category-extras-0.52.3: Various modules and constructs inspired by category theory

Portabilitynon-portable (rank-2 polymorphism)
MaintainerEdward Kmett <>



Ghani and Johann's Interp/InterpT types from ''Initial Algebra Semantics is Enough!'' and its dual.


type Interpreter y g h = y :~> Ran g hSource

type InterpreterT f g h = forall y. Functor y => Interpreter y g h -> Interpreter (f y) g hSource

type Cointerpreter y g h = Lan g h :~> ySource

type CointerpreterT f g h = forall y. Functor y => Cointerpreter y g h -> Cointerpreter (f y) g hSource