From d037a77161f828baa30d07e9cb62ddf05c85450d Mon Sep 17 00:00:00 2001
From: Matt Hunzinger <matt@hunzinger.me>
Date: Wed, 28 Jan 2026 19:42:05 -0500
Subject: [PATCH 1/6] feat: new monadic Query design

---
 aztecs.cabal                            |   1 +
 bench/Bench.hs                          |  11 +-
 src/Aztecs/ECS.hs                       |  26 +-
 src/Aztecs/ECS/Component.hs             |   2 +-
 src/Aztecs/ECS/Observer.hs              |   2 +-
 src/Aztecs/ECS/Query.hs                 | 431 +++++++++---------------
 src/Aztecs/ECS/Query/Dynamic.hs         |   4 +-
 src/Aztecs/ECS/System.hs                |  36 +-
 src/Aztecs/ECS/System/Dynamic.hs        |   2 +-
 src/Aztecs/ECS/View.hs                  |   4 +-
 src/Aztecs/ECS/World/Archetype.hs       |   4 +-
 src/Aztecs/ECS/World/Archetypes.hs      |   2 +-
 src/Aztecs/ECS/World/Storage.hs         |   4 +-
 src/Aztecs/ECS/World/Storage/Dynamic.hs |   4 +-
 src/Aztecs/Hierarchy.hs                 |  38 ++-
 test/Main.hs                            |  67 ++--
 16 files changed, 263 insertions(+), 375 deletions(-)

diff --git a/aztecs.cabal b/aztecs.cabal
index a54b2246..6904de1a 100644
--- a/aztecs.cabal
+++ b/aztecs.cabal
@@ -66,6 +66,7 @@ library
         base >=4.2 && <5,
         containers >=0.6,
         mtl >=2,
+        free,
         vector >=0.12
 
 test-suite aztecs-test
diff --git a/bench/Bench.hs b/bench/Bench.hs
index 00d47579..6314d39a 100644
--- a/bench/Bench.hs
+++ b/bench/Bench.hs
@@ -3,6 +3,7 @@
 {-# LANGUAGE FlexibleInstances #-}
 {-# LANGUAGE GeneralizedNewtypeDeriving #-}
 {-# LANGUAGE MultiParamTypeClasses #-}
+{-# LANGUAGE RankNTypes #-}
 
 import Aztecs.ECS
 import qualified Aztecs.ECS.Query as Q
@@ -22,13 +23,15 @@ newtype Velocity = Velocity Int deriving (Show, Generic, NFData)
 
 instance (Monad m) => Component m Velocity
 
-move :: (Monad m) => Query m Position
-move = queryMapWith (\(Velocity v) (Position p) -> (Position $ p + v)) query
+move :: (Applicative f, Monad m) => Q.Query f m (f Position)
+move = do
+  vs <- Q.query
+  Q.queryMap $ \ps -> (\(Velocity v) (Position p) -> Position $ p + v) <$> vs <*> ps
 
-run :: Query Identity Position -> World Identity -> Vector Position
+run :: (forall f. (Applicative f) => Q.Query f Identity (f Position)) -> World Identity -> Vector Position
 run q = (\(a, _, _) -> a) . runIdentity . Q.runQuery q . entities
 
-runSys :: Query Identity Position -> World Identity -> Vector Position
+runSys :: (forall f. (Applicative f) => Q.Query f Identity (f Position)) -> World Identity -> Vector Position
 runSys q = fst . runIdentity . runAccess (system $ runQuery q)
 
 main :: IO ()
diff --git a/src/Aztecs/ECS.hs b/src/Aztecs/ECS.hs
index 4de10b2d..8524d3fe 100644
--- a/src/Aztecs/ECS.hs
+++ b/src/Aztecs/ECS.hs
@@ -59,19 +59,12 @@ module Aztecs.ECS
     MonoidDynamicBundle (..),
     Component (..),
     EntityID,
-    Query,
+    Query (..),
+    QueryStream (..),
+    entity,
     query,
-    queryMaybe,
     queryMap,
-    queryMapM,
-    queryMapWith,
-    queryMapWith_,
-    queryMapWithM,
     queryMapAccum,
-    queryMapAccumM,
-    queryMapWithAccum,
-    queryMapWithAccumM,
-    DynamicQueryF (..),
     QueryFilter,
     with,
     without,
@@ -102,20 +95,13 @@ import Aztecs.ECS.Observer
     observerGlobal,
   )
 import Aztecs.ECS.Query
-  ( DynamicQueryF (..),
-    Query,
+  ( Query (..),
     QueryFilter,
+    QueryStream (..),
+    entity,
     query,
     queryMap,
     queryMapAccum,
-    queryMapAccumM,
-    queryMapM,
-    queryMapWith,
-    queryMapWithAccum,
-    queryMapWithAccumM,
-    queryMapWithM,
-    queryMapWith_,
-    queryMaybe,
     with,
     without,
   )
diff --git a/src/Aztecs/ECS/Component.hs b/src/Aztecs/ECS/Component.hs
index 5039e0fe..ae6dcb36 100644
--- a/src/Aztecs/ECS/Component.hs
+++ b/src/Aztecs/ECS/Component.hs
@@ -21,7 +21,7 @@ import Aztecs.ECS.Component.Internal (ComponentID (..))
 import Aztecs.ECS.Entity
 import Aztecs.ECS.World.Storage
 import Data.Typeable
-import Data.Vector (Vector)
+import Data.Vector.Strict (Vector)
 
 -- | Component that can be stored in the `World`.
 class (Monad m, Typeable a, Storage a (StorageT a)) => Component m a where
diff --git a/src/Aztecs/ECS/Observer.hs b/src/Aztecs/ECS/Observer.hs
index dbbe63be..dd20072b 100644
--- a/src/Aztecs/ECS/Observer.hs
+++ b/src/Aztecs/ECS/Observer.hs
@@ -39,7 +39,7 @@ import Control.Monad.State
 import Data.Set (Set)
 import qualified Data.Set as Set
 import Data.Typeable
-import Data.Vector (Vector)
+import Data.Vector.Strict (Vector)
 
 -- | The kind of observer - either entity-specific or global.
 data ObserverKind m e
diff --git a/src/Aztecs/ECS/Query.hs b/src/Aztecs/ECS/Query.hs
index cc35da2a..8b65e038 100644
--- a/src/Aztecs/ECS/Query.hs
+++ b/src/Aztecs/ECS/Query.hs
@@ -3,8 +3,12 @@
 {-# LANGUAGE DeriveFunctor #-}
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE GADTs #-}
+{-# LANGUAGE GeneralizedNewtypeDeriving #-}
 {-# LANGUAGE InstanceSigs #-}
+{-# LANGUAGE LambdaCase #-}
 {-# LANGUAGE MultiParamTypeClasses #-}
+{-# LANGUAGE RankNTypes #-}
 {-# LANGUAGE ScopedTypeVariables #-}
 {-# LANGUAGE TupleSections #-}
 {-# LANGUAGE TypeApplications #-}
@@ -18,37 +22,24 @@
 -- Maintainer  : matt@hunzinger.me
 -- Stability   : provisional
 -- Portability : non-portable (GHC extensions)
---
 -- Query for matching entities.
 module Aztecs.ECS.Query
   ( -- * Queries
     Query (..),
-    DynamicQueryF (..),
 
     -- ** Operations
+    entity,
     query,
-    queryMaybe,
+    queryDyn,
     queryMap,
-    queryMap_,
-    queryMapM,
-    queryMapWith,
-    queryMapWith_,
-    queryMapWithM,
     queryMapAccum,
-    queryMapAccumM,
-    queryMapWithAccum,
-    queryMapWithAccumM,
 
     -- ** Running
+    runQuery',
     readQuery,
-    readQuery',
     readQuerySingle,
-    readQuerySingle',
-    readQuerySingleMaybe,
-    readQuerySingleMaybe',
     runQuery,
     runQuerySingle,
-    runQuerySingleMaybe,
 
     -- * Filters
     QueryFilter (..),
@@ -58,215 +49,184 @@ module Aztecs.ECS.Query
     -- * Reads and writes
     ReadsWrites (..),
     disjoint,
+
+    -- * QueryStream
+    QueryStream (..),
+
+    -- * Re-exports
+    DynamicQueryF,
   )
 where
 
 import Aztecs.ECS.Access.Internal (Access)
 import Aztecs.ECS.Component
-import Aztecs.ECS.Query.Dynamic
+import Aztecs.ECS.Entity (EntityID)
+import Aztecs.ECS.Query.Dynamic hiding (entity, queryDyn)
+import qualified Aztecs.ECS.Query.Dynamic as DQ
+import Aztecs.ECS.World.Archetype (Archetype)
+import qualified Aztecs.ECS.World.Archetype as A
 import Aztecs.ECS.World.Components (Components)
 import qualified Aztecs.ECS.World.Components as CS
 import Aztecs.ECS.World.Entities (Entities (..))
-import qualified Aztecs.ECS.World.Entities as E
+import Control.Applicative
+import Control.Applicative.Free
+import Control.Monad.Free
+import Control.Monad.Reader
+import Control.Monad.State
 import Data.Set (Set)
 import qualified Data.Set as Set
 import Data.Vector (Vector)
-import GHC.Stack
+import qualified Data.Vector as V
+import GHC.Stack (HasCallStack)
 import Prelude hiding (reads)
 
--- | Query for matching entities.
-newtype Query m a = Query
-  { -- | Run a query, producing a `DynamicQuery`.
-    --
-    -- @since 0.10
-    runQuery' :: Components -> (ReadsWrites, Components, DynamicQuery m a)
-  }
-  deriving (Functor)
+-- | A @Vector@ with zip semantics for @Applicative@.
+newtype QueryStream a = QueryStream {unQueryStream :: Vector a}
+  deriving (Functor, Show)
 
-instance (Monad m) => Applicative (Query m) where
-  pure a = Query (mempty,,pure a)
+instance Applicative QueryStream where
+  pure a = QueryStream (V.singleton a)
   {-# INLINE pure #-}
-
-  (Query f) <*> (Query g) = Query $ \cs ->
-    let !(cIdsG, cs', aQS) = g cs
-        !(cIdsF, cs'', bQS) = f cs'
-     in (cIdsG <> cIdsF, cs'', bQS <*> aQS)
+  QueryStream fs <*> QueryStream xs = QueryStream (V.zipWith ($) fs xs)
   {-# INLINE (<*>) #-}
 
-instance (Monad m) => DynamicQueryF m (Query m) where
-  entity = Query (mempty,,entity)
-  {-# INLINE entity #-}
-
-  queryDyn = dynQueryReader queryDyn
-  {-# INLINE queryDyn #-}
-
-  queryMaybeDyn = dynQueryReader queryMaybeDyn
-  {-# INLINE queryMaybeDyn #-}
-
-  queryMapDyn f = dynQueryWriter' $ queryMapDyn f
-  {-# INLINE queryMapDyn #-}
+data Op f m a where
+  EntityOp :: Op f m (f EntityID)
+  QueryOp :: (Component m a) => ComponentID -> Op f m (f a)
+  QueryMapOp :: (Component m a) => ComponentID -> (f a -> f a) -> Op f m (f a)
+  QueryMapAccumOp :: (Component m b) => ComponentID -> (f b -> f (a, b)) -> Op f m (f (a, b))
 
-  queryMapDyn_ f = dynQueryWriter' $ queryMapDyn_ f
-  {-# INLINE queryMapDyn_ #-}
+newtype QueryBuilder f m a = QueryBuilder {unQueryBuilder :: Free (Ap (Op f m)) a}
+  deriving (Functor, Applicative, Monad)
 
-  queryMapDynM f = dynQueryWriter' $ queryMapDynM f
-  {-# INLINE queryMapDynM #-}
-
-  queryMapDynWith f = dynQueryWriter $ queryMapDynWith f
-  {-# INLINE queryMapDynWith #-}
-
-  queryMapDynWith_ f = dynQueryWriter $ queryMapDynWith_ f
-  {-# INLINE queryMapDynWith_ #-}
-
-  queryMapDynWithM f = dynQueryWriter $ queryMapDynWithM f
-  {-# INLINE queryMapDynWithM #-}
-
-  queryMapDynWithAccum f = dynQueryWriter $ queryMapDynWithAccum f
-  {-# INLINE queryMapDynWithAccum #-}
-
-  queryUntracked (Query q) = Query $ \cs ->
-    let !(rws, cs', dynQ) = q cs
-     in (rws, cs', queryUntracked dynQ)
-  {-# INLINE queryUntracked #-}
-
-  queryMapDynWithAccumM f = dynQueryWriter $ queryMapDynWithAccumM f
-  {-# INLINE queryMapDynWithAccumM #-}
+-- | Query for matching entities.
+newtype Query f m a = Query {unQuery :: ReaderT Components (QueryBuilder f m) a}
+  deriving (Functor, Applicative, Monad)
 
-  queryFilterMap p (Query q) = Query $ \cs ->
-    let !(rws, cs', dynQ) = q cs
-     in (rws, cs', queryFilterMap p dynQ)
-  {-# INLINE queryFilterMap #-}
+-- | Query the entity ID.
+entity :: forall f m. (Applicative f) => Query f m (f EntityID)
+entity = Query . lift . QueryBuilder . liftF . liftAp $ EntityOp
+{-# INLINE entity #-}
 
 -- | Query a component.
-query :: forall m a. (Monad m, Component m a) => Query m a
-query = queryReader @m @a queryDyn
+query :: forall f m a. (Applicative f, Component m a) => Query f m (f a)
+query = Query $ do
+  cs <- ask
+  let !(cId, _) = CS.insert @a @m cs
+  lift . QueryBuilder . liftF . liftAp $ QueryOp cId
 {-# INLINE query #-}
 
--- | Optionally query a component, returning @Nothing@ if it does not exist.
-queryMaybe :: forall m a. (Monad m, Component m a) => Query m (Maybe a)
-queryMaybe = queryReader @m @a queryMaybeDyn
-{-# INLINE queryMaybe #-}
-
 -- | Query a component and update it.
-queryMap :: forall m a. (Monad m, Component m a) => (a -> a) -> Query m a
-queryMap f = queryWriter' @m @a $ queryMapDyn f
+queryMap :: forall f m a. (Applicative f, Component m a) => (f a -> f a) -> Query f m (f a)
+queryMap f = Query $ do
+  cs <- ask
+  let !(cId, _) = CS.insert @a @m cs
+  lift . QueryBuilder . liftF . liftAp $ QueryMapOp cId f
 {-# INLINE queryMap #-}
 
--- | Query a component and update it, ignoring any output.
-queryMap_ :: forall m a. (Monad m, Component m a) => (a -> a) -> Query m ()
-queryMap_ f = queryWriter' @m @a $ queryMapDyn_ f
-{-# INLINE queryMap_ #-}
-
--- | Query a component and update it with a monadic action.
-queryMapM :: forall m a. (Monad m, Component m a) => (a -> m a) -> Query m a
-queryMapM f = queryWriter' @m @a $ queryMapDynM f
-{-# INLINE queryMapM #-}
-
--- | Query a component with input and update it.
-queryMapWith :: forall m a b. (Monad m, Component m b) => (a -> b -> b) -> Query m a -> Query m b
-queryMapWith f = queryWriter @m @b $ queryMapDynWith f
-{-# INLINE queryMapWith #-}
-
--- | Query a component with input and update it, ignoring any output.
-queryMapWith_ :: forall m a b. (Monad m, Component m b) => (a -> b -> b) -> Query m a -> Query m ()
-queryMapWith_ f = queryWriter @m @b $ queryMapDynWith_ f
-{-# INLINE queryMapWith_ #-}
-
--- | Query a component with input and update it with a monadic action.
-queryMapWithM ::
-  forall m a b.
-  (Monad m, Component m b) =>
-  (a -> b -> m b) ->
-  Query m a ->
-  Query m b
-queryMapWithM f = queryWriter @m @b $ queryMapDynWithM f
-{-# INLINE queryMapWithM #-}
-
 -- | Query a component with input, returning a tuple of the result and the updated component.
-queryMapAccum ::
-  forall m a b.
-  (Monad m, Component m b) =>
-  (b -> (a, b)) ->
-  Query m (a, b)
-queryMapAccum f = queryMapWithAccum (const f) (pure ())
+queryMapAccum :: forall f m a b. (Applicative f, Component m b) => (f b -> f (a, b)) -> Query f m (f (a, b))
+queryMapAccum f = Query $ do
+  cs <- ask
+  let !(cId, _) = CS.insert @b @m cs
+  lift . QueryBuilder . liftF . liftAp $ QueryMapAccumOp cId f
 {-# INLINE queryMapAccum #-}
 
--- | Query a component with input and update it with a monadic action, returning a tuple.
-queryMapAccumM ::
-  forall m a b.
-  (Monad m, Component m b) =>
-  (b -> m (a, b)) ->
-  Query m (a, b)
-queryMapAccumM f = queryMapWithAccumM (const f) (pure ())
-{-# INLINE queryMapAccumM #-}
+newtype Fetch a = Fetch (Const () a)
+  deriving (Functor, Applicative)
+
+buildQueryBuilder :: (Monad m) => QueryBuilder QueryStream m (QueryStream a) -> DynamicQuery m a
+buildQueryBuilder a = DynamicQuery $ \arch -> do
+  (as, (arch', hooks)) <- runStateT (foldFree (runAp go) $ unQueryBuilder a) (arch, pure ())
+  return (unQueryStream as, arch', hooks)
+  where
+    go :: (Monad m) => Op QueryStream m x -> StateT (Archetype m, Access m ()) m x
+    go = \case
+      EntityOp -> goEntity
+      QueryOp cId -> goRead cId
+      QueryMapOp cId f -> goWrite cId f
+      QueryMapAccumOp cId f -> goMapAccum cId f
+    goEntity :: (Monad m) => StateT (Archetype m, Access m ()) m (QueryStream EntityID)
+    goEntity = do
+      (arch, _) <- get
+      return $ QueryStream $ V.fromList . Set.toList $ A.entities arch
+    goRead :: forall m a. (Monad m, Component m a) => ComponentID -> StateT (Archetype m, Access m ()) m (QueryStream a)
+    goRead cId = do
+      (arch, hooks) <- get
+      (as, arch', hooks') <- lift $ runDynQuery (DQ.queryDyn cId) arch
+      put (arch', hooks >> hooks')
+      return (QueryStream as)
+    goWrite :: forall m a. (Monad m, Component m a) => ComponentID -> (QueryStream a -> QueryStream a) -> StateT (Archetype m, Access m ()) m (QueryStream a)
+    goWrite cId f = do
+      (arch, hooks) <- get
+      let as = A.lookupComponentsAsc cId arch
+          as' = unQueryStream $ f (QueryStream as)
+          arch' = A.insertAscVector cId as' arch
+      put (arch', hooks)
+      return (QueryStream as')
+    goMapAccum :: forall m a b. (Monad m, Component m b) => ComponentID -> (QueryStream b -> QueryStream (a, b)) -> StateT (Archetype m, Access m ()) m (QueryStream (a, b))
+    goMapAccum cId f = do
+      (arch, hooks) <- get
+      let bs = A.lookupComponentsAsc cId arch
+          xs = unQueryStream $ f (QueryStream bs)
+          arch' = A.insertAscVector cId (fmap snd xs) arch
+      put (arch', hooks)
+      return (QueryStream xs)
+
+runQuery' :: (Monad m) => (forall f. (Applicative f) => Query f m (f a)) -> Components -> (ReadsWrites, Components, DynamicQuery m a)
+runQuery' qb cs =
+  let actionFetch = runReaderT (unQuery qb) cs
+      (_, rws) = runState (foldFree (runAp go) (unQueryBuilder actionFetch)) mempty
+   in (rws, cs, buildQueryBuilder $ runReaderT (unQuery qb) cs)
+  where
+    go :: Op Fetch m x -> State ReadsWrites x
+    go EntityOp = return (Fetch (Const ()))
+    go (QueryOp cId) = do
+      modify (\rws -> rws {reads = Set.insert cId (reads rws)})
+      return (Fetch (Const ()))
+    go (QueryMapOp cId _) = do
+      modify (\rws -> rws {writes = Set.insert cId (writes rws)})
+      return (Fetch (Const ()))
+    go (QueryMapAccumOp cId _) = do
+      modify (\rws -> rws {writes = Set.insert cId (writes rws)})
+      return (Fetch (Const ()))
+
+-- | Query a component dynamically by 'ComponentID'.
+queryDyn :: forall f m a. (Applicative f, Component m a, Monad m) => ComponentID -> Query f m (f a)
+queryDyn cId = Query . lift . QueryBuilder . liftF . liftAp $ QueryOp cId
+{-# INLINE queryDyn #-}
+
+-- | Read all matching entities.
+readQuery :: (Monad m) => (forall f. (Applicative f) => Query f m (f a)) -> Entities m -> m (Vector a, Entities m)
+readQuery q es =
+  let (rws, cs', dynQ) = runQuery' q (components es)
+   in do
+        res <- DQ.readQueryDyn (reads rws <> writes rws) dynQ es
+        return (res, es {components = cs'})
+{-# INLINE readQuery #-}
 
