Safe Haskell	Safe-Inferred
Language	Haskell2010

Aztecs.ECS

Description

Aztecs is a type-safe and friendly ECS for games and more.

An ECS is a modern approach to organizing your application state as a database, providing patterns for data-oriented design and parallel processing.

The ECS architecture is composed of three main concepts:

Entities

An entity is an object comprised of zero or more components. In Aztecs, entities are represented by their EntityID, a unique identifier.

Components

A Component holds the data for a particular aspect of an entity. For example, a zombie entity might have a Health and a Transform component.

newtype Position = Position Int deriving (Show)
instance Component Position

newtype Velocity = Velocity Int deriving (Show)
instance Component Velocity

Systems

A System is a pipeline that processes entities and their components. Systems in Aztecs either run in sequence or in parallel automatically based on the components they access.

Systems can access game state in two ways:

Access

An Access can be queued for full access to the World, after a system is complete. Access allows for spawning, inserting, and removing components.

setup :: System  () ()
setup = S.queue . const . A.spawn_ $ bundle (Position 0) <> bundle (Velocity 1)

Queries

A Query can read and write matching components.

move :: System  () ()
move =
 S.map
   ( proc () -> do
       Velocity v <- Q.fetch -< ()
       Position p <- Q.fetch -< ()
       Q.set -< Position $ p + v
   )
   >>> S.run print

Finally, systems can be run on a World to produce a result.

main :: IO ()
main = runSystem_ $ setup >>> S.forever move

Synopsis

type Access = AccessT Identity
runAccessT :: Functor m => AccessT m a -> World -> m (a, World)
data Bundle
class Monoid a => MonoidBundle a where
- bundle :: forall c. Component c => c -> a
data DynamicBundle
class MonoidDynamicBundle a where
- dynBundle :: Component c => ComponentID -> c -> a
class (Typeable a, Storage a (StorageT a)) => Component a where
- type StorageT a :: Type
data EntityID
data Query i o
class Arrow arr => ArrowQueryReader arr
class ArrowQueryReader arr => ArrowQuery arr
class Arrow arr => ArrowDynamicQueryReader arr
class ArrowDynamicQueryReader arr => ArrowDynamicQuery arr
data QueryFilter
with :: forall a. Component a => QueryFilter
without :: forall a. Component a => QueryFilter
type System = SystemT Identity
class Arrow arr => ArrowReaderSystem q arr | arr -> q
class Arrow arr => ArrowSystem q arr | arr -> q
class (MonadAccess b m, Arrow arr) => ArrowQueueSystem b m arr | arr -> m
type Schedule m = ScheduleT (AccessT m)
class Arrow arr => ArrowReaderSchedule s arr | arr -> s
class Arrow arr => ArrowSchedule s arr | arr -> s
class (MonadAccess b m, Arrow arr) => ArrowAccessSchedule b m arr | arr -> m
reader :: ArrowReaderSchedule s arr => s i o -> arr i o
system :: ArrowSchedule s arr => s i o -> arr i o
delay :: Monad m => a -> Schedule m a a
forever :: Schedule IO i o -> (o -> IO ()) -> Schedule IO i ()
forever_ :: Schedule IO i o -> Schedule IO i ()
access :: ArrowAccessSchedule b m arr => (i -> m o) -> arr i o
runSchedule :: Monad m => Schedule m i o -> World -> i -> m (o, DynamicSchedule m i o, World)
runSchedule_ :: Monad m => Schedule m () () -> m ()
data World

Documentation

type Access = AccessT Identity Source #

runAccessT :: Functor m => AccessT m a -> World -> m (a, World) Source #

Run an Access on a World, returning the output and updated World.

data Bundle Source #

Bundle of components.

