UniqueLogic.ST.TF.System.Label

Preparation

type Variable w = Variable (WriterT w)

globalVariable :: (Monoid w, C s) => (a -> Writer w a) -> s (Variable w s a)

Posing statements

type T w = T (WriterT w)

localVariable :: (C w, Value w a, C s) => T w s (Variable w s a)

constant :: (C w, Value w a, C s) => a -> T w s (Variable w s a)

assignment2 :: (C w, C s) => (a -> b) -> Variable w s a -> Variable w s b -> T w s ()

assignment2 f a b = runApply (f <$> arg a) b

assignment3 :: (C w, C s) => (a -> b -> c) -> Variable w s a -> Variable w s b -> Variable w s c -> T w s ()

assignment3 f a b c = runApply (liftA2 f (arg a) (arg b)) c

data Apply w s a

Instances

C s => Functor (Apply w s)

Defined in UniqueLogic.ST.TF.System

Methods

fmap :: (a -> b) -> Apply w s a -> Apply w s b

(<$) :: a -> Apply w s b -> Apply w s a

C s => Applicative (Apply w s)

Defined in UniqueLogic.ST.TF.System

Methods

pure :: a -> Apply w s a

(<*>) :: Apply w s (a -> b) -> Apply w s a -> Apply w s b

liftA2 :: (a -> b -> c) -> Apply w s a -> Apply w s b -> Apply w s c

(*>) :: Apply w s a -> Apply w s b -> Apply w s b

(<*) :: Apply w s a -> Apply w s b -> Apply w s a

arg :: Variable w s a -> Apply w s a

This function allows to generalize assignment2 and assignment3 to more arguments. You could achieve the same with nested applications of assignment3 (,).

runApply :: (C w, C s) => Apply w s a -> Variable w s a -> T w s ()

Solution

solve :: (C w, C s) => T w s a -> w s a

query :: Variable w s a -> s (Maybe a)