--- | Query a component with input, returning a tuple of the result and the updated component.
-queryMapWithAccum ::
-  forall m a b c.
-  (Monad m, Component m c) =>
-  (b -> c -> (a, c)) ->
-  Query m b ->
-  Query m (a, c)
-queryMapWithAccum f = queryWriter @m @c $ queryMapDynWithAccum f
-{-# INLINE queryMapWithAccum #-}
-
--- | Query a component with input and update it with a monadic action, returning a tuple.
-queryMapWithAccumM ::
-  forall m a b c.
-  (Monad m, Component m c) =>
-  (b -> c -> m (a, c)) ->
-  Query m b ->
-  Query m (a, c)
-queryMapWithAccumM f = queryWriter @m @c $ queryMapDynWithAccumM f
-{-# INLINE queryMapWithAccumM #-}
-
-dynQueryReader :: (ComponentID -> DynamicQuery m a) -> ComponentID -> Query m a
-dynQueryReader f cId = Query (ReadsWrites {reads = Set.singleton cId, writes = Set.empty},,f cId)
-{-# INLINE dynQueryReader #-}
-
-dynQueryWriter ::
-  ( ComponentID ->
-    DynamicQuery m a ->
-    DynamicQuery m b
-  ) ->
-  ComponentID ->
-  Query m a ->
-  Query m b
-dynQueryWriter f cId q = Query $ \cs ->
-  let !(rws, cs', dynQ) = runQuery' q cs
-   in (rws <> ReadsWrites Set.empty (Set.singleton cId), cs', f cId dynQ)
-{-# INLINE dynQueryWriter #-}
-
-dynQueryWriter' :: (ComponentID -> DynamicQuery m a) -> ComponentID -> Query m a
-dynQueryWriter' f cId = Query (ReadsWrites {reads = Set.empty, writes = Set.singleton cId},,f cId)
-{-# INLINE dynQueryWriter' #-}
-
-queryReader :: forall m a b. (Component m a) => (ComponentID -> DynamicQuery m b) -> Query m b
-queryReader f = Query $ \cs ->
-  let !(cId, cs') = CS.insert @a @m cs
-   in (ReadsWrites {reads = Set.singleton cId, writes = Set.empty}, cs', f cId)
-{-# INLINE queryReader #-}
-
-queryWriter ::
-  forall m a b c.
-  (Component m a) =>
-  ( ComponentID ->
-    DynamicQuery m b ->
-    DynamicQuery m c
-  ) ->
-  Query m b ->
-  Query m c
-queryWriter f (Query g) = Query $ \cs ->
-  let !(rws, cs', dynQ) = g cs
-      !(cId, cs'') = CS.insert @a @m cs'
-   in (rws <> ReadsWrites Set.empty (Set.singleton cId), cs'', f cId dynQ)
-{-# INLINE queryWriter #-}
-
-queryWriter' :: forall m a b. (Component m a) => (ComponentID -> DynamicQuery m b) -> Query m b
-queryWriter' f = Query $ \cs ->
-  let !(cId, cs') = CS.insert @a @m cs
-   in (ReadsWrites {reads = Set.empty, writes = Set.singleton cId}, cs', f cId)
-{-# INLINE queryWriter' #-}
+-- | Read a single matching entity.
+readQuerySingle :: (HasCallStack, Monad m) => (forall f. (Applicative f) => Query f m (f a)) -> Entities m -> m (a, Entities m)
+readQuerySingle q es =
+  let (rws, cs', dynQ) = runQuery' q (components es)
+   in do
+        res <- DQ.readQuerySingleDyn (reads rws <> writes rws) dynQ es
+        return (res, es {components = cs'})
+{-# INLINE readQuerySingle #-}
+
+-- | Run a query on all matching entities, potentially modifying them.
+runQuery :: (Monad m) => (forall f. (Applicative f) => Query f m (f a)) -> Entities m -> m (Vector a, Entities m, Access m ())
+runQuery q es =
+  let (rws, cs', dynQ) = runQuery' q $ components es
+   in DQ.runQueryDyn (reads rws <> writes rws) dynQ es {components = cs'}
+{-# INLINE runQuery #-}
+
+-- | Run a query on a single matching entity, potentially modifying it.
+runQuerySingle :: (HasCallStack, Monad m) => (forall f. (Applicative f) => Query f m (f a)) -> Entities m -> m (a, Entities m, Access m ())
+runQuerySingle q es =
+  let (rws, cs', dynQ) = runQuery' q $ components es
+   in DQ.runQuerySingleDyn (reads rws <> writes rws) dynQ es {components = cs'}
+{-# INLINE runQuerySingle #-}
 
 -- | Reads and writes of a `Query`.
 data ReadsWrites = ReadsWrites
@@ -292,89 +252,6 @@ disjoint a b =
     || Set.disjoint (reads b) (writes a)
     || Set.disjoint (writes b) (writes a)
 
--- | Match all entities.
-readQuery :: (Monad m) => Query m a -> Entities m -> m (Vector a, Entities m)
-readQuery q es = do
-  (as, cs) <- readQuery' q es
-  return (as, es {E.components = cs})
-{-# INLINE readQuery #-}
-
--- | Match all entities.
-readQuery' :: (Monad m) => Query m a -> Entities m -> m (Vector a, Components)
-readQuery' q es = do
-  let !(rws, cs', dynQ) = runQuery' q (E.components es)
-      !cIds = reads rws <> writes rws
-  as <- readQueryDyn cIds dynQ es
-  return (as, cs')
-{-# INLINE readQuery' #-}
-
--- | Match a single entity.
-readQuerySingle :: (HasCallStack, Monad m) => Query m a -> Entities m -> m (a, Entities m)
-readQuerySingle q es = do
-  (a, cs) <- readQuerySingle' q es
-  return (a, es {E.components = cs})
-{-# INLINE readQuerySingle #-}
-
--- | Match a single entity.
-readQuerySingle' :: (HasCallStack, Monad m) => Query m a -> Entities m -> m (a, Components)
-readQuerySingle' q es = do
-  let !(rws, cs', dynQ) = runQuery' q (E.components es)
-      !cIds = reads rws <> writes rws
-  a <- readQuerySingleDyn cIds dynQ es
-  return (a, cs')
-{-# INLINE readQuerySingle' #-}
-
--- | Match a single entity.
-readQuerySingleMaybe :: (Monad m) => Query m a -> Entities m -> m (Maybe a, Entities m)
-readQuerySingleMaybe q es = do
-  (a, cs) <- readQuerySingleMaybe' q es
-  return (a, es {E.components = cs})
-{-# INLINE readQuerySingleMaybe #-}
-
--- | Match a single entity.
-readQuerySingleMaybe' :: (Monad m) => Query m a -> Entities m -> m (Maybe a, Components)
-readQuerySingleMaybe' q es = do
-  let !(rws, cs', dynQ) = runQuery' q (E.components es)
-      !cIds = reads rws <> writes rws
-  a <- readQuerySingleMaybeDyn cIds dynQ es
-  return (a, cs')
-{-# INLINE readQuerySingleMaybe' #-}
-
--- | Map all matched entities.
-runQuery :: (Monad m) => Query m o -> Entities m -> m (Vector o, Entities m, Access m ())
-runQuery q es = do
-  let !(rws, cs', dynQ) = runQuery' q $ components es
-      !cIds = reads rws <> writes rws
-  (as, es', hook) <- runQueryDyn cIds dynQ es
-  return (as, es' {components = cs'}, hook)
-{-# INLINE runQuery #-}
-
--- | Map a single matched entity.
-runQuerySingle ::
-  (HasCallStack, Monad m) =>
-  Query m a ->
-  Entities m ->
-  m (a, Entities m, Access m ())
-runQuerySingle q es = do
-  let !(rws, cs', dynQ) = runQuery' q $ components es
-      !cIds = reads rws <> writes rws
-  (as, es', hook) <- runQuerySingleDyn cIds dynQ es
-  return (as, es' {components = cs'}, hook)
-{-# INLINE runQuerySingle #-}
-
--- | Map a single matched entity, or `Nothing`.
-runQuerySingleMaybe ::
-  (Monad m) =>
-  Query m a ->
-  Entities m ->
-  m (Maybe a, Entities m, Access m ())
-runQuerySingleMaybe q es = do
-  let !(rws, cs', dynQ) = runQuery' q $ components es
-      !cIds = reads rws <> writes rws
-  (as, es', hook) <- runQuerySingleMaybeDyn cIds dynQ es
-  return (as, es' {components = cs'}, hook)
-{-# INLINE runQuerySingleMaybe #-}
-
 -- | Filter for a `Query`.
 newtype QueryFilter = QueryFilter
   { -- | Run a query filter.
diff --git a/src/Aztecs/ECS/Query/Dynamic.hs b/src/Aztecs/ECS/Query/Dynamic.hs
index b3ca40c8..f08ea7e5 100644
--- a/src/Aztecs/ECS/Query/Dynamic.hs
+++ b/src/Aztecs/ECS/Query/Dynamic.hs
@@ -47,8 +47,8 @@ import qualified Data.IntMap.Strict as IntMap
 import qualified Data.Map as Map
 import Data.Set (Set)
 import qualified Data.Set as Set
-import Data.Vector (Vector)
-import qualified Data.Vector as V
+import Data.Vector.Strict (Vector)
+import qualified Data.Vector.Strict as V
 import GHC.Stack
 
 -- | Dynamic query for components by ID.
diff --git a/src/Aztecs/ECS/System.hs b/src/Aztecs/ECS/System.hs
index bf968aed..cd8f6481 100644
--- a/src/Aztecs/ECS/System.hs
+++ b/src/Aztecs/ECS/System.hs
@@ -46,7 +46,7 @@ module Aztecs.ECS.System
 where
 
 import Aztecs.ECS.Component
-import Aztecs.ECS.Query (Query (..), QueryFilter (..))
+import Aztecs.ECS.Query (Query, QueryFilter (..))
 import qualified Aztecs.ECS.Query as Q
 import Aztecs.ECS.Query.Dynamic (DynamicQuery, DynamicQueryFilter (..))
 import Aztecs.ECS.System.Dynamic (DynamicSystem (..), runDynamicSystem)
@@ -56,7 +56,7 @@ import Aztecs.ECS.World.Archetypes (Node (..))
 import Aztecs.ECS.World.Components (Components)
 import qualified Data.Foldable as F
 import Data.Set (Set)
-import Data.Vector (Vector)
+import Data.Vector.Strict (Vector)
 import GHC.Stack
 import Prelude hiding (all, filter, map, mapM)
 
@@ -78,47 +78,47 @@ instance Applicative (System m) where
      in (cs'', dynF <*> dynG)
   {-# INLINE (<*>) #-}
 
-runner :: (Set ComponentID -> DynamicQuery m a -> DynamicSystem m b) -> Query m a -> System m b
+runner :: (Monad m) => (Set ComponentID -> DynamicQuery m a -> DynamicSystem m b) -> (forall f. (Applicative f) => Query f m (f a)) -> System m b
 runner f q = System $ \cs ->
-  let (rws, cs', dynQ) = runQuery' q cs
+  let (rws, cs', dynQ) = Q.runQuery' q cs
    in (cs', f (Q.reads rws <> Q.writes rws) dynQ)
 
 -- | Match all entities.
-readQuery :: (Monad m) => Query m a -> System m (Vector a)
+readQuery :: (Monad m) => (forall f. (Applicative f) => Query f m (f a)) -> System m (Vector a)
 readQuery = runner DS.readQuery
 
-readQuerySingle :: (HasCallStack, Monad m) => Query m a -> System m a
+readQuerySingle :: (HasCallStack, Monad m) => (forall f. (Applicative f) => Query f m (f a)) -> System m a
 readQuerySingle = runner DS.readQuerySingle
 
-readQuerySingleMaybe :: (Monad m) => Query m a -> System m (Maybe a)
+readQuerySingleMaybe :: (Monad m) => (forall f. (Applicative f) => Query f m (f a)) -> System m (Maybe a)
 readQuerySingleMaybe = runner DS.readQuerySingleMaybe
 
 -- | Match all entities with a filter.
-readQueryFiltered :: (Monad m) => Query m a -> QueryFilter -> System m (Vector a)
-readQueryFiltered q f = System $ \cs ->
-  let (rws, cs', dynQ) = runQuery' q cs
-      (dynF, cs'') = runQueryFilter f cs'
+readQueryFiltered :: (Monad m) => (forall f. (Applicative f) => Query f m (f a)) -> QueryFilter -> System m (Vector a)
+readQueryFiltered q qf = System $ \cs ->
+  let (rws, cs', dynQ) = Q.runQuery' q cs
+      (dynF, cs'') = runQueryFilter qf cs'
       flt n =
         F.all (\cId -> A.member cId $ nodeArchetype n) (filterWith dynF)
           && F.all (\cId -> not (A.member cId $ nodeArchetype n)) (filterWithout dynF)
    in (cs'', DS.readQueryFiltered (Q.reads rws <> Q.writes rws) flt dynQ)
 
 -- | Map all matching entities.
-runQuery :: (Monad m) => Query m a -> System m (Vector a)
+runQuery :: (Monad m) => (forall f. (Applicative f) => Query f m (f a)) -> System m (Vector a)
 runQuery = runner DS.runQuery
 
-runQuerySingle :: (HasCallStack, Monad m) => Query m a -> System m a
+runQuerySingle :: (HasCallStack, Monad m) => (forall f. (Applicative f) => Query f m (f a)) -> System m a
 runQuerySingle = runner DS.runQuerySingle
 
 -- | Map a single matching entity, or @Nothing@.
-runQuerySingleMaybe :: (Monad m) => Query m a -> System m (Maybe a)
+runQuerySingleMaybe :: (Monad m) => (forall f. (Applicative f) => Query f m (f a)) -> System m (Maybe a)
 runQuerySingleMaybe = runner DS.runQuerySingleMaybe
 
 -- | Filter and map all matching entities.
-runQueryFiltered :: (Monad m) => Query m a -> QueryFilter -> System m (Vector a)
-runQueryFiltered q f = System $ \cs ->
-  let (rws, cs', dynQ) = runQuery' q cs
-      (dynF, cs'') = runQueryFilter f cs'
+runQueryFiltered :: (Monad m) => (forall f. (Applicative f) => Query f m (f a)) -> QueryFilter -> System m (Vector a)
+runQueryFiltered q qf = System $ \cs ->
+  let (rws, cs', dynQ) = Q.runQuery' q cs
+      (dynF, cs'') = runQueryFilter qf cs'
       flt n =
         F.all (\cId -> A.member cId $ nodeArchetype n) (filterWith dynF)
           && F.all (\cId -> not (A.member cId $ nodeArchetype n)) (filterWithout dynF)
diff --git a/src/Aztecs/ECS/System/Dynamic.hs b/src/Aztecs/ECS/System/Dynamic.hs
index 85a82c92..864f157c 100644
--- a/src/Aztecs/ECS/System/Dynamic.hs
+++ b/src/Aztecs/ECS/System/Dynamic.hs
@@ -41,7 +41,7 @@ import qualified Aztecs.ECS.Query.Dynamic as DQ
 import Aztecs.ECS.World.Archetypes (Node (..))
 import Aztecs.ECS.World.Entities (Entities)
 import Data.Set (Set)
-import Data.Vector (Vector)
+import Data.Vector.Strict (Vector)
 import Prelude hiding (all, filter, map, mapM)
 
 -- | Query operation.
diff --git a/src/Aztecs/ECS/View.hs b/src/Aztecs/ECS/View.hs
index 4ec2083c..6e14a5e7 100644
--- a/src/Aztecs/ECS/View.hs
+++ b/src/Aztecs/ECS/View.hs
@@ -37,8 +37,8 @@ import Data.Foldable hiding (null)
 import Data.Map.Strict (Map)
 import qualified Data.Map.Strict as Map
 import Data.Set (Set)
-import Data.Vector (Vector)
-import qualified Data.Vector as V
+import Data.Vector.Strict (Vector)
+import qualified Data.Vector.Strict as V
 import Prelude hiding (null)
 
 -- | View into a `World`, containing a subset of archetypes.
diff --git a/src/Aztecs/ECS/World/Archetype.hs b/src/Aztecs/ECS/World/Archetype.hs
index 2a7acfd3..dd849a2f 100644
--- a/src/Aztecs/ECS/World/Archetype.hs
+++ b/src/Aztecs/ECS/World/Archetype.hs
@@ -60,8 +60,8 @@ import Data.Map (Map)
 import qualified Data.Map as Map
 import Data.Maybe
 import qualified Data.Set as Set
-import Data.Vector (Vector)
-import qualified Data.Vector as V
+import Data.Vector.Strict (Vector)
+import qualified Data.Vector.Strict as V
 import Prelude hiding (map, zipWith)
 
