build permutation map

ladder.cabal

@@ -28,6 +28,7 @@ library
       Data.AssocMap
       Graph
       Lib
+      PermutationMap
   other-modules:
       Paths_ladder
   autogen-modules:

src/Data/AssocMap.hs

@@ -15,6 +15,7 @@ import Data.Maybe (fromMaybe, isJust)
 import Prelude hiding (lookup)
 
 newtype AssocMap k v = AssocMap [(k, v)]
+  deriving (Show)
 
 empty :: AssocMap k v
 empty = AssocMap []

src/PermutationMap.hs

@@ -0,0 +1,51 @@
+module PermutationMap
+  ( PermutationMap,
+    empty,
+    member,
+    alter,
+    delete,
+    insert,
+    lookup,
+    findWithDefault,
+    createPermutationMap,
+  )
+where
+
+import qualified Data.AssocMap as M
+import Data.List (nub, sort)
+import Data.Maybe (fromMaybe)
+import Prelude hiding (lookup)
+
+type PermutationMap = M.AssocMap String [String]
+
+empty :: PermutationMap
+empty = M.empty
+
+member :: String -> PermutationMap -> Bool
+member key = M.member (sort key)
+
+alter :: (Maybe [String] -> Maybe [String]) -> String -> PermutationMap -> PermutationMap
+alter f key = M.alter f (sort key)
+
+delete :: String -> PermutationMap -> PermutationMap
+delete key = M.delete (sort key)
+
+insert :: String -> [String] -> PermutationMap -> PermutationMap
+insert key = M.insert (sort key)
+
+lookup :: String -> PermutationMap -> Maybe [String]
+lookup key = M.lookup (sort key)
+
+findWithDefault :: [String] -> String -> PermutationMap -> [String]
+findWithDefault defaultValue key pmap = fromMaybe defaultValue (PermutationMap.lookup key pmap)
+
+createPermutationMap :: [String] -> PermutationMap
+createPermutationMap = aux empty
+  where
+    aux permMap [] = permMap
+    aux permMap (x : xs) = aux (insertPermutation x permMap) xs
+
+    insertPermutation word = alter (insertList word) word
+
+    insertList word Nothing = Just [word]
+    insertList word (Just xs) = Just $ nub (word : xs)