Instances

Instances details

MonoidBundle Bundle Source #
Instance details Defined in Aztecs.ECS.World.Bundle Methods bundle :: Component c => c -> Bundle Source #
MonoidDynamicBundle Bundle Source #
Instance details Defined in Aztecs.ECS.World.Bundle Methods dynBundle :: Component c => ComponentID -> c -> Bundle Source #
Monoid Bundle Source #
Instance details Defined in Aztecs.ECS.World.Bundle Methods mempty :: Bundle # mappend :: Bundle -> Bundle -> Bundle # mconcat :: [Bundle] -> Bundle #
Semigroup Bundle Source #
Instance details Defined in Aztecs.ECS.World.Bundle Methods (<>) :: Bundle -> Bundle -> Bundle # sconcat :: NonEmpty Bundle -> Bundle # stimes :: Integral b => b -> Bundle -> Bundle #
ArrowQueueSystem Bundle Access QueueSystem Source #
Instance details Defined in Aztecs.ECS.System.Queue Methods queue :: (i -> Access ()) -> QueueSystem i () Source #
Monad m => MonadAccess Bundle (AccessT m) Source #
Instance details Defined in Aztecs.ECS.Access Methods spawn :: Bundle -> AccessT m EntityID Source # spawn_ :: Bundle -> AccessT m () Source # insert :: Component a => EntityID -> a -> AccessT m () Source # lookup :: Component a => EntityID -> AccessT m (Maybe a) Source # remove :: Component a => EntityID -> AccessT m (Maybe a) Source # despawn :: EntityID -> AccessT m () Source #
Monad m => ArrowAccessSchedule Bundle (AccessT m) (Schedule m) Source #
Instance details Defined in Aztecs.ECS.Schedule Methods access :: (i -> AccessT m o) -> Schedule m i o Source #
Monad m => ArrowAccessSchedule Bundle (AccessT m) (AcessSchedule m) Source #
Instance details Defined in Aztecs.ECS.Schedule.Access Methods access :: (i -> AccessT m o) -> AcessSchedule m i o Source #
Monad m => ArrowQueueSystem Bundle (AccessT m) (SystemT m) Source #
Instance details Defined in Aztecs.ECS.System Methods queue :: (i -> AccessT m ()) -> SystemT m i () Source #
Monad m => ArrowQueueSystem Bundle (AccessT m) (DynamicSystemT m) Source #
Instance details Defined in Aztecs.ECS.System.Dynamic Methods queue :: (i -> AccessT m ()) -> DynamicSystemT m i () Source #
Monad m => ArrowQueueSystem Bundle (AccessT m) (DynamicReaderSystemT m) Source #
Instance details Defined in Aztecs.ECS.System.Dynamic.Reader Methods queue :: (i -> AccessT m ()) -> DynamicReaderSystemT m i () Source #
Monad m => ArrowQueueSystem Bundle (AccessT m) (ReaderSystemT m) Source #
Instance details Defined in Aztecs.ECS.System.Reader Methods queue :: (i -> AccessT m ()) -> ReaderSystemT m i () Source #

class Monoid a => MonoidBundle a where Source #

Monoid bundle of components.

Methods

bundle :: forall c. Component c => c -> a Source #

Add a component to the bundle.

Instances

Instances details

MonoidBundle Bundle Source #
Instance details Defined in Aztecs.ECS.World.Bundle Methods bundle :: Component c => c -> Bundle Source #

data DynamicBundle Source #

Dynamic bundle of components.

Instances

Instances details

MonoidDynamicBundle DynamicBundle Source #
Instance details Defined in Aztecs.ECS.World.Bundle.Dynamic Methods dynBundle :: Component c => ComponentID -> c -> DynamicBundle Source #
Monoid DynamicBundle Source #
Instance details Defined in Aztecs.ECS.World.Bundle.Dynamic Methods mempty :: DynamicBundle # mappend :: DynamicBundle -> DynamicBundle -> DynamicBundle # mconcat :: [DynamicBundle] -> DynamicBundle #
Semigroup DynamicBundle Source #
Instance details Defined in Aztecs.ECS.World.Bundle.Dynamic Methods (<>) :: DynamicBundle -> DynamicBundle -> DynamicBundle # sconcat :: NonEmpty DynamicBundle -> DynamicBundle # stimes :: Integral b => b -> DynamicBundle -> DynamicBundle #

class MonoidDynamicBundle a where Source #

Monoid bundle of dynamic components.

Methods

dynBundle :: Component c => ComponentID -> c -> a Source #

Add a component to the bundle by its ComponentID.

Instances

Instances details

MonoidDynamicBundle Bundle Source #
Instance details Defined in Aztecs.ECS.World.Bundle Methods dynBundle :: Component c => ComponentID -> c -> Bundle Source #
MonoidDynamicBundle DynamicBundle Source #
Instance details Defined in Aztecs.ECS.World.Bundle.Dynamic Methods dynBundle :: Component c => ComponentID -> c -> DynamicBundle Source #

class (Typeable a, Storage a (StorageT a)) => Component a Source #

Component that can be stored in the World.