 -- | Archetype with a single entity.
diff --git a/src/Aztecs/ECS/World/Archetypes.hs b/src/Aztecs/ECS/World/Archetypes.hs
index 4d958669..93750373 100644
--- a/src/Aztecs/ECS/World/Archetypes.hs
+++ b/src/Aztecs/ECS/World/Archetypes.hs
@@ -44,7 +44,7 @@ import qualified Data.Map.Strict as Map
 import Data.Maybe
 import Data.Set (Set)
 import qualified Data.Set as Set
-import qualified Data.Vector as V
+import qualified Data.Vector.Strict as V
 import Prelude hiding (all, lookup, map)
 
 -- | Empty `Archetypes`.
diff --git a/src/Aztecs/ECS/World/Storage.hs b/src/Aztecs/ECS/World/Storage.hs
index e22349cd..aba8f54b 100644
--- a/src/Aztecs/ECS/World/Storage.hs
+++ b/src/Aztecs/ECS/World/Storage.hs
@@ -12,8 +12,8 @@
 module Aztecs.ECS.World.Storage (Storage (..)) where
 
 import Data.Data
-import Data.Vector (Vector)
-import qualified Data.Vector as V
+import Data.Vector.Strict (Vector)
+import qualified Data.Vector.Strict as V
 import Prelude hiding (map, zipWith)
 
 -- | Component storage, containing zero or many components of the same type.
diff --git a/src/Aztecs/ECS/World/Storage/Dynamic.hs b/src/Aztecs/ECS/World/Storage/Dynamic.hs
index 7b730f21..253474fe 100644
--- a/src/Aztecs/ECS/World/Storage/Dynamic.hs
+++ b/src/Aztecs/ECS/World/Storage/Dynamic.hs
@@ -28,8 +28,8 @@ where
 import qualified Aztecs.ECS.World.Storage as S
 import Data.Dynamic
 import Data.Maybe
-import Data.Vector (Vector)
-import qualified Data.Vector as V
+import Data.Vector.Strict (Vector)
+import qualified Data.Vector.Strict as V
 
 -- | Dynamic storage of components.
 data DynamicStorage = DynamicStorage
diff --git a/src/Aztecs/Hierarchy.hs b/src/Aztecs/Hierarchy.hs
index 99175489..b22adbdd 100644
--- a/src/Aztecs/Hierarchy.hs
+++ b/src/Aztecs/Hierarchy.hs
@@ -38,13 +38,14 @@ import Aztecs.ECS
 import qualified Aztecs.ECS.Access as A
 import qualified Aztecs.ECS.Query as Q
 import qualified Aztecs.ECS.System as S
+import Control.Applicative (liftA3)
 import Data.Map (Map)
 import qualified Data.Map as Map
 import Data.Maybe
 import Data.Set (Set)
 import qualified Data.Set as Set
-import Data.Vector (Vector)
-import qualified Data.Vector as V
+import Data.Vector.Strict (Vector)
+import qualified Data.Vector.Strict as V
 import GHC.Generics
 
 -- | Parent component.
@@ -139,16 +140,19 @@ mapWithAccum f b n = case f (nodeEntityId n) (nodeEntity n) b of
 
 -- | System to read a hierarchy of parents to children with the given query.
 hierarchy ::
+  forall m a.
   (Monad m) =>
   EntityID ->
-  Query m a ->
+  (forall f. (Applicative f) => Query f m (f a)) ->
   Access m (Maybe (Hierarchy a))
 hierarchy e q = do
-  children <- A.system . S.readQuery $ do
-    e' <- Q.entity
-    cs <- Q.query
-    a <- q
-    return (e', (unChildren cs, a))
+  let mkQuery :: forall f. (Applicative f) => Query f m (f (EntityID, (Set EntityID, a)))
+      mkQuery = do
+        e' <- Q.entity
+        cs <- Q.query @_ @_ @Children
+        a' <- q
+        return $ liftA3 (\eid c a'' -> (eid, (unChildren c, a''))) e' cs a'
+  children <- A.system $ S.readQuery mkQuery
   let childMap = Map.fromList $ V.toList children
   return $ hierarchy' e childMap
 
@@ -156,18 +160,18 @@ hierarchy e q = do
 hierarchies ::
   forall m a.
   (Monad m) =>
-  Query m a ->
+  (forall f. (Applicative f) => Query f m (f a)) ->
   Access m (Vector (Hierarchy a))
 hierarchies q = do
-  children <-
-    A.system . S.readQuery $ do
-      e <- Q.entity
-      cs <- Q.query
-      a <- q
-      return (e, (unChildren cs, a))
-
+  let mkQuery :: forall f. (Applicative f) => Query f m (f (EntityID, (Set EntityID, a)))
+      mkQuery = do
+        e' <- Q.entity
+        cs <- Q.query @_ @_ @Children
+        a' <- q
+        return $ liftA3 (\eid c a -> (eid, (unChildren c, a))) e' cs a'
+  children <- A.system $ S.readQuery mkQuery
   let childMap = Map.fromList $ V.toList children
-  roots <- A.system $ S.readQueryFiltered Q.entity (with @m @Children <> without @m @Parent)
+  roots <- A.system $ S.readQueryFiltered (Q.entity) (with @m @Children <> without @m @Parent)
   return $ V.mapMaybe (`hierarchy'` childMap) roots
 
 -- | Build a hierarchy of parents to children.
diff --git a/test/Main.hs b/test/Main.hs
index ebcafdcb..be1ac85d 100644
--- a/test/Main.hs
+++ b/test/Main.hs
@@ -12,11 +12,12 @@
 module Main (main) where
 
 import Aztecs
-import Aztecs.ECS.Component (ComponentID (ComponentID))
+import Aztecs.ECS.Component
 import qualified Aztecs.ECS.Query as Q
 import qualified Aztecs.ECS.World as W
-import Data.Functor.Identity (Identity (runIdentity))
-import qualified Data.Vector as V
+import Control.Applicative
+import Data.Functor.Identity
+import qualified Data.Vector.Strict as V
 import Data.Word
 import GHC.Generics
 import Test.Hspec
@@ -60,22 +61,28 @@ prop_queryEmpty =
   let res =
         fst
           . runIdentity
-          . Q.readQuery (Q.query @_ @X)
+          . Q.readQuery (Q.query @_ @_ @X)
           $ W.entities W.empty
    in V.toList res `shouldMatchList` []
 
 -- | Query all components from a list of `ComponentID`s.
 queryComponentIds ::
-  forall m q a.
-  (Applicative q, DynamicQueryF m q, Component m a) =>
+  forall a m.
+  (Component m a) =>
   [ComponentID] ->
-  q (EntityID, [a])
-queryComponentIds =
+  (forall f. (Applicative f) => Q.Query f m (f (EntityID, [a])))
+queryComponentIds cIds =
   let go cId qAcc = do
         x' <- Q.queryDyn @_ @_ @a cId
-        (e, xs) <- qAcc
-        return (e, x' : xs)
-   in foldr go ((,) <$> Q.entity <*> pure [])
+        acc <- qAcc
+        return $ liftA2 (\x (e, xs) -> (e, x : xs)) x' acc
+   in foldr
+        go
+        ( do
+            e <- Q.entity
+            return $ fmap (\eid -> (eid, [])) e
+        )
+        cIds
 
 prop_queryDyn :: [[X]] -> Expectation
 prop_queryDyn xs =
@@ -91,46 +98,56 @@ prop_queryDyn xs =
          in ((e, cs) : acc, wAcc')
       (es, w) = foldr spawner ([], W.empty) xs
       go (e, cs) = do
-        let q = queryComponentIds @Identity $ map snd cs
-            (res, _) = runIdentity . Q.readQuery q $ W.entities w
+        let (res, _) = runIdentity . Q.readQuery (queryComponentIds @X @Identity $ map snd cs) $ W.entities w
         return $ V.toList res `shouldContain` [(e, map fst cs)]
    in mapM_ go es
 
 prop_queryTypedComponent :: [X] -> Expectation
 prop_queryTypedComponent xs = do
   let w = foldr (\x -> (\(_, w', _) -> w') . W.spawn (bundle x)) W.empty xs
-      (res, _) = runIdentity . Q.readQuery Q.query $ W.entities w
+      (res, _) = runIdentity . Q.readQuery (Q.query @_ @_ @X) $ W.entities w
   V.toList res `shouldMatchList` xs
 
 prop_queryTwoTypedComponents :: [(X, Y)] -> Expectation
 prop_queryTwoTypedComponents xys = do
   let w = foldr (\(x, y) -> (\(_, w', _) -> w') . W.spawn (bundle x <> bundle y)) W.empty xys
-      (res, _) = runIdentity $ Q.readQuery ((,) <$> Q.query <*> Q.query) $ W.entities w
+      (res, _) =
+        runIdentity
+          $ Q.readQuery
+            ( do
+                x <- Q.query @_ @_ @X
+                y <- Q.query @_ @_ @Y
+                return $ liftA2 (,) x y
+            )
+          $ W.entities w
   V.toList res `shouldMatchList` xys
 
 prop_queryThreeTypedComponents :: [(X, Y, Z)] -> Expectation
 prop_queryThreeTypedComponents xyzs = do
   let w = foldr (\(x, y, z) -> (\(_, w', _) -> w') . W.spawn (bundle x <> bundle y <> bundle z)) W.empty xyzs
-      q = do
-        x <- Q.query
-        y <- Q.query
-        z <- Q.query
-        pure (x, y, z)
-      (res, _) = runIdentity $ Q.readQuery q $ W.entities w
+      (res, _) =
+        runIdentity
+          $ Q.readQuery
+            ( do
+                x <- Q.query @_ @_ @X
+                y <- Q.query @_ @_ @Y
+                z <- Q.query @_ @_ @Z
+                return $ liftA3 (,,) x y z
+            )
+          $ W.entities w
   V.toList res `shouldMatchList` xyzs
 
 prop_querySingle :: Expectation
 prop_querySingle =
   let (_, w, _) = W.spawn (bundle $ X 1) W.empty
-      (res, _) = runIdentity $ Q.readQuerySingle Q.query $ W.entities w
+      (res, _) = runIdentity $ Q.readQuerySingle (Q.query @_ @_ @X) $ W.entities w
    in res `shouldBe` X 1
 
 prop_queryMapSingle :: Word8 -> Expectation
 prop_queryMapSingle n =
   let (_, w, _) = W.spawn (bundle $ X 0) W.empty
-      q = Q.queryMap $ \(X x) -> X $ x + 1
-      w' = foldr (\_ es -> (\(_, es', _) -> es') . runIdentity $ Q.runQuerySingle q es) (W.entities w) [1 .. n]
-      (res, _) = runIdentity $ Q.readQuerySingle Q.query w'
+      w' = foldr (\_ es -> (\(_, es', _) -> es') . runIdentity $ Q.runQuerySingle (Q.queryMap @_ @_ @X $ fmap (\(X x) -> X $ x + 1)) es) (W.entities w) [1 .. n]
+      (res, _) = runIdentity $ Q.readQuerySingle (Q.query @_ @_ @X) w'
    in res `shouldBe` X (fromIntegral n)
 
 {-TODO

From 1479dd241092e2394e96c0031d3f7bf446e56547 Mon Sep 17 00:00:00 2001
From: Matt Hunzinger <matt@hunzinger.me>
Date: Wed, 28 Jan 2026 20:16:57 -0500
Subject: [PATCH 2/6] feat: change Query to work on lists instead of Vectors

---
 aztecs.cabal                            |  6 +-
 bench/Bench.hs                          |  7 +-
 src/Aztecs/ECS/Component.hs             |  3 +-
 src/Aztecs/ECS/Observer.hs              |  3 +-
 src/Aztecs/ECS/Query.hs                 | 20 +++---
 src/Aztecs/ECS/Query/Dynamic.hs         | 86 +++++++++++++------------
 src/Aztecs/ECS/System.hs                | 17 +++--
 src/Aztecs/ECS/System/Dynamic.hs        | 17 +++--
 src/Aztecs/ECS/View.hs                  | 18 +++---
 src/Aztecs/ECS/World/Archetype.hs       | 84 ++++++++++++------------
 src/Aztecs/ECS/World/Archetypes.hs      |  5 +-
 src/Aztecs/ECS/World/Storage.hs         | 50 +++++++-------
 src/Aztecs/ECS/World/Storage/Dynamic.hs | 30 ++++-----
 src/Aztecs/Hierarchy.hs                 | 16 ++---
 test/Main.hs                            | 11 ++--
 15 files changed, 179 insertions(+), 194 deletions(-)

diff --git a/aztecs.cabal b/aztecs.cabal
index 6904de1a..1c94d859 100644
--- a/aztecs.cabal
+++ b/aztecs.cabal
@@ -81,8 +81,7 @@ test-suite aztecs-test
         containers >=0.6,
         deepseq >=1,
         hspec >=2,
-        QuickCheck >=2,
-        vector >=0.12
+        QuickCheck >=2
 
 benchmark aztecs-bench
     type:             exitcode-stdio-1.0
@@ -94,5 +93,4 @@ benchmark aztecs-bench
         base >=4.2 && <5,
         aztecs,
         criterion >=1,
-        deepseq >=1,
-        vector >=0.12
+        deepseq >=1
\ No newline at end of file
diff --git a/bench/Bench.hs b/bench/Bench.hs
index 6314d39a..bd6da069 100644
--- a/bench/Bench.hs
+++ b/bench/Bench.hs
@@ -11,8 +11,7 @@ import Aztecs.ECS.World
 import qualified Aztecs.ECS.World as W
 import Control.DeepSeq
 import Criterion.Main
-import Data.Functor.Identity (Identity (runIdentity))
-import Data.Vector (Vector)
+import Data.Functor.Identity
 import GHC.Generics
 
 newtype Position = Position Int deriving (Show, Generic, NFData)
@@ -28,10 +27,10 @@ move = do
   vs <- Q.query
   Q.queryMap $ \ps -> (\(Velocity v) (Position p) -> Position $ p + v) <$> vs <*> ps
 
-run :: (forall f. (Applicative f) => Q.Query f Identity (f Position)) -> World Identity -> Vector Position
+run :: (forall f. (Applicative f) => Q.Query f Identity (f Position)) -> World Identity -> [Position]
 run q = (\(a, _, _) -> a) . runIdentity . Q.runQuery q . entities
 
-runSys :: (forall f. (Applicative f) => Q.Query f Identity (f Position)) -> World Identity -> Vector Position
+runSys :: (forall f. (Applicative f) => Q.Query f Identity (f Position)) -> World Identity -> [Position]
 runSys q = fst . runIdentity . runAccess (system $ runQuery q)
 
 main :: IO ()
diff --git a/src/Aztecs/ECS/Component.hs b/src/Aztecs/ECS/Component.hs
index ae6dcb36..d8d35ad2 100644
--- a/src/Aztecs/ECS/Component.hs
+++ b/src/Aztecs/ECS/Component.hs
@@ -21,14 +21,13 @@ import Aztecs.ECS.Component.Internal (ComponentID (..))
 import Aztecs.ECS.Entity
 import Aztecs.ECS.World.Storage
 import Data.Typeable
-import Data.Vector.Strict (Vector)
 
 -- | Component that can be stored in the `World`.
 class (Monad m, Typeable a, Storage a (StorageT a)) => Component m a where
   -- | `Storage` of this component.
   type StorageT a
 
-  type StorageT a = Vector a
+  type StorageT a = [a]
 
   -- | Lifecycle hook called when a component is inserted.
   componentOnInsert :: EntityID -> a -> Access m ()
diff --git a/src/Aztecs/ECS/Observer.hs b/src/Aztecs/ECS/Observer.hs
index dd20072b..df19bfca 100644
--- a/src/Aztecs/ECS/Observer.hs
+++ b/src/Aztecs/ECS/Observer.hs
@@ -39,7 +39,6 @@ import Control.Monad.State
 import Data.Set (Set)
 import qualified Data.Set as Set
 import Data.Typeable
-import Data.Vector.Strict (Vector)
 
 -- | The kind of observer - either entity-specific or global.
 data ObserverKind m e
@@ -64,7 +63,7 @@ instance Show (Observer m e) where
   show o = "Observer { kind = " ++ show (observerKind o) ++ ", id = " ++ show (observerId o) ++ " }"
 
 instance (Monad m, Typeable m, Event e) => Component m (Observer m e) where
-  type StorageT (Observer m e) = Vector (Observer m e)
+  type StorageT (Observer m e) = [Observer m e]
 
   componentOnInsert ownerEntity o = Access $ do
     !w <- get
diff --git a/src/Aztecs/ECS/Query.hs b/src/Aztecs/ECS/Query.hs
index 8b65e038..a87fb0d9 100644
--- a/src/Aztecs/ECS/Query.hs
+++ b/src/Aztecs/ECS/Query.hs
@@ -75,19 +75,17 @@ import Control.Monad.Reader
 import Control.Monad.State
 import Data.Set (Set)
 import qualified Data.Set as Set
-import Data.Vector (Vector)
-import qualified Data.Vector as V
 import GHC.Stack (HasCallStack)
 import Prelude hiding (reads)
 
--- | A @Vector@ with zip semantics for @Applicative@.
-newtype QueryStream a = QueryStream {unQueryStream :: Vector a}
+-- | A list with zip semantics for @Applicative@.
+newtype QueryStream a = QueryStream {unQueryStream :: [a]}
   deriving (Functor, Show)
 
 instance Applicative QueryStream where
-  pure a = QueryStream (V.singleton a)
+  pure a = QueryStream [a]
   {-# INLINE pure #-}
-  QueryStream fs <*> QueryStream xs = QueryStream (V.zipWith ($) fs xs)
+  QueryStream fs <*> QueryStream xs = QueryStream (zipWith ($) fs xs)
   {-# INLINE (<*>) #-}
 
 data Op f m a where
@@ -149,7 +147,7 @@ buildQueryBuilder a = DynamicQuery $ \arch -> do
     goEntity :: (Monad m) => StateT (Archetype m, Access m ()) m (QueryStream EntityID)
     goEntity = do
       (arch, _) <- get
-      return $ QueryStream $ V.fromList . Set.toList $ A.entities arch
+      return $ QueryStream $ Set.toList $ A.entities arch
     goRead :: forall m a. (Monad m, Component m a) => ComponentID -> StateT (Archetype m, Access m ()) m (QueryStream a)
     goRead cId = do
       (arch, hooks) <- get
@@ -161,7 +159,7 @@ buildQueryBuilder a = DynamicQuery $ \arch -> do
       (arch, hooks) <- get
       let as = A.lookupComponentsAsc cId arch
           as' = unQueryStream $ f (QueryStream as)
-          arch' = A.insertAscVector cId as' arch
+          arch' = A.insertAscList cId as' arch
       put (arch', hooks)
       return (QueryStream as')
     goMapAccum :: forall m a b. (Monad m, Component m b) => ComponentID -> (QueryStream b -> QueryStream (a, b)) -> StateT (Archetype m, Access m ()) m (QueryStream (a, b))
@@ -169,7 +167,7 @@ buildQueryBuilder a = DynamicQuery $ \arch -> do
       (arch, hooks) <- get
       let bs = A.lookupComponentsAsc cId arch
           xs = unQueryStream $ f (QueryStream bs)
-          arch' = A.insertAscVector cId (fmap snd xs) arch
+          arch' = A.insertAscList cId (fmap snd xs) arch
       put (arch', hooks)
       return (QueryStream xs)
 
