Awesome
Rave
The base type of this library is Rave
, which is short for Reader
, Aff
,
Variant
. Combined, Rave
is a standard stack for PureScript application
development. It implements
ReaderT
and
Checked Exceptions.
Rave does not support
interpeters,
but it would be possible to have purescript-run
interpret into Rave
.
newtype Rave r v e = Rave (ReaderT r (ExceptV v Aff) e)
ReaderT
The ReaderT part allows you to pass configuration along to your application without having to do so manually, which tends to clutter your codebase.
type Config =
{ port :: Int
, host :: String
, tokenInfoUrl :: String
, elasticSearchUrl :: String
}
config :: Config
config =
{ port: 8080
, host: "localhost"
, tokenInfoUrl: "http://localhost:8081/tokeninfo"
, elasticSearchUrl: "http://localhost:9200"
}
With Rave
and partial records, this code can be rewritten as
config =
{ port: 8080
, host: "localhost"
, databaseString: "postgresql://postgres@localhost"
}
main = runRave (RProxy :: _ ()) config do
dbConnection <- openConnection
startServer $ { dbConnection: DbConnection, host: config.host, port: config.port }
openConnection :: forall r. Rave { databaseString :: String | r } () DbConnection
startServer :: forall r. Rave { port :: Int, host :: String, dbConnection :: String | r } () -> Aff ()
Variant (checked exceptions)
Java has given checked exceptions a bad reputation. In PureScript, they have a comparatively low cognitive and LoC overhead.
Aff (effect)
Aff is a good default effect monad for any application. You may hit a few corner
cases with JavaScript APIs having timing issues with privileges (e.g.
window.open
), but 99% of the cases, it should be fine.