adam@15: (* Reactive sources that accept change listeners *)
kkallio@14: 
adam@15: con t :: Type -> Type
kkallio@14: 
adam@15: val create : a ::: Type -> a -> transaction (t a)
kkallio@14: 
adam@15: val onChange : a ::: Type -> t a -> (a -> transaction {}) -> transaction {}
kkallio@14: 
adam@15: val set : a ::: Type -> t a -> a -> transaction {}
adam@15: val get : a ::: Type -> t a -> transaction a
adam@15: val value : a ::: Type -> t a -> signal a