logict/test/Main.purs
2023-03-04 19:01:57 -08:00

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