repos / handle-examples.hs.git

WeatherProvider.hs

 1{-# LANGUAGE DataKinds #-}
 2{-# LANGUAGE OverloadedStrings #-}
 3{-# LANGUAGE TypeOperators #-}
 4{-# LANGUAGE TypeApplications #-}
 5
 6module WeatherProvider where
 7
 8import Data.Vinyl.TypeLevel
 9import HandleRec
10import qualified WindProvider as W
11import qualified TemperatureProvider as T
12import QueryTypes
13
14data WeatherData = WeatherData { temperature :: T.Temperature, wind :: W.WindSpeed }
15
16-- We union the methods of providers and extend it with a common method.
17type Methods = '[ '("getWeatherData", (Location -> Day -> IO WeatherData))
18  ] ++ W.Methods ++ T.Methods
19
20type Handle = HandleRec Methods
21
22getWeatherData :: Handle -> Location -> Day -> IO WeatherData
23getWeatherData = getMethod @"getWeatherData"