repos / handle-examples.hs.git

commit

1703c53

parent

82dee90

author

Evgenii Akentev

date

2023-03-30 23:02:46 +0400 +04

[row-handle]: Fix build and use composite implementation for WeatherProvider

 1@@ -11,7 +11,7 @@ import qualified WindProvider
 2 import qualified TemperatureProvider
 3 import QueryTypes
 4 
 5-data WeatherData = WeatherData { temperature :: T.Temperature, wind :: W.WindSpeed }
 6+data WeatherData = WeatherData { temperature :: TemperatureProvider.Temperature, wind :: WindProvider.WindSpeed }
 7 
 8 -- We union the methods of providers and extend it with a common method.
 9 type Methods = ("getWeatherData" .== (Location -> Day -> IO WeatherData))
10@@ -23,5 +23,5 @@ type Handle = HandleRow Methods
11 getWeatherData :: Handle -> Location -> Day -> IO WeatherData
12 getWeatherData = getMethod @"getWeatherData"
13 
14-getWindData :: Handle -> Location -> Day -> IO W.WindSpeed
15+getWindData :: Handle -> Location -> Day -> IO WindProvider.WindSpeed
16 getWindData = getMethod @"getWindData"

 1@@ -1,4 +1,6 @@
 2+{-# LANGUAGE RecordWildCards #-}
 3 {-# LANGUAGE OverloadedLabels #-}
 4+
 5 module SuperWeatherProvider where
 6 
 7 import Data.Row
 8@@ -8,8 +10,11 @@ import qualified WindProvider
 9 import QueryTypes
10 
11 new :: WindProvider.Handle -> TemperatureProvider.Handle -> Handle
12-new wp tp = #getWeatherData .== getSuperWeatherData .+ wp .+ tp
13+new wp tp = #getWeatherData .== (getSuperWeatherData wp tp) .+ wp .+ tp
14 
15 -- | This is some concrete implementation `WeatherProvider` interface
16-getSuperWeatherData :: Location -> Day -> IO WeatherData
17-getSuperWeatherData _ _ = return $ WeatherData 30 10
18+getSuperWeatherData :: WindProvider.Handle -> TemperatureProvider.Handle -> Location -> Day -> IO WeatherData
19+getSuperWeatherData wp tp loc day = do
20+  temperature <- TemperatureProvider.getTemperatureData tp loc day
21+  wind <- WindProvider.getWindData wp loc day
22+  return $ WeatherData{..}