Work with hpack's top-level
fields in a Dhall
record with the following executables;
with dhall-hpack-cabal write the .cabal for a .dhall package description.
with dhall-hpack-dhall show the package description expression, with imports resolved.
with dhall-hpack-json show the package description as JSON.
with dhall-hpack-yaml show the package description as YAML.