Portability | non-portable (GHC extensions) |
---|---|

Stability | provisional |

Maintainer | nilsson@cs.yale.edu |

New version using GADTs.

ToDo:

- Specialize def. of repeatedly. Could have an impact on invaders.
- New defs for accs using SFAcc
- Make sure opt worked: e.g.

repeatedly >>> count >>> arr (fmap sqr)

- Introduce SFAccHld.
- See if possible to unify AccHld wity Acc??? They are so close.
- Introduce SScan. BUT KEEP IN MIND: Most if not all opts would have been possible without GADTs???
- Look into pairs. At least pairing of SScan ought to be interesting.
- Would be nice if we could get rid of first & second with impunity thanks to Id optimizations. That's a clear win, with or without an explicit pair combinator.
- delayEventCat is a bit complicated ...

Random ideas:

- What if one used rules to optimize - (arr :: SF a ()) to (constant ()) - (arr :: SF a a) to identity But inspection of invader source code seem to indicate that these are not very common cases at all.
- It would be nice if it was possible to come up with opt. rules that are invariant of how signal function expressions are parenthesized. Right now, we have e.g. arr f >>> (constant c >>> sf) being optimized to cpAuxA1 f (cpAuxC1 c sf) whereas it clearly should be possible to optimize to just cpAuxC1 c sf What if we didn't use SF' but SFComp :: tfun -> SF' a b -> SF' b c -> SF' a c ???
- The transition function would still be optimized in (pretty much) the current way, but it would still be possible to look inside composed signal functions for lost optimization opts. Seems to me this could be done without too much extra effort/no dupl. work. E.g. new cpAux, the general case:

cpAux sf1 sf2 = SFComp tf sf1 sf2 where tf dt a = (cpAux sf1' sf2', c) where (sf1', b) = (sfTF' sf1) dt a (sf2', c) = (sfTF' sf2) dt b

- The ONLY change was changing the constructor from SF' to SFComp and adding sf1 and sf2 to the constructor app.!
- An optimized case: cpAuxC1 b sf1 sf2 = SFComp tf sf1 sf2 So cpAuxC1 gets an extra arg, and we change the constructor. But how to exploit without writing 1000s of rules??? Maybe define predicates on SFComp to see if the first or second sf are interesting, and if so, make reassociate and make a recursive call? E.g. we're in the arr case, and the first sf is another arr, so we'd like to combine the two.
- It would also be intersting, then, to know when to STOP playing this game, due to the overhead involved.
- Why don't we have a SWITCH constructor that indicates that the structure will change, and thus that it is worthwile to keep looking for opt. opportunities, whereas a plain SF' would indicate that things NEVER are going to change, and thus we can just as well give up?