@@ -197,7 +195,7 @@ queryDyn cId = Query . lift . QueryBuilder . liftF . liftAp $ QueryOp cId
 {-# INLINE queryDyn #-}
 
 -- | Read all matching entities.
-readQuery :: (Monad m) => (forall f. (Applicative f) => Query f m (f a)) -> Entities m -> m (Vector a, Entities m)
+readQuery :: (Monad m) => (forall f. (Applicative f) => Query f m (f a)) -> Entities m -> m ([a], Entities m)
 readQuery q es =
   let (rws, cs', dynQ) = runQuery' q (components es)
    in do
@@ -215,7 +213,7 @@ readQuerySingle q es =
 {-# INLINE readQuerySingle #-}
 
 -- | Run a query on all matching entities, potentially modifying them.
-runQuery :: (Monad m) => (forall f. (Applicative f) => Query f m (f a)) -> Entities m -> m (Vector a, Entities m, Access m ())
+runQuery :: (Monad m) => (forall f. (Applicative f) => Query f m (f a)) -> Entities m -> m ([a], Entities m, Access m ())
 runQuery q es =
   let (rws, cs', dynQ) = runQuery' q $ components es
    in DQ.runQueryDyn (reads rws <> writes rws) dynQ es {components = cs'}
diff --git a/src/Aztecs/ECS/Query/Dynamic.hs b/src/Aztecs/ECS/Query/Dynamic.hs
index f08ea7e5..f66eac8e 100644
--- a/src/Aztecs/ECS/Query/Dynamic.hs
+++ b/src/Aztecs/ECS/Query/Dynamic.hs
@@ -47,8 +47,6 @@ import qualified Data.IntMap.Strict as IntMap
 import qualified Data.Map as Map
 import Data.Set (Set)
 import qualified Data.Set as Set
-import Data.Vector.Strict (Vector)
-import qualified Data.Vector.Strict as V
 import GHC.Stack
 
 -- | Dynamic query for components by ID.
@@ -57,12 +55,12 @@ newtype DynamicQuery m a
   { -- | Run a dynamic query.
     --
     -- @since 0.10
-    runDynQuery :: Archetype m -> m (Vector a, Archetype m, Access m ())
+    runDynQuery :: Archetype m -> m ([a], Archetype m, Access m ())
   }
   deriving (Functor)
 
 instance (Monad m) => Applicative (DynamicQuery m) where
-  pure a = DynamicQuery $ \arch -> pure (V.replicate (length $ A.entities arch) a, arch, return ())
+  pure a = DynamicQuery $ \arch -> pure (replicate (length $ A.entities arch) a, arch, return ())
   {-# INLINE pure #-}
 
   f <*> g = DynamicQuery $ \arch -> do
@@ -71,33 +69,33 @@ instance (Monad m) => Applicative (DynamicQuery m) where
     return $
       let (as, arch', hook1) = x
           (bs, arch'', hook2) = y
-       in (V.zipWith ($) bs as, arch' <> arch'', hook1 >> hook2)
+       in (zipWith ($) bs as, arch' <> arch'', hook1 >> hook2)
   {-# INLINE (<*>) #-}
 
 instance (Monad m) => DynamicQueryF m (DynamicQuery m) where
-  entity = DynamicQuery $ \arch -> pure (V.fromList . Set.toList $ A.entities arch, arch, return ())
+  entity = DynamicQuery $ \arch -> pure (Set.toList $ A.entities arch, arch, return ())
   {-# INLINE entity #-}
 
   queryDyn cId = DynamicQuery $ \arch -> pure (A.lookupComponentsAsc cId arch, arch, return ())
   {-# INLINE queryDyn #-}
 
   queryMaybeDyn cId = DynamicQuery $ \arch -> case A.lookupComponentsAscMaybe cId arch of
-    Just as -> pure (V.map Just as, arch, return ())
-    Nothing -> pure (V.replicate (length $ A.entities arch) Nothing, arch, return ())
+    Just as -> pure (map Just as, arch, return ())
+    Nothing -> pure (replicate (length $ A.entities arch) Nothing, arch, return ())
   {-# INLINE queryMaybeDyn #-}
 
   queryMapDyn f cId = DynamicQuery $ \arch -> do
-    let (cs, arch', hook) = A.zipWith (V.replicate (length $ A.entities arch) ()) (const f) cId arch
+    let (cs, arch', hook) = A.zipWith (replicate (length $ A.entities arch) ()) (const f) cId arch
     return (cs, arch', hook)
   {-# INLINE queryMapDyn #-}
 
   queryMapDyn_ f cId = DynamicQuery $ \arch -> do
-    let (arch', hook) = A.zipWith_ (V.replicate (length $ A.entities arch) ()) (const f) cId arch
-    return (V.replicate (length $ A.entities arch) (), arch', hook)
+    let (arch', hook) = A.zipWith_ (replicate (length $ A.entities arch) ()) (const f) cId arch
+    return (replicate (length $ A.entities arch) (), arch', hook)
   {-# INLINE queryMapDyn_ #-}
 
   queryMapDynM f cId = DynamicQuery $ \arch -> do
-    (cs, arch', hook) <- A.zipWithM (V.replicate (length $ A.entities arch) ()) (const f) cId arch
+    (cs, arch', hook) <- A.zipWithM (replicate (length $ A.entities arch) ()) (const f) cId arch
     return (cs, arch', hook)
   {-# INLINE queryMapDynM #-}
 
@@ -110,7 +108,7 @@ instance (Monad m) => DynamicQueryF m (DynamicQuery m) where
   queryMapDynWith_ f cId q = DynamicQuery $ \arch -> do
     (as, arch', hook1) <- runDynQuery q arch
     let (arch'', hook2) = A.zipWith_ as f cId arch'
-    return (V.map (const ()) as, arch'', hook1 >> hook2)
+    return (map (const ()) as, arch'', hook1 >> hook2)
   {-# INLINE queryMapDynWith_ #-}
 
   queryMapDynWithM f cId q = DynamicQuery $ \arch -> do
@@ -138,51 +136,54 @@ instance (Monad m) => DynamicQueryF m (DynamicQuery m) where
 
   queryFilterMap p q = DynamicQuery $ \arch -> do
     (as, _, _) <- runDynQuery q arch
-    let eIds = V.fromList . Set.toList $ A.entities arch
-        mapped = V.map p as
-        (filteredEIds, indices, filteredBs) = V.unzip3 . V.imapMaybe (\i (e, mb) -> (\b -> (e, i, b)) <$> mb) $ V.zip eIds mapped
+    let eIds = Set.toList $ A.entities arch
+        mapped = map p as
+        withIndices = zip3 eIds [0 ..] mapped
+        filtered = [(e, i, b) | (e, i, Just b) <- withIndices]
+        (filteredEIds, indices, filteredBs) = unzip3 filtered
         filteredArch = filterArchetype indices arch
-    (_, filteredArch', hook) <- runDynQuery q filteredArch {A.entities = Set.fromList $ V.toList filteredEIds}
+    (_, filteredArch', hook) <- runDynQuery q filteredArch {A.entities = Set.fromList filteredEIds}
     let resultArch = unfilterArchetype indices arch filteredArch'
     return (filteredBs, resultArch, hook)
     where
       filterArchetype indices arch =
         arch {A.storages = IntMap.map (filterStorage indices) $ A.storages arch}
       filterStorage indices s =
-        let allVec = toAscVectorDyn s
-            filteredVec = V.map (allVec V.!) indices
-         in fromAscVectorDyn filteredVec s
+        let allList = toAscListDyn s
+            filteredList = map (allList !!) indices
+         in fromAscListDyn filteredList s
       unfilterArchetype indices original filtered =
         original {A.storages = IntMap.mapWithKey go $ A.storages original}
         where
           go cId s = case IntMap.lookup cId (A.storages filtered) of
             Just filteredStorage ->
-              let origVec = toAscVectorDyn s
-                  filteredVec = toAscVectorDyn filteredStorage
-                  mergedVec = V.accum (\_ new -> new) origVec (V.toList $ V.zip indices filteredVec)
-               in fromAscVectorDyn mergedVec s
+              let origList = toAscListDyn s
+                  filteredList = toAscListDyn filteredStorage
+                  updates = zip indices filteredList
+                  mergedList = foldr (\(i, v) acc -> take i acc ++ [v] ++ drop (i + 1) acc) origList updates
+               in fromAscListDyn mergedList s
             Nothing -> s
   {-# INLINE queryFilterMap #-}
 
 -- | Match all entities.
-readQueryDyn :: (Monad m) => Set ComponentID -> DynamicQuery m a -> Entities m -> m (Vector a)
+readQueryDyn :: (Monad m) => Set ComponentID -> DynamicQuery m a -> Entities m -> m [a]
 readQueryDyn cIds q es =
   if Set.null cIds
     then (\(a, _, _) -> a) <$> runDynQuery q A.empty {A.entities = Map.keysSet $ entities es}
     else do
       let go n = (\(a, _, _) -> a) <$> runDynQuery q (AS.nodeArchetype n)
       results <- mapM go . Map.elems $ AS.find cIds $ archetypes es
-      return $ V.concat results
+      return $ concat results
 
 -- | Match all entities with a filter.
-readQueryFilteredDyn :: (Monad m) => Set ComponentID -> (Node m -> Bool) -> DynamicQuery m a -> Entities m -> m (Vector a)
+readQueryFilteredDyn :: (Monad m) => Set ComponentID -> (Node m -> Bool) -> DynamicQuery m a -> Entities m -> m [a]
 readQueryFilteredDyn cIds f q es =
   if Set.null cIds
     then (\(a, _, _) -> a) <$> runDynQuery q A.empty {A.entities = Map.keysSet $ entities es}
     else do
       let go n = (\(a, _, _) -> a) <$> runDynQuery q (AS.nodeArchetype n)
       results <- mapM go . Map.elems . Map.filter f $ AS.find cIds $ archetypes es
-      return $ V.concat results
+      return $ concat results
 
 -- | Match a single entity.
 readQuerySingleDyn :: (HasCallStack, Monad m) => Set ComponentID -> DynamicQuery m a -> Entities m -> m a
@@ -199,16 +200,20 @@ readQuerySingleMaybeDyn cIds q es =
     then case Map.keys $ entities es of
       [eId] -> do
         (v, _, _) <- runDynQuery q $ A.singleton eId
-        return $ if V.length v == 1 then Just (V.head v) else Nothing
+        return $ case v of
+          [x] -> Just x
+          _ -> Nothing
       _ -> return Nothing
     else case Map.elems $ AS.find cIds $ archetypes es of
       [n] -> do
         (v, _, _) <- runDynQuery q $ AS.nodeArchetype n
-        return $ if V.length v == 1 then Just (V.head v) else Nothing
+        return $ case v of
+          [x] -> Just x
+          _ -> Nothing
       _ -> return Nothing
 
 -- | Map all matched entities.
-runQueryDyn :: (Monad m) => Set ComponentID -> DynamicQuery m a -> Entities m -> m (Vector a, Entities m, Access m ())
+runQueryDyn :: (Monad m) => Set ComponentID -> DynamicQuery m a -> Entities m -> m ([a], Entities m, Access m ())
 runQueryDyn cIds q es =
   let go = runDynQuery q
    in if Set.null cIds
@@ -219,12 +224,12 @@ runQueryDyn cIds q es =
           let go' (acc, esAcc, hooks) (aId, n) = do
                 (as', arch', hook) <- go $ nodeArchetype n
                 let !nodes = Map.insert aId n {nodeArchetype = arch' <> nodeArchetype n} . AS.nodes $ archetypes esAcc
-                return (as' V.++ acc, esAcc {archetypes = (archetypes esAcc) {AS.nodes = nodes}}, hooks >> hook)
-           in foldlM go' (V.empty, es, return ()) $ Map.toList . AS.find cIds $ archetypes es
+                return (as' ++ acc, esAcc {archetypes = (archetypes esAcc) {AS.nodes = nodes}}, hooks >> hook)
+           in foldlM go' ([], es, return ()) $ Map.toList . AS.find cIds $ archetypes es
 {-# INLINE runQueryDyn #-}
 
 -- | Map all matched entities.
-runQueryFilteredDyn :: (Monad m) => Set ComponentID -> (Node m -> Bool) -> DynamicQuery m a -> Entities m -> m (Vector a, Entities m, Access m ())
+runQueryFilteredDyn :: (Monad m) => Set ComponentID -> (Node m -> Bool) -> DynamicQuery m a -> Entities m -> m ([a], Entities m, Access m ())
 runQueryFilteredDyn cIds f q es =
   let go = runDynQuery q
    in if Set.null cIds
@@ -235,8 +240,8 @@ runQueryFilteredDyn cIds f q es =
           let go' (acc, esAcc, hooks) (aId, n) = do
                 (as', arch', hook) <- go $ nodeArchetype n
                 let !nodes = Map.insert aId n {nodeArchetype = arch' <> nodeArchetype n} . AS.nodes $ archetypes esAcc
-                return (as' V.++ acc, esAcc {archetypes = (archetypes esAcc) {AS.nodes = nodes}}, hooks >> hook)
-           in foldlM go' (V.empty, es, return ()) $ Map.toList . Map.filter f . AS.find cIds $ archetypes es
+                return (as' ++ acc, esAcc {archetypes = (archetypes esAcc) {AS.nodes = nodes}}, hooks >> hook)
+           in foldlM go' ([], es, return ()) $ Map.toList . Map.filter f . AS.find cIds $ archetypes es
 {-# INLINE runQueryFilteredDyn #-}
 
 -- | Map a single matched entity.
@@ -255,17 +260,16 @@ runQuerySingleMaybeDyn cIds q es =
       [eId] -> do
         res <- runDynQuery q $ A.singleton eId
         return $ case res of
-          (v, _, hook) | V.length v == 1 -> (Just (V.head v), es, hook)
+          ([x], _, hook) -> (Just x, es, hook)
           _ -> (Nothing, es, return ())
       _ -> pure (Nothing, es, return ())
     else case Map.toList $ AS.find cIds $ archetypes es of
       [(aId, n)] -> do
         res <- runDynQuery q $ AS.nodeArchetype n
         return $ case res of
-          (v, arch', hook)
-            | V.length v == 1 ->
-                let nodes = Map.insert aId n {nodeArchetype = arch' <> nodeArchetype n} . AS.nodes $ archetypes es
-                 in (Just (V.head v), es {archetypes = (archetypes es) {AS.nodes = nodes}}, hook)
+          ([x], arch', hook) ->
+            let nodes = Map.insert aId n {nodeArchetype = arch' <> nodeArchetype n} . AS.nodes $ archetypes es
+             in (Just x, es {archetypes = (archetypes es) {AS.nodes = nodes}}, hook)
           _ -> (Nothing, es, return ())
       _ -> pure (Nothing, es, return ())
 {-# INLINE runQuerySingleMaybeDyn #-}
diff --git a/src/Aztecs/ECS/System.hs b/src/Aztecs/ECS/System.hs
index cd8f6481..5f13b8b4 100644
--- a/src/Aztecs/ECS/System.hs
+++ b/src/Aztecs/ECS/System.hs
@@ -56,7 +56,6 @@ import Aztecs.ECS.World.Archetypes (Node (..))
 import Aztecs.ECS.World.Components (Components)
 import qualified Data.Foldable as F
 import Data.Set (Set)
-import Data.Vector.Strict (Vector)
 import GHC.Stack
 import Prelude hiding (all, filter, map, mapM)
 
@@ -84,7 +83,7 @@ runner f q = System $ \cs ->
    in (cs', f (Q.reads rws <> Q.writes rws) dynQ)
 
 -- | Match all entities.
-readQuery :: (Monad m) => (forall f. (Applicative f) => Query f m (f a)) -> System m (Vector a)
+readQuery :: (Monad m) => (forall f. (Applicative f) => Query f m (f a)) -> System m [a]
 readQuery = runner DS.readQuery
 
 readQuerySingle :: (HasCallStack, Monad m) => (forall f. (Applicative f) => Query f m (f a)) -> System m a
@@ -94,7 +93,7 @@ readQuerySingleMaybe :: (Monad m) => (forall f. (Applicative f) => Query f m (f
 readQuerySingleMaybe = runner DS.readQuerySingleMaybe
 
 -- | Match all entities with a filter.
-readQueryFiltered :: (Monad m) => (forall f. (Applicative f) => Query f m (f a)) -> QueryFilter -> System m (Vector a)
+readQueryFiltered :: (Monad m) => (forall f. (Applicative f) => Query f m (f a)) -> QueryFilter -> System m [a]
 readQueryFiltered q qf = System $ \cs ->
   let (rws, cs', dynQ) = Q.runQuery' q cs
       (dynF, cs'') = runQueryFilter qf cs'
@@ -104,7 +103,7 @@ readQueryFiltered q qf = System $ \cs ->
    in (cs'', DS.readQueryFiltered (Q.reads rws <> Q.writes rws) flt dynQ)
 
 -- | Map all matching entities.
-runQuery :: (Monad m) => (forall f. (Applicative f) => Query f m (f a)) -> System m (Vector a)
+runQuery :: (Monad m) => (forall f. (Applicative f) => Query f m (f a)) -> System m [a]
 runQuery = runner DS.runQuery
 
 runQuerySingle :: (HasCallStack, Monad m) => (forall f. (Applicative f) => Query f m (f a)) -> System m a
@@ -115,7 +114,7 @@ runQuerySingleMaybe :: (Monad m) => (forall f. (Applicative f) => Query f m (f a
 runQuerySingleMaybe = runner DS.runQuerySingleMaybe
 
 -- | Filter and map all matching entities.
-runQueryFiltered :: (Monad m) => (forall f. (Applicative f) => Query f m (f a)) -> QueryFilter -> System m (Vector a)
+runQueryFiltered :: (Monad m) => (forall f. (Applicative f) => Query f m (f a)) -> QueryFilter -> System m [a]
 runQueryFiltered q qf = System $ \cs ->
   let (rws, cs', dynQ) = Q.runQuery' q cs
       (dynF, cs'') = runQueryFilter qf cs'
@@ -125,18 +124,18 @@ runQueryFiltered q qf = System $ \cs ->
    in (cs'', DS.runQueryFiltered (Q.reads rws <> Q.writes rws) dynQ flt)
 
 -- | Match all entities with a dynamic query.
-readQueryDyn :: Set ComponentID -> DynamicQuery m a -> System m (Vector a)
+readQueryDyn :: Set ComponentID -> DynamicQuery m a -> System m [a]
 readQueryDyn cIds q = System (,DS.readQuery cIds q)
 
 readQuerySingleMaybeDyn :: Set ComponentID -> DynamicQuery m a -> System m (Maybe a)
 readQuerySingleMaybeDyn cIds q = System (,DS.readQuerySingleMaybe cIds q)
 
