Replace O(n²) nub with O(n) HashSet-based deduplication

Add Hashable instance to JsonSchemaTree via DeriveAnyClass, rewrite
uniq in SequenceUtils to use a HashSet fold that preserves insertion
order. Remove accidentally committed opl.csv.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: danslapman

opl.csv

@@ -1,3 +1,4 @@
+{-# LANGUAGE DeriveAnyClass #-}
 {-# LANGUAGE DeriveGeneric #-}
 {-# LANGUAGE ImportQualifiedPost #-}
 {-# LANGUAGE LambdaCase #-}
@@ -36,7 +37,7 @@ type JsonPath = Seq JsonPathElement
 data JsonSchemaTree
   = PathNode JsonPathElement (Seq JsonSchemaTree)
   | PathEnd
-  deriving (Eq, Show, Typeable)
+  deriving (Eq, Show, Typeable, Generic, Hashable)
 
 type JsonSchema = Seq JsonSchemaTree
 

src/Schema.hs

@@ -1,16 +1,21 @@
 module SequenceUtils where
 
-import Data.Foldable (find, toList)
-import qualified Data.List as L
+import Data.Foldable (find, foldl', toList)
+import Data.Hashable (Hashable)
+import qualified Data.HashSet as HS
 import qualified Data.Maybe as Mb (mapMaybe)
 import Data.Sequence
 import Prelude hiding (concat, elem, foldl, foldl', foldl1, mapM, null, (++))
 
 maybeNes :: Seq a -> Maybe (Seq a)
 maybeNes = find (not . null) . Just
 
-uniq :: Eq a => Seq a -> Seq a
-uniq = fromList . L.nub . toList
+uniq :: (Hashable a, Eq a) => Seq a -> Seq a
+uniq = snd . foldl' step (HS.empty, empty)
+  where
+    step (seen, acc) x
+      | HS.member x seen = (seen, acc)
+      | otherwise        = (HS.insert x seen, acc |> x)
 
 mapMaybe :: (a -> Maybe b) -> Seq a -> Seq b
 mapMaybe _ Empty = empty

src/SequenceUtils.hs

@@ -14,7 +14,7 @@ testUniqEmptySequence :: Test
 testUniqEmptySequence = TestCase $ assertEqual "uniq empty sequence" (empty :: Seq Int) (uniq (empty :: Seq Int))
 
 testUniqNonEmptySequence :: Test
-testUniqNonEmptySequence = TestCase $ assertEqual "uniq non-empty sequence" (fromList [1, 2, 3]) (uniq $ fromList [1, 2, 2, 3])
+testUniqNonEmptySequence = TestCase $ assertEqual "uniq non-empty sequence" (fromList [1, 2, 3] :: Seq Int) (uniq $ fromList [1, 2, 2, 3])
 
 testMapMaybeEmptySequence :: Test
 testMapMaybeEmptySequence = TestCase $ assertEqual "mapMaybe empty sequence" (empty :: Seq Int) (mapMaybe (const Nothing) (empty :: Seq Int))