UniqueLogic.ST.System.Label

Preparation

type Variable w = Variable (WriterT w)

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

Posing statements

type T w = T (WriterT w)

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

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

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

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

data Apply w s a

Instances

Applicative (Apply w s)

Defined in UniqueLogic.ST.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

Functor (Apply w s)

Defined in UniqueLogic.ST.System

Methods

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

(<$) :: 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 => Apply w s a -> Variable w s a -> T w s ()

Solution

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

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

queryForbid :: Variable w s (Forbid a) -> ST s (Maybe a)

queryIgnore :: Variable w s (Ignore a) -> ST s (Maybe a)

queryVerify :: Variable w s (Verify a) -> ST s (Maybe a)