1.0)... OK.
  Downloading `flix/museum-clerk.toml` (v1.1.0)... OK.
  Cached `flix/museum-clerk.toml` (v1.1.0).
Downloading Flix dependencies...
  Downloading `flix/museum.fpkg` (v1.4.0)... OK.
  Downloading `flix/museum-entrance.fpkg` (v1.2.0)... OK.
  Downloading `flix/museum-giftshop.fpkg` (v1.1.0)... OK.
  Downloading `flix/museum-restaurant.fpkg` (v1.1.0)... OK.
  Downloading `flix/museum-clerk.fpkg` (v1.1.0)... OK.
  Cached `flix/museum-clerk.fpkg` (v1.1.0).
Resolving Maven dependencies...
  Adding `org.apache.commons:commons-lang3' (3.12.0).
  Running Maven dependency resolver.
Dependency resolution completed.

This happens because flix/museum has the following dependency tree:

  • flix/museum depends on:
    • flix/museum-entrance which depends on:
      • flix/museum-clerk
    • flix/museum-giftshop which depends on:
      • flix/museum-clerk
    • flix/museum-restaurant which depends on
      • org.apache.commons:commons-lang3

Publishing a Package on GitHub

Creating and publish a package on GitHub is straightforward:

  1. Check that you have a flix.toml manifest (if not create one with init).
  2. Check that the version field in flix.toml is correct.
  3. Run check and test to ensure that everything looks alright.
  4. Run build-pkg. Check that the artifact directory is populated.
  5. Go to the repository on GitHub:
    1. Click "Releases".
    2. Click "Draft new release".
    3. Enter a tag of the form v1.2.3 (i.e. use SemVer).
    4. Upload the package.fpkg and flix.toml from the artifact directory.

Tip: See the Museum Project for an example of a package that has been published on GitHub.