Data.Recursive.Propagator.Naive

A very naive propagator library.

This propagator implementation keeps updating the values accoring to their definitions as other values change, until a fixed-point is reached.

It is a naive implementation and not very clever. Much more efficient propagator implementations are possible, and may be used by this library in the future.

Documentation

data Prop a

A cell in a propagator network

Instances

Bottom x => Propagator (Prop x) x

Defined in Data.Recursive.Propagator.Class

Methods

newProp :: IO (Prop x)

newConstProp :: x -> IO (Prop x)

readProp :: Prop x -> IO x

newProp :: a -> IO (Prop a)

Creates a cell, given an initial value

readProp :: Prop a -> IO a

Reads the current value of the cell

watchProp :: Prop a -> IO () -> IO ()

Watch a cell: If the value changes, the given action is executed

setProp :: Eq a => Prop a -> IO a -> IO ()

Sets a new value calculated from the given action. The action is executed atomically.

If the value has changed, all watchers are notified afterwards (not atomically).

lift1 :: Eq b => (a -> b) -> Prop a -> Prop b -> IO ()

Whenever the first cell changes, update the second, using the given function

lift2 :: Eq c => (a -> b -> c) -> Prop a -> Prop b -> Prop c -> IO ()

Whenever any of the first two cells change, update the third, using the given function

liftList :: Eq b => ([a] -> b) -> [Prop a] -> Prop b -> IO ()

Whenever any of the cells in the list change, update the other, using the given function