Associated Types

type StorageT a :: Type Source #

Storage of this component.

type StorageT a = [a]

Instances

Instances details

Component Camera Source #
Instance details Defined in Aztecs.Camera Associated Types type StorageT Camera Source #
Component CameraTarget Source #
Instance details Defined in Aztecs.Camera Associated Types type StorageT CameraTarget Source #
Component ChildState Source #
Instance details Defined in Aztecs.Hierarchy Associated Types type StorageT ChildState Source #
Component Children Source #
Instance details Defined in Aztecs.Hierarchy Associated Types type StorageT Children Source #
Component Parent Source #
Instance details Defined in Aztecs.Hierarchy Associated Types type StorageT Parent Source #
Component ParentState Source #
Instance details Defined in Aztecs.Hierarchy Associated Types type StorageT ParentState Source #
Component KeyboardInput Source #
Instance details Defined in Aztecs.Input Associated Types type StorageT KeyboardInput Source #
Component MouseInput Source #
Instance details Defined in Aztecs.Input Associated Types type StorageT MouseInput Source #
Component Time Source #
Instance details Defined in Aztecs.Time Associated Types type StorageT Time Source #
Component Window Source #
Instance details Defined in Aztecs.Window Associated Types type StorageT Window Source #
Typeable a => Component (AssetServer a) Source #
Instance details Defined in Aztecs.Asset.AssetServer Associated Types type StorageT (AssetServer a) Source #
Component (Size (V2 Int)) Source #
Instance details Defined in Aztecs.Transform Associated Types type StorageT (Size (V2 Int)) Source #
Component (Transform (V2 Int) Int) Source #
Instance details Defined in Aztecs.Transform Associated Types type StorageT (Transform (V2 Int) Int) Source #

data EntityID Source #

Entity ID.

Instances

Instances details

Generic EntityID Source #
Instance details Defined in Aztecs.ECS.Entity Associated Types type Rep EntityID :: Type -> Type # Methods from :: EntityID -> Rep EntityID x # to :: Rep EntityID x -> EntityID #
Show EntityID Source #
Instance details Defined in Aztecs.ECS.Entity Methods showsPrec :: Int -> EntityID -> ShowS # show :: EntityID -> String # showList :: [EntityID] -> ShowS #
NFData EntityID Source #
Instance details Defined in Aztecs.ECS.Entity Methods rnf :: EntityID -> () #
Eq EntityID Source #
Instance details Defined in Aztecs.ECS.Entity Methods (==) :: EntityID -> EntityID -> Bool # (/=) :: EntityID -> EntityID -> Bool #
Ord EntityID Source #
Instance details Defined in Aztecs.ECS.Entity Methods compare :: EntityID -> EntityID -> Ordering # (<) :: EntityID -> EntityID -> Bool # (<=) :: EntityID -> EntityID -> Bool # (>) :: EntityID -> EntityID -> Bool # (>=) :: EntityID -> EntityID -> Bool # max :: EntityID -> EntityID -> EntityID # min :: EntityID -> EntityID -> EntityID #
type Rep EntityID Source #
Instance details Defined in Aztecs.ECS.Entity type Rep EntityID = D1 ('MetaData "EntityID" "Aztecs.ECS.Entity" "aztecs-0.8.0-5YWGoxTs0Vw9iciqZAe9GO" 'True) (C1 ('MetaCons "EntityID" 'PrefixI 'True) (S1 ('MetaSel ('Just "unEntityId") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Int)))

data Query i o Source #

Query for matching entities.

