Configuring Generators¶

Generators are configured in your project file (project1.pgn.yaml). Each generator is a Dhall program referenced by a URL.

Adding a Generator¶

Open your project1.pgn.yaml and add an entry under the artifacts key:

space: my_space
name: music_catalogue
version: 1.0.0

artifacts:
  hasql: https://raw.githubusercontent.com/pgenie-io/haskell-hasql.gen/v0.1.0/gen/Gen.dhall

The key (hasql in the example) is the name pGenie uses for the output directory under artifacts/. The value is a URL pointing to the generator's entry-point Dhall file.

You can add multiple generators:

artifacts:
  hasql: https://raw.githubusercontent.com/pgenie-io/haskell-hasql.gen/v0.1.0/gen/Gen.dhall
  my-custom-gen: https://example.com/my-gen/Gen.dhall

Each generator produces a separate subdirectory under artifacts/.

Pinning Generator Versions¶

Always reference a specific tagged version of a generator URL (e.g. /v0.1.0/ in the URL above) rather than a mutable branch like main. This ensures your generated code is reproducible.

After the first run, pGenie records the content hash of each generator in freeze1.pgn.yaml:

https://raw.githubusercontent.com/pgenie-io/haskell-hasql.gen/v0.1.0/gen/Gen.dhall: sha256:fcc51fe6ae2f774bcb13684b680aae1a9b827451c3f56c1ae2875f1e64fe78e5

Commit freeze1.pgn.yaml to version control. On subsequent runs, pGenie verifies that every downloaded generator matches its recorded hash, making generation fully reproducible across machines.

Upgrading a Generator¶

To upgrade to a new version:

Update the URL in project1.pgn.yaml to point to the new version tag.
Delete the corresponding line from freeze1.pgn.yaml (or delete the whole freeze file).
Run pgn generate. The new generator will be fetched and a new hash recorded in freeze1.pgn.yaml.

Available Generators¶

Generator	Language / Library	Repository
`haskell-hasql.gen`	Haskell (hasql)	pgenie-io/haskell-hasql.gen

See the Codegens reference for details on each generator.

Generator Configuration¶

Some generators accept optional configuration. The configuration schema is defined by the generator itself. Refer to the individual generator's documentation for details.

The hasql generator currently requires no additional configuration:

artifacts:
  hasql: https://raw.githubusercontent.com/pgenie-io/haskell-hasql.gen/v0.1.0/gen/Gen.dhall