ECS

data ComponentR a = ComponentR
  { entity :: EntityId
  , info   :: InfoR a
  }

data InfoR a = InfoR
  { get :: a
  }

data World = World
  { configuration              :: WConfig
  , componentsOfSingleType     :: ??? -> ???
  , componentOfSingleTypeForId :: EntityId -> ??? -> ???
  }

data WConfig = WConfig
  { components :: [ComponentR]
  , systems    :: [[ComponentR] -> ComponentR] -- Parameter is an heterogeneous list 
  , -- other stuff
  }
  
-- Client code

newtype HealthR =
  HealthR Int

newtype StaminaR =
  StaminaR Int

healths =
  [ ComponentR {entity = 1, info = InfoR {get = HealthR 1}}
  , ComponentR {entity = 2, info = InfoR {get = HealthR 1}}
  ]

staminas = [ComponentR {entity = 1, info = InfoR {get = StaminaR 1}}]

myConfig = WConfig {components = healths ++ staminas} -- Error, obvious type mismatch

myWorld =
  World
  { configuration = myConfig
  , componentsOfSingleType = ???
  , componentOfSingleTypeForId = ???
  }