Do notation:

move :: (ArrowQuery arr) => arr () Position
move = proc () -> do
  Velocity v <- Q.fetch -< ()
  Position p <- Q.fetch -< ()
  Q.set -< Position $ p + v

Arrow combinators:

move :: (ArrowQuery arr) => arr () Position
move = Q.fetch &&& Q.fetch >>> arr (\(Position p, Velocity v) -> Position $ p + v) >>> Q.set

Applicative combinators:

move :: (ArrowQuery arr) => arr () Position
move = (,) <$> Q.fetch <*> Q.fetch >>> arr (\(Position p, Velocity v) -> Position $ p + v) >>> Q.set

Instances

Instances details

ArrowQuery Query Source #
Instance details Defined in Aztecs.ECS.Query Methods set :: Component a => Query a a Source #
ArrowDynamicQuery Query Source #
Instance details Defined in Aztecs.ECS.Query Methods setDyn :: Component a => ComponentID -> Query a a Source #
ArrowDynamicQueryReader Query Source #
Instance details Defined in Aztecs.ECS.Query Methods entity :: Query () EntityID Source # fetchDyn :: Component a => ComponentID -> Query () a Source # fetchMaybeDyn :: Component a => ComponentID -> Query () (Maybe a) Source #
ArrowQueryReader Query Source #
Instance details Defined in Aztecs.ECS.Query Methods fetch :: Component a => Query () a Source # fetchMaybe :: Component a => Query () (Maybe a) Source #
Arrow Query Source #
Instance details Defined in Aztecs.ECS.Query Methods arr :: (b -> c) -> Query b c # first :: Query b c -> Query (b, d) (c, d) # second :: Query b c -> Query (d, b) (d, c) # (***) :: Query b c -> Query b' c' -> Query (b, b') (c, c') # (&&&) :: Query b c -> Query b c' -> Query b (c, c') #
ArrowChoice Query Source #
Instance details Defined in Aztecs.ECS.Query Methods left :: Query b c -> Query (Either b d) (Either c d) # right :: Query b c -> Query (Either d b) (Either d c) # (+++) :: Query b c -> Query b' c' -> Query (Either b b') (Either c c') # (\|\|\|) :: Query b d -> Query c d -> Query (Either b c) d #
Category Query Source #
Instance details Defined in Aztecs.ECS.Query Methods id :: forall (a :: k). Query a a # (.) :: forall (b :: k) (c :: k) (a :: k). Query b c -> Query a b -> Query a c #
Monad m => ArrowSystem Query (SystemT m) Source #
Instance details Defined in Aztecs.ECS.System Methods map :: Query i a -> SystemT m i [a] Source # map_ :: Query i o -> SystemT m i () Source # filterMap :: Query i a -> QueryFilter -> SystemT m i [a] Source # mapSingle :: Query i a -> SystemT m i a Source # mapSingleMaybe :: Query i a -> SystemT m i (Maybe a) Source #
Applicative (Query i) Source #
Instance details Defined in Aztecs.ECS.Query Methods pure :: a -> Query i a # (<>) :: Query i (a -> b) -> Query i a -> Query i b # liftA2 :: (a -> b -> c) -> Query i a -> Query i b -> Query i c # (>) :: Query i a -> Query i b -> Query i b # (<*) :: Query i a -> Query i b -> Query i a #
Functor (Query i) Source #
Instance details Defined in Aztecs.ECS.Query Methods fmap :: (a -> b) -> Query i a -> Query i b # (<$) :: a -> Query i b -> Query i a #

class Arrow arr => ArrowQueryReader arr Source #

Arrow for queries that can read from entities.

Minimal complete definition

fetch

Instances

Instances details

ArrowQueryReader Query Source #
Instance details Defined in Aztecs.ECS.Query Methods fetch :: Component a => Query () a Source # fetchMaybe :: Component a => Query () (Maybe a) Source #
ArrowQueryReader QueryReader Source #
Instance details Defined in Aztecs.ECS.Query.Reader Methods fetch :: Component a => QueryReader () a Source # fetchMaybe :: Component a => QueryReader () (Maybe a) Source #

class ArrowQueryReader arr => ArrowQuery arr Source #

Arrow for queries that can update entities.

Minimal complete definition

set

Instances

Instances details

ArrowQuery Query Source #
Instance details Defined in Aztecs.ECS.Query Methods set :: Component a => Query a a Source #