 -- | Match all entities with a dynamic query and filter.
-readQueryFilteredDyn :: Set ComponentID -> DynamicQuery m a -> (Node m -> Bool) -> System m (Vector a)
+readQueryFilteredDyn :: Set ComponentID -> DynamicQuery m a -> (Node m -> Bool) -> System m [a]
 readQueryFilteredDyn cIds q f = System (,DS.readQueryFiltered cIds f q)
 
 -- | Map all entities with a dynamic query.
-runQueryDyn :: Set ComponentID -> DynamicQuery m a -> System m (Vector a)
+runQueryDyn :: Set ComponentID -> DynamicQuery m a -> System m [a]
 runQueryDyn cIds q = System (,DS.runQuery cIds q)
 
 -- | Map a single entity with a dynamic query.
@@ -144,5 +143,5 @@ runQuerySingleMaybeDyn :: Set ComponentID -> DynamicQuery m a -> System m (Maybe
 runQuerySingleMaybeDyn cIds q = System (,DS.runQuerySingleMaybe cIds q)
 
 -- | Filter and map all entities with a dynamic query.
-runQueryFilteredDyn :: Set ComponentID -> (Node m -> Bool) -> DynamicQuery m a -> System m (Vector a)
+runQueryFilteredDyn :: Set ComponentID -> (Node m -> Bool) -> DynamicQuery m a -> System m [a]
 runQueryFilteredDyn cIds f q = System (,DS.runQueryFiltered cIds q f)
diff --git a/src/Aztecs/ECS/System/Dynamic.hs b/src/Aztecs/ECS/System/Dynamic.hs
index 864f157c..9ab2772b 100644
--- a/src/Aztecs/ECS/System/Dynamic.hs
+++ b/src/Aztecs/ECS/System/Dynamic.hs
@@ -41,17 +41,16 @@ import qualified Aztecs.ECS.Query.Dynamic as DQ
 import Aztecs.ECS.World.Archetypes (Node (..))
 import Aztecs.ECS.World.Entities (Entities)
 import Data.Set (Set)
-import Data.Vector.Strict (Vector)
 import Prelude hiding (all, filter, map, mapM)
 
 -- | Query operation.
 data Op m a where
-  RunQuery :: DynamicQuery m a -> Op m (Vector a)
-  RunFiltered :: (Node m -> Bool) -> DynamicQuery m a -> Op m (Vector a)
+  RunQuery :: DynamicQuery m a -> Op m [a]
+  RunFiltered :: (Node m -> Bool) -> DynamicQuery m a -> Op m [a]
   RunQuerySingle :: DynamicQuery m a -> Op m a
   RunQuerySingleMaybe :: DynamicQuery m a -> Op m (Maybe a)
-  ReadQuery :: DynamicQuery m a -> Op m (Vector a)
-  ReadQueryFiltered :: DynamicQuery m a -> (Node m -> Bool) -> Op m (Vector a)
+  ReadQuery :: DynamicQuery m a -> Op m [a]
+  ReadQueryFiltered :: DynamicQuery m a -> (Node m -> Bool) -> Op m [a]
   ReadQuerySingle :: DynamicQuery m a -> Op m a
   ReadQuerySingleMaybe :: DynamicQuery m a -> Op m (Maybe a)
 
@@ -113,11 +112,11 @@ runDynamicSystem (Ap sf sa) es = do
 runDynamicSystem (Op cIds op) es = runOp cIds op es
 {-# INLINE runDynamicSystem #-}
 
-runQuery :: Set ComponentID -> DynamicQuery m a -> DynamicSystem m (Vector a)
+runQuery :: Set ComponentID -> DynamicQuery m a -> DynamicSystem m [a]
 runQuery cIds q = Op cIds (RunQuery q)
 {-# INLINE runQuery #-}
 
-runQueryFiltered :: Set ComponentID -> DynamicQuery m a -> (Node m -> Bool) -> DynamicSystem m (Vector a)
+runQueryFiltered :: Set ComponentID -> DynamicQuery m a -> (Node m -> Bool) -> DynamicSystem m [a]
 runQueryFiltered cIds q flt = Op cIds (RunFiltered flt q)
 {-# INLINE runQueryFiltered #-}
 
@@ -129,11 +128,11 @@ runQuerySingleMaybe :: Set ComponentID -> DynamicQuery m a -> DynamicSystem m (M
 runQuerySingleMaybe cIds q = Op cIds (RunQuerySingleMaybe q)
 {-# INLINE runQuerySingleMaybe #-}
 
-readQuery :: Set ComponentID -> DynamicQuery m a -> DynamicSystem m (Vector a)
+readQuery :: Set ComponentID -> DynamicQuery m a -> DynamicSystem m [a]
 readQuery cIds q = Op cIds (ReadQuery q)
 {-# INLINE readQuery #-}
 
-readQueryFiltered :: Set ComponentID -> (Node m -> Bool) -> DynamicQuery m a -> DynamicSystem m (Vector a)
+readQueryFiltered :: Set ComponentID -> (Node m -> Bool) -> DynamicQuery m a -> DynamicSystem m [a]
 readQueryFiltered cIds flt q = Op cIds (ReadQueryFiltered q flt)
 {-# INLINE readQueryFiltered #-}
 
diff --git a/src/Aztecs/ECS/View.hs b/src/Aztecs/ECS/View.hs
index 6e14a5e7..596acd25 100644
--- a/src/Aztecs/ECS/View.hs
+++ b/src/Aztecs/ECS/View.hs
@@ -37,8 +37,6 @@ import Data.Foldable hiding (null)
 import Data.Map.Strict (Map)
 import qualified Data.Map.Strict as Map
 import Data.Set (Set)
-import Data.Vector.Strict (Vector)
-import qualified Data.Vector.Strict as V
 import Prelude hiding (null)
 
 -- | View into a `World`, containing a subset of archetypes.
@@ -82,32 +80,32 @@ unview v es =
     }
 
 -- | Query all matching entities in a `View`.
-allDyn :: DynamicQuery Identity a -> View Identity -> Vector a
+allDyn :: DynamicQuery Identity a -> View Identity -> [a]
 allDyn q v =
   foldl'
     ( \acc n ->
         let (as, _, _) = runIdentity . runDynQuery q $ nodeArchetype n
-         in as V.++ acc
+         in as ++ acc
     )
-    V.empty
+    []
     (viewArchetypes v)
 
 -- | Query all matching entities in a `View`.
 singleDyn :: DynamicQuery Identity a -> View Identity -> Maybe a
 singleDyn q v = case allDyn q v of
-  as | V.length as == 1 -> Just (V.head as)
+  [x] -> Just x
   _ -> Nothing
 
 -- | Map all matching entities in a `View`. Returns the results, updated view, and hooks to run.
-mapDyn :: (Monad m) => DynamicQuery m a -> View m -> m (Vector a, View m, Access m ())
+mapDyn :: (Monad m) => DynamicQuery m a -> View m -> m ([a], View m, Access m ())
 mapDyn q v = do
   (as, arches, hooks) <-
     foldlM
       ( \(acc, archAcc, hooksAcc) (aId, n) -> do
           (as', arch', hook) <- runDynQuery q $ nodeArchetype n
-          return (as' V.++ acc, Map.insert aId (n {nodeArchetype = arch'}) archAcc, hooksAcc >> hook)
+          return (as' ++ acc, Map.insert aId (n {nodeArchetype = arch'}) archAcc, hooksAcc >> hook)
       )
-      (V.empty, Map.empty, return ())
+      ([], Map.empty, return ())
       (Map.toList $ viewArchetypes v)
   return (as, View arches, hooks)
 
@@ -116,5 +114,5 @@ mapSingleDyn :: (Monad m) => DynamicQuery m a -> View m -> m (Maybe a, View m, A
 mapSingleDyn q v = do
   (as, arches, hooks) <- mapDyn q v
   return $ case as of
-    a | V.length a == 1 -> (Just (V.head a), arches, hooks)
+    [x] -> (Just x, arches, hooks)
     _ -> (Nothing, arches, hooks)
diff --git a/src/Aztecs/ECS/World/Archetype.hs b/src/Aztecs/ECS/World/Archetype.hs
index dd849a2f..57acbea4 100644
--- a/src/Aztecs/ECS/World/Archetype.hs
+++ b/src/Aztecs/ECS/World/Archetype.hs
@@ -34,7 +34,7 @@ module Aztecs.ECS.World.Archetype
     insertComponent,
     insertComponentUntracked,
     insertComponents,
-    insertAscVector,
+    insertAscList,
     zipWith,
     zipWith_,
     zipWithM,
@@ -60,8 +60,6 @@ import Data.Map (Map)
 import qualified Data.Map as Map
 import Data.Maybe
 import qualified Data.Set as Set
-import Data.Vector.Strict (Vector)
-import qualified Data.Vector.Strict as V
 import Prelude hiding (map, zipWith)
 
 -- | Archetype with a single entity.
@@ -83,18 +81,18 @@ lookupComponent e cId w = lookupComponents cId w Map.!? e
 -- | Lookup all components by their `ComponentID`.
 lookupComponents :: forall m a. (Component m a) => ComponentID -> Archetype m -> Map EntityID a
 lookupComponents cId arch = case lookupComponentsAscMaybe cId arch of
-  Just as -> Map.fromAscList $ zip (Set.toList $ entities arch) (V.toList as)
+  Just as -> Map.fromAscList $ zip (Set.toList $ entities arch) as
   Nothing -> Map.empty
 {-# INLINE lookupComponents #-}
 
 -- | Lookup all components by their `ComponentID`, in ascending order by their `EntityID`.
-lookupComponentsAsc :: forall m a. (Component m a) => ComponentID -> Archetype m -> Vector a
-lookupComponentsAsc cId = fromMaybe V.empty . lookupComponentsAscMaybe @m @a cId
+lookupComponentsAsc :: forall m a. (Component m a) => ComponentID -> Archetype m -> [a]
+lookupComponentsAsc cId = fromMaybe [] . lookupComponentsAscMaybe @m @a cId
 {-# INLINE lookupComponentsAsc #-}
 
 -- | Lookup all components by their `ComponentID`, in ascending order by their `EntityID`.
-lookupComponentsAscMaybe :: forall m a. (Component m a) => ComponentID -> Archetype m -> Maybe (Vector a)
-lookupComponentsAscMaybe cId arch = S.toAscVector @a @(StorageT a) <$> lookupStorage @m @a cId arch
+lookupComponentsAscMaybe :: forall m a. (Component m a) => ComponentID -> Archetype m -> Maybe [a]
+lookupComponentsAscMaybe cId arch = S.toAsc @a @(StorageT a) <$> lookupStorage @m @a cId arch
 {-# INLINE lookupComponentsAscMaybe #-}
 
 -- | Insert a component into the archetype.
@@ -104,7 +102,7 @@ insertComponent e cId c arch =
   let oldComponents = lookupComponents @m @a cId arch
       oldValue = oldComponents Map.!? e
       !storage =
-        S.fromAscVector @a @(StorageT a) . V.fromList . Map.elems . Map.insert e c $ oldComponents
+        S.fromAsc @a @(StorageT a) . Map.elems . Map.insert e c $ oldComponents
       hook = case oldValue of
         Just old -> do
           componentOnChange e old c
@@ -119,17 +117,17 @@ insertComponentUntracked ::
   forall m a. (Component m a) => EntityID -> ComponentID -> a -> Archetype m -> Archetype m
 insertComponentUntracked e cId c arch =
   let !storage =
-        S.fromAscVector @a @(StorageT a) . V.fromList . Map.elems . Map.insert e c $ lookupComponents cId arch
+        S.fromAsc @a @(StorageT a) . Map.elems . Map.insert e c $ lookupComponents cId arch
    in arch {storages = IntMap.insert (unComponentId cId) (dynStorage @a storage) (storages arch)}
 
 -- | @True@ if this archetype contains an entity with the provided `ComponentID`.
 member :: ComponentID -> Archetype m -> Bool
 member cId = IntMap.member (unComponentId cId) . storages
 
--- | Zip a vector of components with a function and a component storage.
--- Returns the result vector, updated archetype, and the onChange hooks to run.
+-- | Zip a list of components with a function and a component storage.
+-- Returns the result list, updated archetype, and the onChange hooks to run.
 zipWith ::
-  forall m a c. (Monad m, Component m c) => Vector a -> (a -> c -> c) -> ComponentID -> Archetype m -> (Vector c, Archetype m, Access m ())
+  forall m a c. (Monad m, Component m c) => [a] -> (a -> c -> c) -> ComponentID -> Archetype m -> ([c], Archetype m, Access m ())
 zipWith as f cId arch =
   let oldCs = lookupComponentsAsc @m @c cId arch
       go maybeDyn = case maybeDyn of
@@ -141,15 +139,15 @@ zipWith as f cId arch =
           Nothing -> return maybeDyn
         Nothing -> return Nothing
       (storages', cs) = runWriter $ IntMap.alterF go (unComponentId cId) $ storages arch
-      eIds = V.fromList . Set.toList $ entities arch
-      hooks = V.foldl (\acc (e, old, new) -> acc >> componentOnChange e old new >> triggerEntityEvent e (OnChange old new)) (return ()) (V.zip3 eIds oldCs cs)
+      eIds = Set.toList $ entities arch
+      hooks = foldl (\acc (e, old, new) -> acc >> componentOnChange e old new >> triggerEntityEvent e (OnChange old new)) (return ()) (zip3 eIds oldCs cs)
    in (cs, arch {storages = storages'}, hooks)
 {-# INLINE zipWith #-}
 
--- | Zip a vector of components with a monadic function and a component storage.
--- Returns the result vector, updated archetype, and the onChange hooks to run.
+-- | Zip a list of components with a monadic function and a component storage.
+-- Returns the result list, updated archetype, and the onChange hooks to run.
 zipWithM ::
-  forall m a c. (Monad m, Component m c) => Vector a -> (a -> c -> m c) -> ComponentID -> Archetype m -> m (Vector c, Archetype m, Access m ())
+  forall m a c. (Monad m, Component m c) => [a] -> (a -> c -> m c) -> ComponentID -> Archetype m -> m ([c], Archetype m, Access m ())
 zipWithM as f cId arch = do
   let oldCs = lookupComponentsAsc @m @c cId arch
       go maybeDyn = case maybeDyn of
@@ -163,14 +161,14 @@ zipWithM as f cId arch = do
         Nothing -> pure Nothing
   res <- runWriterT $ IntMap.alterF go (unComponentId cId) $ storages arch
   let cs = snd res
-      eIds = V.fromList . Set.toList $ entities arch
-      hooks = V.foldl (\acc (e, old, new) -> acc >> componentOnChange e old new >> triggerEntityEvent e (OnChange old new)) (return ()) (V.zip3 eIds oldCs cs)
+      eIds = Set.toList $ entities arch
+      hooks = foldl (\acc (e, old, new) -> acc >> componentOnChange e old new >> triggerEntityEvent e (OnChange old new)) (return ()) (zip3 eIds oldCs cs)
   return (cs, arch {storages = fst res}, hooks)
 
--- | Zip a vector of components with a function and a component storage.
+-- | Zip a list of components with a function and a component storage.
 -- Returns the updated archetype and the onChange hooks to run.
 zipWith_ ::
-  forall m a c. (Monad m, Component m c) => Vector a -> (a -> c -> c) -> ComponentID -> Archetype m -> (Archetype m, Access m ())
+  forall m a c. (Monad m, Component m c) => [a] -> (a -> c -> c) -> ComponentID -> Archetype m -> (Archetype m, Access m ())
 zipWith_ as f cId arch =
   let oldCs = lookupComponentsAsc @m @c cId arch
       maybeStorage = case IntMap.lookup (unComponentId cId) $ storages arch of
@@ -181,15 +179,15 @@ zipWith_ as f cId arch =
         Nothing -> Nothing
    in case maybeStorage of
         Just (cs, s) ->
-          let eIds = V.fromList . Set.toList $ entities arch
-              hooks = V.foldl (\acc (e, old, new) -> acc >> componentOnChange e old new >> triggerEntityEvent e (OnChange old new)) (return ()) (V.zip3 eIds oldCs cs)
+          let eIds = Set.toList $ entities arch
+              hooks = foldl (\acc (e, old, new) -> acc >> componentOnChange e old new >> triggerEntityEvent e (OnChange old new)) (return ()) (zip3 eIds oldCs cs)
            in (empty {storages = IntMap.singleton (unComponentId cId) s}, hooks)
         Nothing -> (empty {storages = IntMap.empty}, return ())
 {-# INLINE zipWith_ #-}
 
--- | Zip a vector of components with a function returning a tuple.
+-- | Zip a list of components with a function returning a tuple.
 zipWithAccum ::
-  forall m a c o. (Monad m, Component m c) => Vector a -> (a -> c -> (o, c)) -> ComponentID -> Archetype m -> (Vector (o, c), Archetype m, Access m ())
+  forall m a c o. (Monad m, Component m c) => [a] -> (a -> c -> (o, c)) -> ComponentID -> Archetype m -> ([(o, c)], Archetype m, Access m ())
 zipWithAccum as f cId arch =
   let oldCs = lookupComponentsAsc @m @c cId arch
       go maybeDyn = case maybeDyn of
@@ -201,14 +199,14 @@ zipWithAccum as f cId arch =
           Nothing -> return maybeDyn
         Nothing -> return Nothing
       (storages', pairs) = runWriter $ IntMap.alterF go (unComponentId cId) $ storages arch
-      eIds = V.fromList . Set.toList $ entities arch
-      hooks = V.foldl (\acc (e, old, (_, new)) -> acc >> componentOnChange e old new >> triggerEntityEvent e (OnChange old new)) (return ()) (V.zip3 eIds oldCs pairs)
+      eIds = Set.toList $ entities arch
+      hooks = foldl (\acc (e, old, (_, new)) -> acc >> componentOnChange e old new >> triggerEntityEvent e (OnChange old new)) (return ()) (zip3 eIds oldCs pairs)
    in (pairs, arch {storages = storages'}, hooks)
 {-# INLINE zipWithAccum #-}
 
--- | Zip a vector of components with a monadic function returning a tuple.
+-- | Zip a list of components with a monadic function returning a tuple.
 zipWithAccumM ::
-  forall m a c o. (Monad m, Component m c) => Vector a -> (a -> c -> m (o, c)) -> ComponentID -> Archetype m -> m (Vector (o, c), Archetype m, Access m ())
+  forall m a c o. (Monad m, Component m c) => [a] -> (a -> c -> m (o, c)) -> ComponentID -> Archetype m -> m ([(o, c)], Archetype m, Access m ())
 zipWithAccumM as f cId arch = do
   let oldCs = lookupComponentsAsc @m @c cId arch
       go maybeDyn = case maybeDyn of
@@ -222,25 +220,25 @@ zipWithAccumM as f cId arch = do
         Nothing -> pure Nothing
   res <- runWriterT $ IntMap.alterF go (unComponentId cId) $ storages arch
   let pairs = snd res
-      eIds = V.fromList . Set.toList $ entities arch
-      hooks = V.foldl (\acc (e, old, (_, new)) -> acc >> componentOnChange e old new >> triggerEntityEvent e (OnChange old new)) (return ()) (V.zip3 eIds oldCs pairs)
+      eIds = Set.toList $ entities arch
+      hooks = foldl (\acc (e, old, (_, new)) -> acc >> componentOnChange e old new >> triggerEntityEvent e (OnChange old new)) (return ()) (zip3 eIds oldCs pairs)
   return (pairs, arch {storages = fst res}, hooks)
 {-# INLINE zipWithAccumM #-}
 
