Add tests for the logic monad transformer

test/Main.purs

@@ -2,10 +2,41 @@ module Test.Main where
 
 import Prelude
 
-import Effect (Effect)
-import Effect.Class.Console (log)
+import Control.Alternative (guard, (<|>))
+import Control.Monad.Logic.Class (class MonadLogic, interleave)
+import Control.Monad.Logic.Trans (SFKT, 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.List (List(..), (:))
+import Data.Maybe (Maybe)
+import Data.Tuple (fst)
+import Data.Tuple.Nested(type (/\), (/\))
 
-main :: Effect Unit
-main = do
-  log "🍝"
-  log "You should add some tests."
+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))
+
+solutions :: forall a m. Monad m => SFKT m a -> m (List a)
+solutions m = runSFKT m ((<$>) <<< (:)) (pure Nil)
+
+order1 :: Maybe String
+order1 = show <$> (runReaderT (solutions (fst <$> runStateT (test >>= \(x /\ s) -> guard (x `mod` 2 == 1) >>= \_ -> pure (x /\ s)) "initial")) 11)
+
+order2 :: Maybe String
+order2 = show <$> fst <$> (runStateT (runReaderT (solutions (test >>= \(x /\ s) -> guard (x `mod` 2 == 1) >>= \_ -> pure (x /\ s))) 11) "initial")
+
+order3 :: Maybe String
+order3 = show <$> fst <$> (runStateT (runReaderT (solutions test) 0) "initial")
+
+main :: Maybe String
+main = order1