class Arrow arr => ArrowDynamicQueryReader arr Source #

Minimal complete definition

entity, fetchDyn

Instances

Instances details

ArrowDynamicQueryReader Query Source #
Instance details Defined in Aztecs.ECS.Query Methods entity :: Query () EntityID Source # fetchDyn :: Component a => ComponentID -> Query () a Source # fetchMaybeDyn :: Component a => ComponentID -> Query () (Maybe a) Source #
ArrowDynamicQueryReader DynamicQuery Source #
Instance details Defined in Aztecs.ECS.Query.Dynamic Methods entity :: DynamicQuery () EntityID Source # fetchDyn :: Component a => ComponentID -> DynamicQuery () a Source # fetchMaybeDyn :: Component a => ComponentID -> DynamicQuery () (Maybe a) Source #
ArrowDynamicQueryReader DynamicQueryReader Source #
Instance details Defined in Aztecs.ECS.Query.Dynamic.Reader Methods entity :: DynamicQueryReader () EntityID Source # fetchDyn :: Component a => ComponentID -> DynamicQueryReader () a Source # fetchMaybeDyn :: Component a => ComponentID -> DynamicQueryReader () (Maybe a) Source #
ArrowDynamicQueryReader QueryReader Source #
Instance details Defined in Aztecs.ECS.Query.Reader Methods entity :: QueryReader () EntityID Source # fetchDyn :: Component a => ComponentID -> QueryReader () a Source # fetchMaybeDyn :: Component a => ComponentID -> QueryReader () (Maybe a) Source #

class ArrowDynamicQueryReader arr => ArrowDynamicQuery arr Source #

Minimal complete definition

setDyn

Instances

Instances details

ArrowDynamicQuery Query Source #
Instance details Defined in Aztecs.ECS.Query Methods setDyn :: Component a => ComponentID -> Query a a Source #
ArrowDynamicQuery DynamicQuery Source #
Instance details Defined in Aztecs.ECS.Query.Dynamic Methods setDyn :: Component a => ComponentID -> DynamicQuery a a Source #

data QueryFilter Source #

Filter for a Query.

Instances

Instances details

Monoid QueryFilter Source #
Instance details Defined in Aztecs.ECS.Query.Reader Methods mempty :: QueryFilter # mappend :: QueryFilter -> QueryFilter -> QueryFilter # mconcat :: [QueryFilter] -> QueryFilter #
Semigroup QueryFilter Source #
Instance details Defined in Aztecs.ECS.Query.Reader Methods (<>) :: QueryFilter -> QueryFilter -> QueryFilter # sconcat :: NonEmpty QueryFilter -> QueryFilter # stimes :: Integral b => b -> QueryFilter -> QueryFilter #

with :: forall a. Component a => QueryFilter Source #

Filter for entities containing this component.

without :: forall a. Component a => QueryFilter Source #

Filter out entities containing this component.

type System = SystemT Identity Source #

class Arrow arr => ArrowReaderSystem q arr | arr -> q Source #

Minimal complete definition

all, filter

Instances

Instances details

Monad m => ArrowReaderSystem QueryReader (SystemT m) Source #
Instance details Defined in Aztecs.ECS.System Methods all :: QueryReader i a -> SystemT m i [a] Source # filter :: QueryReader () a -> QueryFilter -> SystemT m () [a] Source # single :: QueryReader i a -> SystemT m i a Source #
Monad m => ArrowReaderSystem QueryReader (ReaderSystemT m) Source #
Instance details Defined in Aztecs.ECS.System.Reader Methods all :: QueryReader i a -> ReaderSystemT m i [a] Source # filter :: QueryReader () a -> QueryFilter -> ReaderSystemT m () [a] Source # single :: QueryReader i a -> ReaderSystemT m i a Source #

class Arrow arr => ArrowSystem q arr | arr -> q Source #

Minimal complete definition

map, filterMap, mapSingle, mapSingleMaybe

Instances

Instances details

Monad m => ArrowSystem Query (SystemT m) Source #
Instance details Defined in Aztecs.ECS.System Methods map :: Query i a -> SystemT m i [a] Source # map_ :: Query i o -> SystemT m i () Source # filterMap :: Query i a -> QueryFilter -> SystemT m i [a] Source # mapSingle :: Query i a -> SystemT m i a Source # mapSingleMaybe :: Query i a -> SystemT m i (Maybe a) Source #

class (MonadAccess b m, Arrow arr) => ArrowQueueSystem b m arr | arr -> m Source #