--- | Insert a vector of components into the archetype, sorted in ascending order by their `EntityID`.
-insertAscVector :: forall m a. (Component m a) => ComponentID -> Vector a -> Archetype m -> Archetype m
-insertAscVector cId as arch =
-  let !storage = dynStorage @a $ S.fromAscVector @a @(StorageT a) as
+-- | Insert a list of components into the archetype, sorted in ascending order by their `EntityID`.
+insertAscList :: forall m a. (Component m a) => ComponentID -> [a] -> Archetype m -> Archetype m
+insertAscList cId as arch =
+  let !storage = dynStorage @a $ S.fromAsc @a @(StorageT a) as
    in arch {storages = IntMap.insert (unComponentId cId) storage $ storages arch}
-{-# INLINE insertAscVector #-}
+{-# INLINE insertAscList #-}
 
 -- | Remove an entity from an archetype, returning its components.
 remove :: EntityID -> Archetype m -> (IntMap Dynamic, Archetype m)
 remove e arch =
   let go (dynAcc, archAcc) (cId, dynS) =
-        let cs = Map.fromAscList . zip (Set.toList $ entities arch) . V.toList $ toAscVectorDyn dynS
+        let cs = Map.fromAscList . zip (Set.toList $ entities arch) $ toAscListDyn dynS
             !(dynA, cs') = Map.updateLookupWithKey (\_ _ -> Nothing) e cs
-            dynS' = S.fromAscVectorDyn (V.fromList $ Map.elems cs') dynS
+            dynS' = S.fromAscListDyn (Map.elems cs') dynS
             !dynAcc' = case dynA of
               Just d -> IntMap.insert cId d dynAcc
               Nothing -> dynAcc
@@ -252,9 +250,9 @@ remove e arch =
 removeStorages :: EntityID -> Archetype m -> (IntMap DynamicStorage, Archetype m)
 removeStorages e arch =
   let go (dynAcc, archAcc) (cId, dynS) =
-        let cs = Map.fromAscList . zip (Set.toList $ entities arch) . V.toList $ toAscVectorDyn dynS
+        let cs = Map.fromAscList . zip (Set.toList $ entities arch) $ toAscListDyn dynS
             !(dynA, cs') = Map.updateLookupWithKey (\_ _ -> Nothing) e cs
-            dynS' = S.fromAscVectorDyn (V.fromList $ Map.elems cs') dynS
+            dynS' = S.fromAscListDyn (Map.elems cs') dynS
             !dynAcc' = case dynA of
               Just d -> IntMap.insert cId (S.singletonDyn d dynS') dynAcc
               Nothing -> dynAcc
@@ -269,7 +267,7 @@ insertComponents e cs arch =
         let storages' = IntMap.adjust go itemCId (storages archAcc)
             es = Set.toList $ entities archAcc
             go s =
-              let ecs = V.fromList . Map.elems . Map.insert e dyn . Map.fromAscList . zip es . V.toList $ toAscVectorDyn s
-               in fromAscVectorDyn ecs s
+              let ecs = Map.elems . Map.insert e dyn . Map.fromAscList . zip es $ toAscListDyn s
+               in fromAscListDyn ecs s
          in archAcc {storages = storages', entities = Set.insert e $ entities archAcc}
    in foldl' f arch (IntMap.toList cs)
diff --git a/src/Aztecs/ECS/World/Archetypes.hs b/src/Aztecs/ECS/World/Archetypes.hs
index 93750373..ba9c6042 100644
--- a/src/Aztecs/ECS/World/Archetypes.hs
+++ b/src/Aztecs/ECS/World/Archetypes.hs
@@ -44,7 +44,6 @@ import qualified Data.Map.Strict as Map
 import Data.Maybe
 import Data.Set (Set)
 import qualified Data.Set as Set
-import qualified Data.Vector.Strict as V
 import Prelude hiding (all, lookup, map)
 
 -- | Empty `Archetypes`.
@@ -174,7 +173,7 @@ remove e aId cId arches = case lookup aId arches of
           !arches' = arches {nodes = Map.insert aId node {nodeArchetype = arch'} (nodes arches)}
           (a, cs') = IntMap.updateLookupWithKey (\_ _ -> Nothing) (unComponentId cId) cs
           go' archAcc (itemCId, dyn) =
-            let adjustStorage s = fromAscVectorDyn (V.fromList . Map.elems . Map.insert e dyn . Map.fromAscList . zip (Set.toList $ entities archAcc) . V.toList $ toAscVectorDyn s) s
+            let adjustStorage s = fromAscListDyn (Map.elems . Map.insert e dyn . Map.fromAscList . zip (Set.toList $ entities archAcc) $ toAscListDyn s) s
              in archAcc {storages = IntMap.adjust adjustStorage itemCId (storages archAcc)}
           go nextNode =
             nextNode {nodeArchetype = foldl' go' (nodeArchetype nextNode) (IntMap.toList cs')}
@@ -195,7 +194,7 @@ remove e aId cId arches = case lookup aId arches of
               }
           !(nextAId, arches') = insertArchetype destCIds n arches
           node' = node {nodeArchetype = arch'}
-          maybeA = a >>= (\dynS -> V.headM (toAscVectorDyn dynS) >>= fromDynamic)
+          maybeA = a >>= (\dynS -> listToMaybe (toAscListDyn dynS) >>= fromDynamic)
           hook = maybe (return ()) (\comp -> componentOnRemove e comp >> triggerEntityEvent e (OnRemove comp)) maybeA
        in ( (,nextAId) <$> maybeA,
             arches' {nodes = Map.insert aId node' (nodes arches')},
diff --git a/src/Aztecs/ECS/World/Storage.hs b/src/Aztecs/ECS/World/Storage.hs
index aba8f54b..ff026a25 100644
--- a/src/Aztecs/ECS/World/Storage.hs
+++ b/src/Aztecs/ECS/World/Storage.hs
@@ -11,9 +11,9 @@
 -- Portability : non-portable (GHC extensions)
 module Aztecs.ECS.World.Storage (Storage (..)) where
 
+import Control.Monad (zipWithM)
 import Data.Data
-import Data.Vector.Strict (Vector)
-import qualified Data.Vector.Strict as V
+import qualified Data.List as L
 import Prelude hiding (map, zipWith)
 
 -- | Component storage, containing zero or many components of the same type.
@@ -21,61 +21,61 @@ class (Typeable s, Typeable a) => Storage a s where
   -- | Storage with a single component.
   singleton :: a -> s
 
-  -- | Vector of all components in the storage in ascending order.
-  toAscVector :: s -> Vector a
+  -- | List of all components in the storage in ascending order.
+  toAsc :: s -> [a]
 
-  -- | Convert a sorted vector of components (in ascending order) into a storage.
-  fromAscVector :: Vector a -> s
+  -- | Convert a sorted list of components (in ascending order) into a storage.
+  fromAsc :: [a] -> s
 
   -- | Map a function over all components in the storage.
   map :: (a -> a) -> s -> s
 
   -- | Map a function with some input over all components in the storage.
-  zipWith :: (i -> a -> a) -> Vector i -> s -> (Vector a, s)
+  zipWith :: (i -> a -> a) -> [i] -> s -> ([a], s)
 
   -- | Map an applicative functor with some input over all components in the storage.
-  zipWithM :: (Monad m) => (i -> a -> m a) -> Vector i -> s -> m (Vector a, s)
+  zipWithM :: (Monad m) => (i -> a -> m a) -> [i] -> s -> m ([a], s)
 
   -- | Map a function with some input over all components in the storage.
-  zipWith_ :: (i -> a -> a) -> Vector i -> s -> s
+  zipWith_ :: (i -> a -> a) -> [i] -> s -> s
   zipWith_ f is as = snd $ zipWith f is as
 
   -- | Map a function with some input over all components, returning a tuple result and updated storage.
-  zipWithAccum :: (i -> a -> (o, a)) -> Vector i -> s -> (Vector (o, a), s)
+  zipWithAccum :: (i -> a -> (o, a)) -> [i] -> s -> ([(o, a)], s)
 
   -- | Map a monadic function with some input over all components, returning a tuple result and updated storage.
-  zipWithAccumM :: (Monad m) => (i -> a -> m (o, a)) -> Vector i -> s -> m (Vector (o, a), s)
+  zipWithAccumM :: (Monad m) => (i -> a -> m (o, a)) -> [i] -> s -> m ([(o, a)], s)
 
-instance (Typeable a) => Storage a (Vector a) where
-  singleton a = V.singleton a
+instance (Typeable a) => Storage a [a] where
+  singleton a = [a]
   {-# INLINE singleton #-}
 
-  toAscVector = id
-  {-# INLINE toAscVector #-}
+  toAsc = id
+  {-# INLINE toAsc #-}
 
-  fromAscVector = id
-  {-# INLINE fromAscVector #-}
+  fromAsc = id
+  {-# INLINE fromAsc #-}
 
-  map = V.map
+  map = fmap
   {-# INLINE map #-}
 
-  zipWith f is as = let as' = V.zipWith f is as in (as', as')
+  zipWith f is as = let as' = L.zipWith f is as in (as', as')
   {-# INLINE zipWith #-}
 
-  zipWith_ f is as = V.zipWith f is as
+  zipWith_ f is as = L.zipWith f is as
   {-# INLINE zipWith_ #-}
 
-  zipWithM f is as = (\as' -> (as', as')) <$> V.zipWithM f is as
+  zipWithM f is as = (\as' -> (as', as')) <$> Control.Monad.zipWithM f is as
   {-# INLINE zipWithM #-}
 
   zipWithAccum f is as =
-    let pairs = V.zipWith f is as
-        as' = V.map snd pairs
+    let pairs = L.zipWith f is as
+        as' = fmap snd pairs
      in (pairs, as')
   {-# INLINE zipWithAccum #-}
 
   zipWithAccumM f is as = do
-    pairs <- V.zipWithM f is as
-    let as' = V.map snd pairs
+    pairs <- Control.Monad.zipWithM f is as
+    let as' = fmap snd pairs
     return (pairs, as')
   {-# INLINE zipWithAccumM #-}
diff --git a/src/Aztecs/ECS/World/Storage/Dynamic.hs b/src/Aztecs/ECS/World/Storage/Dynamic.hs
index 253474fe..d78c2601 100644
--- a/src/Aztecs/ECS/World/Storage/Dynamic.hs
+++ b/src/Aztecs/ECS/World/Storage/Dynamic.hs
@@ -20,16 +20,14 @@ module Aztecs.ECS.World.Storage.Dynamic
   ( DynamicStorage (..),
     dynStorage,
     singletonDyn,
-    fromAscVectorDyn,
-    toAscVectorDyn,
+    fromAscListDyn,
+    toAscListDyn,
   )
 where
 
 import qualified Aztecs.ECS.World.Storage as S
 import Data.Dynamic
 import Data.Maybe
-import Data.Vector.Strict (Vector)
-import qualified Data.Vector.Strict as V
 
 -- | Dynamic storage of components.
 data DynamicStorage = DynamicStorage
@@ -37,10 +35,10 @@ data DynamicStorage = DynamicStorage
     storageDyn :: !Dynamic,
     -- | Singleton storage.
     singletonDyn' :: !(Dynamic -> Dynamic),
-    -- | Convert this storage to an ascending vector.
-    toAscVectorDyn' :: !(Dynamic -> Vector Dynamic),
-    -- | Convert from an ascending vector.
-    fromAscVectorDyn' :: !(Vector Dynamic -> Dynamic)
+    -- | Convert this storage to an ascending list.
+    toAscListDyn' :: !(Dynamic -> [Dynamic]),
+    -- | Convert from an ascending list.
+    fromAscListDyn' :: !([Dynamic] -> Dynamic)
   }
 
 instance Show DynamicStorage where
@@ -52,8 +50,8 @@ dynStorage s =
   DynamicStorage
     { storageDyn = toDyn s,
       singletonDyn' = toDyn . S.singleton @a @s . fromMaybe (error "TODO") . fromDynamic,
-      toAscVectorDyn' = \d -> V.map toDyn (S.toAscVector @a @s (fromMaybe (error "TODO") $ fromDynamic d)),
-      fromAscVectorDyn' = toDyn . S.fromAscVector @a @s . V.map (fromMaybe (error "TODO") . fromDynamic)
+      toAscListDyn' = \d -> fmap toDyn (S.toAsc @a @s (fromMaybe (error "TODO") $ fromDynamic d)),
+      fromAscListDyn' = toDyn . S.fromAsc @a @s . fmap (fromMaybe (error "TODO") . fromDynamic)
     }
 {-# INLINE dynStorage #-}
 
@@ -61,10 +59,10 @@ dynStorage s =
 singletonDyn :: Dynamic -> DynamicStorage -> DynamicStorage
 singletonDyn dyn s = s {storageDyn = singletonDyn' s dyn}
 
--- | Convert from an ascending vector.
-fromAscVectorDyn :: Vector Dynamic -> DynamicStorage -> DynamicStorage
-fromAscVectorDyn dyns s = s {storageDyn = fromAscVectorDyn' s dyns}
+-- | Convert from an ascending list.
+fromAscListDyn :: [Dynamic] -> DynamicStorage -> DynamicStorage
+fromAscListDyn dyns s = s {storageDyn = fromAscListDyn' s dyns}
 
--- | Convert this storage to an ascending vector.
-toAscVectorDyn :: DynamicStorage -> Vector Dynamic
-toAscVectorDyn = toAscVectorDyn' <*> storageDyn
+-- | Convert this storage to an ascending list.
+toAscListDyn :: DynamicStorage -> [Dynamic]
+toAscListDyn = toAscListDyn' <*> storageDyn
diff --git a/src/Aztecs/Hierarchy.hs b/src/Aztecs/Hierarchy.hs
index b22adbdd..8190207c 100644
--- a/src/Aztecs/Hierarchy.hs
+++ b/src/Aztecs/Hierarchy.hs
@@ -44,8 +44,6 @@ import qualified Data.Map as Map
 import Data.Maybe
 import Data.Set (Set)
 import qualified Data.Set as Set
-import Data.Vector.Strict (Vector)
-import qualified Data.Vector.Strict as V
 import GHC.Generics
 
 -- | Parent component.
@@ -120,9 +118,9 @@ instance Traversable Hierarchy where
   traverse f n =
     Node (nodeEntityId n) <$> f (nodeEntity n) <*> traverse (traverse f) (nodeChildren n)
 
--- | Convert a hierarchy to a vector of entity IDs and components.
-toList :: Hierarchy a -> Vector (EntityID, a)
-toList n = V.singleton (nodeEntityId n, nodeEntity n) <> V.concatMap toList (V.fromList $ nodeChildren n)
+-- | Convert a hierarchy to a list of entity IDs and components.
+toList :: Hierarchy a -> [(EntityID, a)]
+toList n = (nodeEntityId n, nodeEntity n) : concatMap toList (nodeChildren n)
 
 -- | Fold a hierarchy with a function that takes the entity ID, entity, and accumulator.
 foldWithKey :: (EntityID -> a -> b -> b) -> Hierarchy a -> b -> b
@@ -153,7 +151,7 @@ hierarchy e q = do
         a' <- q
         return $ liftA3 (\eid c a'' -> (eid, (unChildren c, a''))) e' cs a'
   children <- A.system $ S.readQuery mkQuery
-  let childMap = Map.fromList $ V.toList children
+  let childMap = Map.fromList children
   return $ hierarchy' e childMap
 
 -- | Build all hierarchies of parents to children, joined with the given query.
@@ -161,7 +159,7 @@ hierarchies ::
   forall m a.
   (Monad m) =>
   (forall f. (Applicative f) => Query f m (f a)) ->
-  Access m (Vector (Hierarchy a))
+  Access m [Hierarchy a]
 hierarchies q = do
   let mkQuery :: forall f. (Applicative f) => Query f m (f (EntityID, (Set EntityID, a)))
       mkQuery = do
@@ -170,9 +168,9 @@ hierarchies q = do
         a' <- q
         return $ liftA3 (\eid c a -> (eid, (unChildren c, a))) e' cs a'
   children <- A.system $ S.readQuery mkQuery
-  let childMap = Map.fromList $ V.toList children
+  let childMap = Map.fromList children
   roots <- A.system $ S.readQueryFiltered (Q.entity) (with @m @Children <> without @m @Parent)
-  return $ V.mapMaybe (`hierarchy'` childMap) roots
+  return $ mapMaybe (`hierarchy'` childMap) roots
 
 -- | Build a hierarchy of parents to children.
 hierarchy' :: EntityID -> Map EntityID (Set EntityID, a) -> Maybe (Hierarchy a)
diff --git a/test/Main.hs b/test/Main.hs
index be1ac85d..fe95ad88 100644
--- a/test/Main.hs
+++ b/test/Main.hs
@@ -17,7 +17,6 @@ import qualified Aztecs.ECS.Query as Q
 import qualified Aztecs.ECS.World as W
 import Control.Applicative
 import Data.Functor.Identity
-import qualified Data.Vector.Strict as V
 import Data.Word
 import GHC.Generics
 import Test.Hspec
@@ -63,7 +62,7 @@ prop_queryEmpty =
           . runIdentity
           . Q.readQuery (Q.query @_ @_ @X)
           $ W.entities W.empty
-   in V.toList res `shouldMatchList` []
+   in res `shouldMatchList` []
 
 -- | Query all components from a list of `ComponentID`s.
 queryComponentIds ::
@@ -99,14 +98,14 @@ prop_queryDyn xs =
       (es, w) = foldr spawner ([], W.empty) xs
       go (e, cs) = do
         let (res, _) = runIdentity . Q.readQuery (queryComponentIds @X @Identity $ map snd cs) $ W.entities w
-        return $ V.toList res `shouldContain` [(e, map fst cs)]
+        return $ res `shouldContain` [(e, map fst cs)]
    in mapM_ go es
 
 prop_queryTypedComponent :: [X] -> Expectation
 prop_queryTypedComponent xs = do
   let w = foldr (\x -> (\(_, w', _) -> w') . W.spawn (bundle x)) W.empty xs
       (res, _) = runIdentity . Q.readQuery (Q.query @_ @_ @X) $ W.entities w
-  V.toList res `shouldMatchList` xs
+  res `shouldMatchList` xs
 
 prop_queryTwoTypedComponents :: [(X, Y)] -> Expectation
 prop_queryTwoTypedComponents xys = do
@@ -120,7 +119,7 @@ prop_queryTwoTypedComponents xys = do
                 return $ liftA2 (,) x y
             )
           $ W.entities w
-  V.toList res `shouldMatchList` xys
+  res `shouldMatchList` xys
 
 prop_queryThreeTypedComponents :: [(X, Y, Z)] -> Expectation
 prop_queryThreeTypedComponents xyzs = do
@@ -135,7 +134,7 @@ prop_queryThreeTypedComponents xyzs = do
                 return $ liftA3 (,,) x y z
             )
           $ W.entities w
-  V.toList res `shouldMatchList` xyzs
+  res `shouldMatchList` xyzs
 
 prop_querySingle :: Expectation
 prop_querySingle =

From f71bb109be00710a766c68cf032b745a30766c62 Mon Sep 17 00:00:00 2001
From: Matt Hunzinger <matt@hunzinger.me>
Date: Wed, 28 Jan 2026 22:50:39 -0500
Subject: [PATCH 3/6] feat: alterStorageF

