55 lines
1.4 KiB
Haskell
55 lines
1.4 KiB
Haskell
{-# LANGUAGE GADTs #-}
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{-# LANGUAGE TypeApplications #-}
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{-# LANGUAGE FlexibleContexts #-}
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{-# LANGUAGE TypeOperators #-}
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{-# LANGUAGE DataKinds #-}
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{-# LANGUAGE PolyKinds #-}
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{-# LANGUAGE TemplateHaskell #-}
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{-# LANGUAGE LambdaCase #-}
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{-# LANGUAGE ScopedTypeVariables #-}
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import Polysemy
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import Test.Hspec
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-- kind must be :: (* -> *) -> * -> *
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data Console m a where
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PrintLine :: String -> Console m ()
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ReadLine :: Console m String
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makeSem ''Console
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-- printLine :: Member Console r => String -> Sem r ()
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-- readLine :: Member Console r => Sem r a
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-- run :: Sem '[] a -> a
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-- runM :: Sem '[Embed m] a -> m a
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-- embed :: Member (Embed m) r => m a -> Sem r a
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runConsoleIO :: Member (Embed IO) r => Sem (Console ': r) a -> Sem r a
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runConsoleIO = interpret $ \case
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PrintLine msg -> embed $ putStrLn msg
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ReadLine -> embed $ getLine
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runConsolePure :: String -> Sem (Console ': r) a -> Sem r a
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runConsolePure s = interpret $ \case
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PrintLine msg -> pure ()
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ReadLine -> pure s
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spec :: Spec
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spec = describe "program" $ do
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it "adds 2 numbers given by user" $ do
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let res = run . runConsolePure "7" $ program
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res `shouldBe` (7 + 7)
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program :: Member Console r => Sem r Int
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program = do
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printLine "Insert number 1"
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a <- readLine
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printLine "Insert number 2"
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b <- readLine
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pure $ read a + read b
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main :: IO ()
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main = execute >>= print
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where
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execute = runM . runConsoleIO $ program
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