39 lines
1.3 KiB
Plaintext
39 lines
1.3 KiB
Plaintext
module Test.Main where
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import Prelude
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import Control.Alternative (guard, (<|>))
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import Control.Monad.Logic.Class (class MonadLogic, interleave)
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import Control.Monad.Logic.Trans (runSFKT)
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import Control.Monad.Reader.Class (class MonadReader)
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import Control.Monad.Reader.Trans (runReaderT, ask)
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import Control.Monad.State.Class (class MonadState)
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import Control.Monad.State.Trans (runStateT, put, get)
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import Data.Maybe (Maybe)
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import Data.Tuple (fst)
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import Data.Tuple.Nested(type (/\), (/\))
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test :: forall m. MonadState String m => MonadReader Int m => MonadLogic m => m (Int /\ String)
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test =
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do
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(yield 1 <|> yield 2) `interleave` (yield 3 <|> yield 4)
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where
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yield n = do
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offset <- ask
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oldState <- get
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put (show n)
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newState <- get
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pure ((offset+n) /\ (oldState <> " became " <> newState))
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order1 :: Maybe String
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order1 = show <$> (runReaderT (runSFKT (fst <$> runStateT (test >>= \(x /\ s) -> guard (x `mod` 2 == 1) >>= \_ -> pure (x /\ s)) "initial")) 11)
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order2 :: Maybe String
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order2 = show <$> fst <$> (runStateT (runReaderT (runSFKT (test >>= \(x /\ s) -> guard (x `mod` 2 == 1) >>= \_ -> pure (x /\ s))) 11) "initial")
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order3 :: Maybe String
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order3 = show <$> fst <$> (runStateT (runReaderT (runSFKT test) 0) "initial")
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main :: Maybe String
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main = order1
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