---
 src/Aztecs/ECS/Query.hs           | 76 +++++++++++++++----------------
 src/Aztecs/ECS/World/Archetype.hs | 65 +++++++++++++++++++++++++-
 2 files changed, 101 insertions(+), 40 deletions(-)

diff --git a/src/Aztecs/ECS/Query.hs b/src/Aztecs/ECS/Query.hs
index a87fb0d9..546c4637 100644
--- a/src/Aztecs/ECS/Query.hs
+++ b/src/Aztecs/ECS/Query.hs
@@ -58,9 +58,9 @@ module Aztecs.ECS.Query
   )
 where
 
-import Aztecs.ECS.Access.Internal (Access)
+import Aztecs.ECS.Access.Internal
 import Aztecs.ECS.Component
-import Aztecs.ECS.Entity (EntityID)
+import Aztecs.ECS.Entity
 import Aztecs.ECS.Query.Dynamic hiding (entity, queryDyn)
 import qualified Aztecs.ECS.Query.Dynamic as DQ
 import Aztecs.ECS.World.Archetype (Archetype)
@@ -75,7 +75,7 @@ import Control.Monad.Reader
 import Control.Monad.State
 import Data.Set (Set)
 import qualified Data.Set as Set
-import GHC.Stack (HasCallStack)
+import GHC.Stack
 import Prelude hiding (reads)
 
 -- | A list with zip semantics for @Applicative@.
@@ -94,16 +94,16 @@ data Op f m a where
   QueryMapOp :: (Component m a) => ComponentID -> (f a -> f a) -> Op f m (f a)
   QueryMapAccumOp :: (Component m b) => ComponentID -> (f b -> f (a, b)) -> Op f m (f (a, b))
 
-newtype QueryBuilder f m a = QueryBuilder {unQueryBuilder :: Free (Ap (Op f m)) a}
+newtype QueryPlan f m a = QueryPlan {unQueryPlan :: Free (Ap (Op f m)) a}
   deriving (Functor, Applicative, Monad)
 
 -- | Query for matching entities.
-newtype Query f m a = Query {unQuery :: ReaderT Components (QueryBuilder f m) a}
+newtype Query f m a = Query {unQuery :: ReaderT Components (QueryPlan f m) a}
   deriving (Functor, Applicative, Monad)
 
 -- | Query the entity ID.
 entity :: forall f m. (Applicative f) => Query f m (f EntityID)
-entity = Query . lift . QueryBuilder . liftF . liftAp $ EntityOp
+entity = Query . lift . QueryPlan . liftF . liftAp $ EntityOp
 {-# INLINE entity #-}
 
 -- | Query a component.
@@ -111,7 +111,7 @@ query :: forall f m a. (Applicative f, Component m a) => Query f m (f a)
 query = Query $ do
   cs <- ask
   let !(cId, _) = CS.insert @a @m cs
-  lift . QueryBuilder . liftF . liftAp $ QueryOp cId
+  lift . QueryPlan . liftF . liftAp $ QueryOp cId
 {-# INLINE query #-}
 
 -- | Query a component and update it.
@@ -119,7 +119,7 @@ queryMap :: forall f m a. (Applicative f, Component m a) => (f a -> f a) -> Quer
 queryMap f = Query $ do
   cs <- ask
   let !(cId, _) = CS.insert @a @m cs
-  lift . QueryBuilder . liftF . liftAp $ QueryMapOp cId f
+  lift . QueryPlan . liftF . liftAp $ QueryMapOp cId f
 {-# INLINE queryMap #-}
 
 -- | Query a component with input, returning a tuple of the result and the updated component.
@@ -127,71 +127,69 @@ queryMapAccum :: forall f m a b. (Applicative f, Component m b) => (f b -> f (a,
 queryMapAccum f = Query $ do
   cs <- ask
   let !(cId, _) = CS.insert @b @m cs
-  lift . QueryBuilder . liftF . liftAp $ QueryMapAccumOp cId f
+  lift . QueryPlan . liftF . liftAp $ QueryMapAccumOp cId f
 {-# INLINE queryMapAccum #-}
 
 newtype Fetch a = Fetch (Const () a)
   deriving (Functor, Applicative)
 
-buildQueryBuilder :: (Monad m) => QueryBuilder QueryStream m (QueryStream a) -> DynamicQuery m a
-buildQueryBuilder a = DynamicQuery $ \arch -> do
-  (as, (arch', hooks)) <- runStateT (foldFree (runAp go) $ unQueryBuilder a) (arch, pure ())
+buildQueryPlan :: (Monad m) => QueryPlan QueryStream m (QueryStream a) -> DynamicQuery m a
+buildQueryPlan a = DynamicQuery $ \arch -> do
+  (as, (arch', hooks)) <- runStateT (foldFree (runAp go) $ unQueryPlan a) (arch, pure ())
   return (unQueryStream as, arch', hooks)
   where
     go :: (Monad m) => Op QueryStream m x -> StateT (Archetype m, Access m ()) m x
     go = \case
       EntityOp -> goEntity
-      QueryOp cId -> goRead cId
-      QueryMapOp cId f -> goWrite cId f
+      QueryOp cId -> goQuery cId
+      QueryMapOp cId f -> goMap cId f
       QueryMapAccumOp cId f -> goMapAccum cId f
     goEntity :: (Monad m) => StateT (Archetype m, Access m ()) m (QueryStream EntityID)
     goEntity = do
       (arch, _) <- get
       return $ QueryStream $ Set.toList $ A.entities arch
-    goRead :: forall m a. (Monad m, Component m a) => ComponentID -> StateT (Archetype m, Access m ()) m (QueryStream a)
-    goRead cId = do
+    goQuery :: forall m a. (Monad m, Component m a) => ComponentID -> StateT (Archetype m, Access m ()) m (QueryStream a)
+    goQuery cId = do
       (arch, hooks) <- get
       (as, arch', hooks') <- lift $ runDynQuery (DQ.queryDyn cId) arch
       put (arch', hooks >> hooks')
       return (QueryStream as)
-    goWrite :: forall m a. (Monad m, Component m a) => ComponentID -> (QueryStream a -> QueryStream a) -> StateT (Archetype m, Access m ()) m (QueryStream a)
-    goWrite cId f = do
+    goMap :: forall m a. (Monad m, Component m a) => ComponentID -> (QueryStream a -> QueryStream a) -> StateT (Archetype m, Access m ()) m (QueryStream a)
+    goMap cId f = do
       (arch, hooks) <- get
-      let as = A.lookupComponentsAsc cId arch
-          as' = unQueryStream $ f (QueryStream as)
-          arch' = A.insertAscList cId as' arch
+      let (arch', as') = A.alterComponentsAsc (unQueryStream . f . QueryStream) cId arch
       put (arch', hooks)
       return (QueryStream as')
     goMapAccum :: forall m a b. (Monad m, Component m b) => ComponentID -> (QueryStream b -> QueryStream (a, b)) -> StateT (Archetype m, Access m ()) m (QueryStream (a, b))
     goMapAccum cId f = do
       (arch, hooks) <- get
-      let bs = A.lookupComponentsAsc cId arch
-          xs = unQueryStream $ f (QueryStream bs)
-          arch' = A.insertAscList cId (fmap snd xs) arch
+      let f' = fmap (\(a', b) -> (b, (a', b))) . unQueryStream . f . QueryStream
+          (arch', xs) = A.zipAlterComponentsAsc f' cId arch
       put (arch', hooks)
       return (QueryStream xs)
 
 runQuery' :: (Monad m) => (forall f. (Applicative f) => Query f m (f a)) -> Components -> (ReadsWrites, Components, DynamicQuery m a)
-runQuery' qb cs =
-  let actionFetch = runReaderT (unQuery qb) cs
-      (_, rws) = runState (foldFree (runAp go) (unQueryBuilder actionFetch)) mempty
-   in (rws, cs, buildQueryBuilder $ runReaderT (unQuery qb) cs)
+runQuery' q cs =
+  let actionFetch = runReaderT (unQuery q) cs
+      (_, rws) = runState (foldFree (runAp go) (unQueryPlan actionFetch)) mempty
+   in (rws, cs, buildQueryPlan $ runReaderT (unQuery q) cs)
   where
     go :: Op Fetch m x -> State ReadsWrites x
-    go EntityOp = return (Fetch (Const ()))
-    go (QueryOp cId) = do
-      modify (\rws -> rws {reads = Set.insert cId (reads rws)})
-      return (Fetch (Const ()))
-    go (QueryMapOp cId _) = do
-      modify (\rws -> rws {writes = Set.insert cId (writes rws)})
-      return (Fetch (Const ()))
-    go (QueryMapAccumOp cId _) = do
-      modify (\rws -> rws {writes = Set.insert cId (writes rws)})
-      return (Fetch (Const ()))
+    go = \case
+      EntityOp -> return (Fetch (Const ()))
+      (QueryOp cId) -> do
+        modify (\rws -> rws {reads = Set.insert cId (reads rws)})
+        return (Fetch (Const ()))
+      (QueryMapOp cId _) -> do
+        modify (\rws -> rws {writes = Set.insert cId (writes rws)})
+        return (Fetch (Const ()))
+      (QueryMapAccumOp cId _) -> do
+        modify (\rws -> rws {writes = Set.insert cId (writes rws)})
+        return (Fetch (Const ()))
 
 -- | Query a component dynamically by 'ComponentID'.
 queryDyn :: forall f m a. (Applicative f, Component m a, Monad m) => ComponentID -> Query f m (f a)
-queryDyn cId = Query . lift . QueryBuilder . liftF . liftAp $ QueryOp cId
+queryDyn cId = Query . lift . QueryPlan . liftF . liftAp $ QueryOp cId
 {-# INLINE queryDyn #-}
 
 -- | Read all matching entities.
diff --git a/src/Aztecs/ECS/World/Archetype.hs b/src/Aztecs/ECS/World/Archetype.hs
index 57acbea4..479cd785 100644
--- a/src/Aztecs/ECS/World/Archetype.hs
+++ b/src/Aztecs/ECS/World/Archetype.hs
@@ -28,6 +28,10 @@ module Aztecs.ECS.World.Archetype
     lookupComponentsAsc,
     lookupComponentsAscMaybe,
     lookupStorage,
+    alterStorage,
+    alterStorageF,
+    alterComponentsAsc,
+    zipAlterComponentsAsc,
     member,
     remove,
     removeStorages,
@@ -51,6 +55,7 @@ import Aztecs.ECS.World.Archetype.Internal
 import qualified Aztecs.ECS.World.Storage as S
 import Aztecs.ECS.World.Storage.Dynamic
 import qualified Aztecs.ECS.World.Storage.Dynamic as S
+import Control.Monad.Identity
 import Control.Monad.Writer
 import Data.Dynamic
 import Data.Foldable
@@ -73,6 +78,27 @@ lookupStorage cId w = do
   fromDynamic $ storageDyn dynS
 {-# INLINE lookupStorage #-}
 
+-- | Alter a component `Storage` by its `ComponentID`.
+alterStorage :: forall m a. (Component m a) => (StorageT a -> (StorageT a)) -> ComponentID -> Archetype m -> (Archetype m)
+alterStorage f cId w = runIdentity $ alterStorageF @_ @m @a (return . f) cId w
+{-# INLINE alterStorage #-}
+
+-- | Alter a component `Storage` by its `ComponentID`.
+alterStorageF :: forall f m a. (Monad f, Component m a) => (StorageT a -> f (StorageT a)) -> ComponentID -> Archetype m -> f (Archetype m)
+alterStorageF f cId w =
+  (\s -> w {storages = s}) <$> IntMap.alterF go (unComponentId cId) (storages w)
+  where
+    go dyn = case dyn of
+      Just d -> case fromDynamic $ storageDyn d of
+        Just s -> do
+          s' <- f s
+          return $ Just $ d {storageDyn = toDyn s'}
+        Nothing -> return dyn
+      Nothing -> do
+        s' <- f (S.fromAsc @a @(StorageT a) [])
+        return $ Just $ dynStorage @a s'
+{-# INLINE alterStorageF #-}
+
 -- | Lookup a component by its `EntityID` and `ComponentID`.
 lookupComponent :: forall m a. (Component m a) => EntityID -> ComponentID -> Archetype m -> Maybe a
 lookupComponent e cId w = lookupComponents cId w Map.!? e
@@ -95,6 +121,37 @@ lookupComponentsAscMaybe :: forall m a. (Component m a) => ComponentID -> Archet
 lookupComponentsAscMaybe cId arch = S.toAsc @a @(StorageT a) <$> lookupStorage @m @a cId arch
 {-# INLINE lookupComponentsAscMaybe #-}
 
+alterComponentsAsc ::
+  forall m a.
+  (Component m a) =>
+  ([a] -> [a]) ->
+  ComponentID ->
+  Archetype m ->
+  (Archetype m, [a])
+alterComponentsAsc f cId arch = runWriter $ alterStorageF @_ @m @a go cId arch
+  where
+    go s = do
+      let as' = f $ S.toAsc @a @(StorageT a) s
+      tell as'
+      return $ S.fromAsc @a @(StorageT a) as'
+{-# INLINE alterComponentsAsc #-}
+
+zipAlterComponentsAsc ::
+  forall m a b.
+  (Component m a) =>
+  ([a] -> [(a, b)]) ->
+  ComponentID ->
+  Archetype m ->
+  (Archetype m, [b])
+zipAlterComponentsAsc f cId arch = runWriter $ alterStorageF @_ @m @a go cId arch
+  where
+    go s = do
+      let xs = f $ S.toAsc @a @(StorageT a) s
+          (as', bs) = unzip xs
+      tell bs
+      return $ S.fromAsc @a @(StorageT a) as'
+{-# INLINE zipAlterComponentsAsc #-}
+
 -- | Insert a component into the archetype.
 insertComponent ::
   forall m a. (Component m a) => EntityID -> ComponentID -> a -> Archetype m -> (Archetype m, Access m ())
@@ -127,7 +184,13 @@ member cId = IntMap.member (unComponentId cId) . storages
 -- | Zip a list of components with a function and a component storage.
 -- Returns the result list, updated archetype, and the onChange hooks to run.
 zipWith ::
-  forall m a c. (Monad m, Component m c) => [a] -> (a -> c -> c) -> ComponentID -> Archetype m -> ([c], Archetype m, Access m ())
+  forall m a c.
+  (Monad m, Component m c) =>
+  [a] ->
+  (a -> c -> c) ->
+  ComponentID ->
+  Archetype m ->
+  ([c], Archetype m, Access m ())
 zipWith as f cId arch =
   let oldCs = lookupComponentsAsc @m @c cId arch
       go maybeDyn = case maybeDyn of

From 0e82c7760969f68acf50ee705d423d225ba6edec Mon Sep 17 00:00:00 2001
From: Matt Hunzinger <matt@hunzinger.me>
Date: Wed, 28 Jan 2026 22:57:23 -0500
Subject: [PATCH 4/6] refactor: simplify

---
 src/Aztecs/ECS/Query.hs | 97 +++++++++++++++++++++--------------------
 test/Main.hs            | 15 +++----
 2 files changed, 57 insertions(+), 55 deletions(-)

diff --git a/src/Aztecs/ECS/Query.hs b/src/Aztecs/ECS/Query.hs
index 546c4637..ad1934d4 100644
--- a/src/Aztecs/ECS/Query.hs
+++ b/src/Aztecs/ECS/Query.hs
@@ -140,33 +140,25 @@ buildQueryPlan a = DynamicQuery $ \arch -> do
   where
     go :: (Monad m) => Op QueryStream m x -> StateT (Archetype m, Access m ()) m x
     go = \case
-      EntityOp -> goEntity
-      QueryOp cId -> goQuery cId
-      QueryMapOp cId f -> goMap cId f
-      QueryMapAccumOp cId f -> goMapAccum cId f
-    goEntity :: (Monad m) => StateT (Archetype m, Access m ()) m (QueryStream EntityID)
-    goEntity = do
-      (arch, _) <- get
-      return $ QueryStream $ Set.toList $ A.entities arch
-    goQuery :: forall m a. (Monad m, Component m a) => ComponentID -> StateT (Archetype m, Access m ()) m (QueryStream a)
-    goQuery cId = do
-      (arch, hooks) <- get
-      (as, arch', hooks') <- lift $ runDynQuery (DQ.queryDyn cId) arch
-      put (arch', hooks >> hooks')
-      return (QueryStream as)
-    goMap :: forall m a. (Monad m, Component m a) => ComponentID -> (QueryStream a -> QueryStream a) -> StateT (Archetype m, Access m ()) m (QueryStream a)
-    goMap cId f = do
-      (arch, hooks) <- get
-      let (arch', as') = A.alterComponentsAsc (unQueryStream . f . QueryStream) cId arch
-      put (arch', hooks)
-      return (QueryStream as')
-    goMapAccum :: forall m a b. (Monad m, Component m b) => ComponentID -> (QueryStream b -> QueryStream (a, b)) -> StateT (Archetype m, Access m ()) m (QueryStream (a, b))
-    goMapAccum cId f = do
-      (arch, hooks) <- get
-      let f' = fmap (\(a', b) -> (b, (a', b))) . unQueryStream . f . QueryStream
-          (arch', xs) = A.zipAlterComponentsAsc f' cId arch
-      put (arch', hooks)
-      return (QueryStream xs)
+      EntityOp -> do
+        (arch, _) <- get
+        return $ QueryStream $ Set.toList $ A.entities arch
+      QueryOp cId -> do
+        (arch, hooks) <- get
+        (as, arch', hooks') <- lift $ runDynQuery (DQ.queryDyn cId) arch
+        put (arch', hooks >> hooks')
+        return (QueryStream as)
+      QueryMapOp cId f -> do
+        (arch, hooks) <- get
+        let (arch', as') = A.alterComponentsAsc (unQueryStream . f . QueryStream) cId arch
+        put (arch', hooks)
+        return (QueryStream as')
+      QueryMapAccumOp cId f -> do
+        (arch, hooks) <- get
+        let f' = fmap (\(a', b) -> (b, (a', b))) . unQueryStream . f . QueryStream
+            (arch', xs) = A.zipAlterComponentsAsc f' cId arch
+        put (arch', hooks)
+        return (QueryStream xs)
 
 runQuery' :: (Monad m) => (forall f. (Applicative f) => Query f m (f a)) -> Components -> (ReadsWrites, Components, DynamicQuery m a)
 runQuery' q cs =
@@ -193,37 +185,48 @@ queryDyn cId = Query . lift . QueryPlan . liftF . liftAp $ QueryOp cId
 {-# INLINE queryDyn #-}
 