Minimal complete definition

queue

Instances

Instances details

ArrowQueueSystem Bundle Access QueueSystem Source #
Instance details Defined in Aztecs.ECS.System.Queue Methods queue :: (i -> Access ()) -> QueueSystem i () Source #
Monad m => ArrowQueueSystem Bundle (AccessT m) (SystemT m) Source #
Instance details Defined in Aztecs.ECS.System Methods queue :: (i -> AccessT m ()) -> SystemT m i () Source #
Monad m => ArrowQueueSystem Bundle (AccessT m) (DynamicSystemT m) Source #
Instance details Defined in Aztecs.ECS.System.Dynamic Methods queue :: (i -> AccessT m ()) -> DynamicSystemT m i () Source #
Monad m => ArrowQueueSystem Bundle (AccessT m) (DynamicReaderSystemT m) Source #
Instance details Defined in Aztecs.ECS.System.Dynamic.Reader Methods queue :: (i -> AccessT m ()) -> DynamicReaderSystemT m i () Source #
Monad m => ArrowQueueSystem Bundle (AccessT m) (ReaderSystemT m) Source #
Instance details Defined in Aztecs.ECS.System.Reader Methods queue :: (i -> AccessT m ()) -> ReaderSystemT m i () Source #

type Schedule m = ScheduleT (AccessT m) Source #

class Arrow arr => ArrowReaderSchedule s arr | arr -> s Source #

Schedule arrow that runs read-only systems.

Minimal complete definition

reader

Instances

Instances details

Monad m => ArrowReaderSchedule (ReaderSystemT m) (Schedule m) Source #
Instance details Defined in Aztecs.ECS.Schedule Methods reader :: ReaderSystemT m i o -> Schedule m i o Source #

class Arrow arr => ArrowSchedule s arr | arr -> s Source #

Schedule arrow that runs systems.

Minimal complete definition

system

Instances

Instances details

Monad m => ArrowSchedule (SystemT m) (Schedule m) Source #
Instance details Defined in Aztecs.ECS.Schedule Methods system :: SystemT m i o -> Schedule m i o Source #

class (MonadAccess b m, Arrow arr) => ArrowAccessSchedule b m arr | arr -> m Source #

Schedule arrow that provides access to a World.

Minimal complete definition

access

Instances

Instances details

Monad m => ArrowAccessSchedule Bundle (AccessT m) (Schedule m) Source #
Instance details Defined in Aztecs.ECS.Schedule Methods access :: (i -> AccessT m o) -> Schedule m i o Source #
Monad m => ArrowAccessSchedule Bundle (AccessT m) (AcessSchedule m) Source #
Instance details Defined in Aztecs.ECS.Schedule.Access Methods access :: (i -> AccessT m o) -> AcessSchedule m i o Source #

reader :: ArrowReaderSchedule s arr => s i o -> arr i o Source #

Schedule a reader system.

system :: ArrowSchedule s arr => s i o -> arr i o Source #

Schedule a system.

delay :: Monad m => a -> Schedule m a a Source #

forever :: Schedule IO i o -> (o -> IO ()) -> Schedule IO i () Source #

forever_ :: Schedule IO i o -> Schedule IO i () Source #

access :: ArrowAccessSchedule b m arr => (i -> m o) -> arr i o Source #

Access the World.

runSchedule :: Monad m => Schedule m i o -> World -> i -> m (o, DynamicSchedule m i o, World) Source #

runSchedule_ :: Monad m => Schedule m () () -> m () Source #

data World Source #

World of entities and their components.

Instances

Instances details

Generic World Source #
Instance details Defined in Aztecs.ECS.World Associated Types type Rep World :: Type -> Type # Methods from :: World -> Rep World x # to :: Rep World x -> World #
Show World Source #
Instance details Defined in Aztecs.ECS.World Methods showsPrec :: Int -> World -> ShowS # show :: World -> String # showList :: [World] -> ShowS #
NFData World Source #
Instance details Defined in Aztecs.ECS.World Methods rnf :: World -> () #
type Rep World Source #
Instance details Defined in Aztecs.ECS.World type Rep World = D1 ('MetaData "World" "Aztecs.ECS.World" "aztecs-0.8.0-5YWGoxTs0Vw9iciqZAe9GO" 'False) (C1 ('MetaCons "World" 'PrefixI 'True) (S1 ('MetaSel ('Just "entities") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Entities) :*: S1 ('MetaSel ('Just "nextEntityId") 'NoSourceUnpackedness 'SourceStrict 'DecidedStrict) (Rec0 EntityID)))