 -- | Read all matching entities.
-readQuery :: (Monad m) => (forall f. (Applicative f) => Query f m (f a)) -> Entities m -> m ([a], Entities m)
-readQuery q es =
-  let (rws, cs', dynQ) = runQuery' q (components es)
-   in do
-        res <- DQ.readQueryDyn (reads rws <> writes rws) dynQ es
-        return (res, es {components = cs'})
+readQuery :: (Monad m) => (forall f. (Applicative f) => Query f m (f a)) -> Entities m -> m [a]
+readQuery = runner readQueryDyn
 {-# INLINE readQuery #-}
 
 -- | Read a single matching entity.
-readQuerySingle :: (HasCallStack, Monad m) => (forall f. (Applicative f) => Query f m (f a)) -> Entities m -> m (a, Entities m)
-readQuerySingle q es =
-  let (rws, cs', dynQ) = runQuery' q (components es)
-   in do
-        res <- DQ.readQuerySingleDyn (reads rws <> writes rws) dynQ es
-        return (res, es {components = cs'})
+readQuerySingle ::
+  (HasCallStack, Monad m) =>
+  (forall f. (Applicative f) => Query f m (f a)) ->
+  Entities m ->
+  m a
+readQuerySingle = runner readQuerySingleDyn
 {-# INLINE readQuerySingle #-}
 
 -- | Run a query on all matching entities, potentially modifying them.
-runQuery :: (Monad m) => (forall f. (Applicative f) => Query f m (f a)) -> Entities m -> m ([a], Entities m, Access m ())
-runQuery q es =
-  let (rws, cs', dynQ) = runQuery' q $ components es
-   in DQ.runQueryDyn (reads rws <> writes rws) dynQ es {components = cs'}
+runQuery ::
+  (Monad m) =>
+  (forall f. (Applicative f) => Query f m (f a)) ->
+  Entities m ->
+  m ([a], Entities m, Access m ())
+runQuery = runner runQueryDyn
 {-# INLINE runQuery #-}
 
 -- | Run a query on a single matching entity, potentially modifying it.
-runQuerySingle :: (HasCallStack, Monad m) => (forall f. (Applicative f) => Query f m (f a)) -> Entities m -> m (a, Entities m, Access m ())
-runQuerySingle q es =
-  let (rws, cs', dynQ) = runQuery' q $ components es
-   in DQ.runQuerySingleDyn (reads rws <> writes rws) dynQ es {components = cs'}
+runQuerySingle ::
+  (HasCallStack, Monad m) =>
+  (forall f. (Applicative f) => Query f m (f a)) ->
+  Entities m ->
+  m (a, Entities m, Access m ())
+runQuerySingle = runner runQuerySingleDyn
 {-# INLINE runQuerySingle #-}
 
+runner ::
+  (Monad m) =>
+  (Set ComponentID -> DynamicQuery m a -> Entities m -> t) ->
+  (forall f. (Applicative f) => Query f m (f a)) ->
+  Entities m ->
+  t
+runner f q es =
+  let (rws, cs', dynQ) = runQuery' q $ components es
+   in f (reads rws <> writes rws) dynQ es {components = cs'}
+{-# INLINE runner #-}
+
 -- | Reads and writes of a `Query`.
 data ReadsWrites = ReadsWrites
   { -- | Component IDs being read.
diff --git a/test/Main.hs b/test/Main.hs
index fe95ad88..ccd27b1b 100644
--- a/test/Main.hs
+++ b/test/Main.hs
@@ -58,8 +58,7 @@ describe "Aztecs.ECS.Hierarchy.update" $ do
 prop_queryEmpty :: Expectation
 prop_queryEmpty =
   let res =
-        fst
-          . runIdentity
+        runIdentity
           . Q.readQuery (Q.query @_ @_ @X)
           $ W.entities W.empty
    in res `shouldMatchList` []
@@ -97,20 +96,20 @@ prop_queryDyn xs =
          in ((e, cs) : acc, wAcc')
       (es, w) = foldr spawner ([], W.empty) xs
       go (e, cs) = do
-        let (res, _) = runIdentity . Q.readQuery (queryComponentIds @X @Identity $ map snd cs) $ W.entities w
+        let res = runIdentity . Q.readQuery (queryComponentIds @X @Identity $ map snd cs) $ W.entities w
         return $ res `shouldContain` [(e, map fst cs)]
    in mapM_ go es
 
 prop_queryTypedComponent :: [X] -> Expectation
 prop_queryTypedComponent xs = do
   let w = foldr (\x -> (\(_, w', _) -> w') . W.spawn (bundle x)) W.empty xs
-      (res, _) = runIdentity . Q.readQuery (Q.query @_ @_ @X) $ W.entities w
+      res = runIdentity . Q.readQuery (Q.query @_ @_ @X) $ W.entities w
   res `shouldMatchList` xs
 
 prop_queryTwoTypedComponents :: [(X, Y)] -> Expectation
 prop_queryTwoTypedComponents xys = do
   let w = foldr (\(x, y) -> (\(_, w', _) -> w') . W.spawn (bundle x <> bundle y)) W.empty xys
-      (res, _) =
+      res =
         runIdentity
           $ Q.readQuery
             ( do
@@ -124,7 +123,7 @@ prop_queryTwoTypedComponents xys = do
 prop_queryThreeTypedComponents :: [(X, Y, Z)] -> Expectation
 prop_queryThreeTypedComponents xyzs = do
   let w = foldr (\(x, y, z) -> (\(_, w', _) -> w') . W.spawn (bundle x <> bundle y <> bundle z)) W.empty xyzs
-      (res, _) =
+      res =
         runIdentity
           $ Q.readQuery
             ( do
@@ -139,14 +138,14 @@ prop_queryThreeTypedComponents xyzs = do
 prop_querySingle :: Expectation
 prop_querySingle =
   let (_, w, _) = W.spawn (bundle $ X 1) W.empty
-      (res, _) = runIdentity $ Q.readQuerySingle (Q.query @_ @_ @X) $ W.entities w
+      res = runIdentity $ Q.readQuerySingle (Q.query @_ @_ @X) $ W.entities w
    in res `shouldBe` X 1
 
 prop_queryMapSingle :: Word8 -> Expectation
 prop_queryMapSingle n =
   let (_, w, _) = W.spawn (bundle $ X 0) W.empty
       w' = foldr (\_ es -> (\(_, es', _) -> es') . runIdentity $ Q.runQuerySingle (Q.queryMap @_ @_ @X $ fmap (\(X x) -> X $ x + 1)) es) (W.entities w) [1 .. n]
-      (res, _) = runIdentity $ Q.readQuerySingle (Q.query @_ @_ @X) w'
+      res = runIdentity $ Q.readQuerySingle (Q.query @_ @_ @X) w'
    in res `shouldBe` X (fromIntegral n)
 
 {-TODO

From 47d31a5156b8aab951b010a6a50ba0c8fc1ed47b Mon Sep 17 00:00:00 2001
From: Matt Hunzinger <matt@hunzinger.me>
Date: Fri, 30 Jan 2026 12:02:49 -0500
Subject: [PATCH 5/6] feat: MonadFix

---
 bench/Bench.hs          | 20 +++++++++++++++-----
 src/Aztecs/ECS/Query.hs |  9 ++++++++-
 src/Aztecs/Hierarchy.hs |  2 +-
 3 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/bench/Bench.hs b/bench/Bench.hs
index bd6da069..1d7635bd 100644
--- a/bench/Bench.hs
+++ b/bench/Bench.hs
@@ -4,12 +4,14 @@
 {-# LANGUAGE GeneralizedNewtypeDeriving #-}
 {-# LANGUAGE MultiParamTypeClasses #-}
 {-# LANGUAGE RankNTypes #-}
+{-# LANGUAGE RecursiveDo #-}
 
 import Aztecs.ECS
 import qualified Aztecs.ECS.Query as Q
 import Aztecs.ECS.World
 import qualified Aztecs.ECS.World as W
 import Control.DeepSeq
+import Control.Monad.Fix
 import Criterion.Main
 import Data.Functor.Identity
 import GHC.Generics
@@ -22,15 +24,21 @@ newtype Velocity = Velocity Int deriving (Show, Generic, NFData)
 
 instance (Monad m) => Component m Velocity
 
-move :: (Applicative f, Monad m) => Q.Query f m (f Position)
+move :: (Applicative f, Monad m) => Query f m (f Position)
 move = do
   vs <- Q.query
-  Q.queryMap $ \ps -> (\(Velocity v) (Position p) -> Position $ p + v) <$> vs <*> ps
+  queryMap $ \ps -> (\(Velocity v) (Position p) -> Position $ p + v) <$> vs <*> ps
 
-run :: (forall f. (Applicative f) => Q.Query f Identity (f Position)) -> World Identity -> [Position]
+moveRec :: (Applicative f, MonadFix m) => Query f m (f Position)
+moveRec = mdo
+  vs <- queryMap $ \vs' -> (\(Position p) (Velocity v) -> Velocity $ p + v) <$> ps <*> vs'
+  ps <- queryMap $ \ps' -> (\(Velocity v) (Position p) -> Position $ p + v) <$> vs <*> ps'
+  return ps
+
+run :: (forall f. (Applicative f) => Query f Identity (f Position)) -> World Identity -> [Position]
 run q = (\(a, _, _) -> a) . runIdentity . Q.runQuery q . entities
 
-runSys :: (forall f. (Applicative f) => Q.Query f Identity (f Position)) -> World Identity -> [Position]
+runSys :: (forall f. (Applicative f) => Query f Identity (f Position)) -> World Identity -> [Position]
 runSys q = fst . runIdentity . runAccess (system $ runQuery q)
 
 main :: IO ()
@@ -39,5 +47,7 @@ main = do
       !w = foldr (const go) W.empty [0 :: Int .. 10000]
   defaultMain
     [ bench "iter" $ nf (run move) w,
-      bench "iterSystem" $ nf (runSys move) w
+      bench "iterSystem" $ nf (runSys move) w,
+      bench "iterRec" $ nf (run moveRec) w,
+      bench "iterRecSystem" $ nf (runSys moveRec) w
     ]
diff --git a/src/Aztecs/ECS/Query.hs b/src/Aztecs/ECS/Query.hs
index ad1934d4..bcb87c00 100644
--- a/src/Aztecs/ECS/Query.hs
+++ b/src/Aztecs/ECS/Query.hs
@@ -70,6 +70,7 @@ import qualified Aztecs.ECS.World.Components as CS
 import Aztecs.ECS.World.Entities (Entities (..))
 import Control.Applicative
 import Control.Applicative.Free
+import Control.Monad.Fix
 import Control.Monad.Free
 import Control.Monad.Reader
 import Control.Monad.State
@@ -93,13 +94,17 @@ data Op f m a where
   QueryOp :: (Component m a) => ComponentID -> Op f m (f a)
   QueryMapOp :: (Component m a) => ComponentID -> (f a -> f a) -> Op f m (f a)
   QueryMapAccumOp :: (Component m b) => ComponentID -> (f b -> f (a, b)) -> Op f m (f (a, b))
+  QueryFix :: (MonadFix m) => (a -> QueryPlan f m a) -> Op f m a
 
 newtype QueryPlan f m a = QueryPlan {unQueryPlan :: Free (Ap (Op f m)) a}
   deriving (Functor, Applicative, Monad)
 
+instance (MonadFix m) => MonadFix (QueryPlan f m) where
+  mfix f = QueryPlan $ liftF $ liftAp $ QueryFix f
+
 -- | Query for matching entities.
 newtype Query f m a = Query {unQuery :: ReaderT Components (QueryPlan f m) a}
-  deriving (Functor, Applicative, Monad)
+  deriving (Functor, Applicative, Monad, MonadFix)
 
 -- | Query the entity ID.
 entity :: forall f m. (Applicative f) => Query f m (f EntityID)
@@ -159,6 +164,7 @@ buildQueryPlan a = DynamicQuery $ \arch -> do
             (arch', xs) = A.zipAlterComponentsAsc f' cId arch
         put (arch', hooks)
         return (QueryStream xs)
+      QueryFix f -> mfix $ \x -> foldFree (runAp go) $ unQueryPlan (f x)
 
 runQuery' :: (Monad m) => (forall f. (Applicative f) => Query f m (f a)) -> Components -> (ReadsWrites, Components, DynamicQuery m a)
 runQuery' q cs =
@@ -178,6 +184,7 @@ runQuery' q cs =
       (QueryMapAccumOp cId _) -> do
         modify (\rws -> rws {writes = Set.insert cId (writes rws)})
         return (Fetch (Const ()))
+      (QueryFix f) -> mfix $ \x -> foldFree (runAp go) $ unQueryPlan (f x)
 
 -- | Query a component dynamically by 'ComponentID'.
 queryDyn :: forall f m a. (Applicative f, Component m a, Monad m) => ComponentID -> Query f m (f a)
diff --git a/src/Aztecs/Hierarchy.hs b/src/Aztecs/Hierarchy.hs
index 8190207c..61a83349 100644
--- a/src/Aztecs/Hierarchy.hs
+++ b/src/Aztecs/Hierarchy.hs
@@ -38,7 +38,7 @@ import Aztecs.ECS
 import qualified Aztecs.ECS.Access as A
 import qualified Aztecs.ECS.Query as Q
 import qualified Aztecs.ECS.System as S
-import Control.Applicative (liftA3)
+import Control.Applicative
 import Data.Map (Map)
 import qualified Data.Map as Map
 import Data.Maybe

From e943abc99976d81006fd5d2649d84b8868e022e4 Mon Sep 17 00:00:00 2001
From: Matt Hunzinger <matt@hunzinger.me>
Date: Fri, 30 Jan 2026 12:09:53 -0500
Subject: [PATCH 6/6] refactor: replace QueryStream with ZipList

---
 src/Aztecs/ECS.hs       |  2 --
 src/Aztecs/ECS/Query.hs | 34 +++++++++++-----------------------
 2 files changed, 11 insertions(+), 25 deletions(-)

diff --git a/src/Aztecs/ECS.hs b/src/Aztecs/ECS.hs
index 8524d3fe..08cd3cb3 100644
--- a/src/Aztecs/ECS.hs
+++ b/src/Aztecs/ECS.hs
@@ -60,7 +60,6 @@ module Aztecs.ECS
     Component (..),
     EntityID,
     Query (..),
-    QueryStream (..),
     entity,
     query,
     queryMap,
@@ -97,7 +96,6 @@ import Aztecs.ECS.Observer
 import Aztecs.ECS.Query
   ( Query (..),
     QueryFilter,
-    QueryStream (..),
     entity,
     query,
     queryMap,
diff --git a/src/Aztecs/ECS/Query.hs b/src/Aztecs/ECS/Query.hs
index bcb87c00..1f18143e 100644
--- a/src/Aztecs/ECS/Query.hs
+++ b/src/Aztecs/ECS/Query.hs
@@ -50,9 +50,6 @@ module Aztecs.ECS.Query
     ReadsWrites (..),
     disjoint,
 
-    -- * QueryStream
-    QueryStream (..),
-
     -- * Re-exports
     DynamicQueryF,
   )
@@ -79,16 +76,6 @@ import qualified Data.Set as Set
 import GHC.Stack
 import Prelude hiding (reads)
 
--- | A list with zip semantics for @Applicative@.
-newtype QueryStream a = QueryStream {unQueryStream :: [a]}
-  deriving (Functor, Show)
-
-instance Applicative QueryStream where
-  pure a = QueryStream [a]
-  {-# INLINE pure #-}
-  QueryStream fs <*> QueryStream xs = QueryStream (zipWith ($) fs xs)
-  {-# INLINE (<*>) #-}
-
 data Op f m a where
   EntityOp :: Op f m (f EntityID)
   QueryOp :: (Component m a) => ComponentID -> Op f m (f a)
@@ -100,7 +87,8 @@ newtype QueryPlan f m a = QueryPlan {unQueryPlan :: Free (Ap (Op f m)) a}
   deriving (Functor, Applicative, Monad)
 
 instance (MonadFix m) => MonadFix (QueryPlan f m) where
-  mfix f = QueryPlan $ liftF $ liftAp $ QueryFix f
+  mfix = QueryPlan . liftF . liftAp . QueryFix
+  {-# INLINE mfix #-}
 
 -- | Query for matching entities.
 newtype Query f m a = Query {unQuery :: ReaderT Components (QueryPlan f m) a}
@@ -138,32 +126,32 @@ queryMapAccum f = Query $ do
 newtype Fetch a = Fetch (Const () a)
   deriving (Functor, Applicative)
 
-buildQueryPlan :: (Monad m) => QueryPlan QueryStream m (QueryStream a) -> DynamicQuery m a
+buildQueryPlan :: (Monad m) => QueryPlan ZipList m (ZipList a) -> DynamicQuery m a
 buildQueryPlan a = DynamicQuery $ \arch -> do
   (as, (arch', hooks)) <- runStateT (foldFree (runAp go) $ unQueryPlan a) (arch, pure ())
-  return (unQueryStream as, arch', hooks)
+  return (getZipList as, arch', hooks)
   where
-    go :: (Monad m) => Op QueryStream m x -> StateT (Archetype m, Access m ()) m x
+    go :: (Monad m) => Op ZipList m x -> StateT (Archetype m, Access m ()) m x
     go = \case
       EntityOp -> do
         (arch, _) <- get
-        return $ QueryStream $ Set.toList $ A.entities arch
+        return $ ZipList $ Set.toList $ A.entities arch
       QueryOp cId -> do
         (arch, hooks) <- get
         (as, arch', hooks') <- lift $ runDynQuery (DQ.queryDyn cId) arch
         put (arch', hooks >> hooks')
-        return (QueryStream as)
+        return (ZipList as)
       QueryMapOp cId f -> do
         (arch, hooks) <- get
-        let (arch', as') = A.alterComponentsAsc (unQueryStream . f . QueryStream) cId arch
+        let (arch', as') = A.alterComponentsAsc (getZipList . f . ZipList) cId arch
         put (arch', hooks)
-        return (QueryStream as')
+        return (ZipList as')
       QueryMapAccumOp cId f -> do
         (arch, hooks) <- get
-        let f' = fmap (\(a', b) -> (b, (a', b))) . unQueryStream . f . QueryStream
+        let f' = fmap (\(a', b) -> (b, (a', b))) . getZipList . f . ZipList
             (arch', xs) = A.zipAlterComponentsAsc f' cId arch
         put (arch', hooks)
-        return (QueryStream xs)
+        return (ZipList xs)
       QueryFix f -> mfix $ \x -> foldFree (runAp go) $ unQueryPlan (f x)
 
 runQuery' :: (Monad m) => (forall f. (Applicative f) => Query f m (f a)) -> Components -> (ReadsWrites, Components, DynamicQuery m a)