- module Control.Arrow
- module FRP.Yampa.VectorSpace
- class RandomGen g where
- class Random a where
- (#) :: (a -> b) -> (b -> c) -> a -> c
- dup :: a -> (a, a)
- swap :: (a, b) -> (b, a)
- type Time = Double
- data SF a b
- data Event a
- arrPrim :: (a -> b) -> SF a b
- arrEPrim :: (Event a -> b) -> SF (Event a) b
- identity :: SF a a
- constant :: b -> SF a b
- localTime :: SF a Time
- time :: SF a Time
- (-->) :: b -> SF a b -> SF a b
- (>--) :: a -> SF a b -> SF a b
- (-=>) :: (b -> b) -> SF a b -> SF a b
- (>=-) :: (a -> a) -> SF a b -> SF a b
- initially :: a -> SF a a
- sscan :: (b -> a -> b) -> b -> SF a b
- sscanPrim :: (c -> a -> Maybe (c, b)) -> c -> b -> SF a b
- never :: SF a (Event b)
- now :: b -> SF a (Event b)
- after :: Time -> b -> SF a (Event b)
- repeatedly :: Time -> b -> SF a (Event b)
- afterEach :: [(Time, b)] -> SF a (Event b)
- afterEachCat :: [(Time, b)] -> SF a (Event [b])
- delayEvent :: Time -> SF (Event a) (Event a)
- delayEventCat :: Time -> SF (Event a) (Event [a])
- edge :: SF Bool (Event ())
- iEdge :: Bool -> SF Bool (Event ())
- edgeTag :: a -> SF Bool (Event a)
- edgeJust :: SF (Maybe a) (Event a)
- edgeBy :: (a -> a -> Maybe b) -> a -> SF a (Event b)
- notYet :: SF (Event a) (Event a)
- once :: SF (Event a) (Event a)
- takeEvents :: Int -> SF (Event a) (Event a)
- dropEvents :: Int -> SF (Event a) (Event a)
- switch :: SF a (b, Event c) -> (c -> SF a b) -> SF a b
- dSwitch :: SF a (b, Event c) -> (c -> SF a b) -> SF a b
- rSwitch :: SF a b -> SF (a, Event (SF a b)) b
- drSwitch :: SF a b -> SF (a, Event (SF a b)) b
- kSwitch :: SF a b -> SF (a, b) (Event c) -> (SF a b -> c -> SF a b) -> SF a b
- dkSwitch :: SF a b -> SF (a, b) (Event c) -> (SF a b -> c -> SF a b) -> SF a b
- parB :: Functor col => col (SF a b) -> SF a (col b)
- pSwitchB :: Functor col => col (SF a b) -> SF (a, col b) (Event c) -> (col (SF a b) -> c -> SF a (col b)) -> SF a (col b)
- dpSwitchB :: Functor col => col (SF a b) -> SF (a, col b) (Event c) -> (col (SF a b) -> c -> SF a (col b)) -> SF a (col b)
- rpSwitchB :: Functor col => col (SF a b) -> SF (a, Event (col (SF a b) -> col (SF a b))) (col b)
- drpSwitchB :: Functor col => col (SF a b) -> SF (a, Event (col (SF a b) -> col (SF a b))) (col b)
- par :: Functor col => (forall sf. a -> col sf -> col (b, sf)) -> col (SF b c) -> SF a (col c)
- pSwitch :: Functor col => (forall sf. a -> col sf -> col (b, sf)) -> col (SF b c) -> SF (a, col c) (Event d) -> (col (SF b c) -> d -> SF a (col c)) -> SF a (col c)
- dpSwitch :: Functor col => (forall sf. a -> col sf -> col (b, sf)) -> col (SF b c) -> SF (a, col c) (Event d) -> (col (SF b c) -> d -> SF a (col c)) -> SF a (col c)
- rpSwitch :: Functor col => (forall sf. a -> col sf -> col (b, sf)) -> col (SF b c) -> SF (a, Event (col (SF b c) -> col (SF b c))) (col c)
- drpSwitch :: Functor col => (forall sf. a -> col sf -> col (b, sf)) -> col (SF b c) -> SF (a, Event (col (SF b c) -> col (SF b c))) (col c)
- old_hold :: a -> SF (Event a) a
- hold :: a -> SF (Event a) a
- dHold :: a -> SF (Event a) a
- trackAndHold :: a -> SF (Maybe a) a
- old_accum :: a -> SF (Event (a -> a)) (Event a)
- old_accumBy :: (b -> a -> b) -> b -> SF (Event a) (Event b)
- old_accumFilter :: (c -> a -> (c, Maybe b)) -> c -> SF (Event a) (Event b)
- accum :: a -> SF (Event (a -> a)) (Event a)
- accumHold :: a -> SF (Event (a -> a)) a
- dAccumHold :: a -> SF (Event (a -> a)) a
- accumBy :: (b -> a -> b) -> b -> SF (Event a) (Event b)
- accumHoldBy :: (b -> a -> b) -> b -> SF (Event a) b
- dAccumHoldBy :: (b -> a -> b) -> b -> SF (Event a) b
- accumFilter :: (c -> a -> (c, Maybe b)) -> c -> SF (Event a) (Event b)
- old_pre :: SF a a
- old_iPre :: a -> SF a a
- pre :: SF a a
- iPre :: a -> SF a a
- delay :: Time -> a -> SF a a
- integral :: VectorSpace a s => SF a a
- derivative :: VectorSpace a s => SF a a
- imIntegral :: VectorSpace a s => a -> SF a a
- loopPre :: c -> SF (a, c) (b, c) -> SF a b
- loopIntegral :: VectorSpace c s => SF (a, c) (b, c) -> SF a b
- noEvent :: Event a
- noEventFst :: (Event a, b) -> (Event c, b)
- noEventSnd :: (a, Event b) -> (a, Event c)
- event :: a -> (b -> a) -> Event b -> a
- fromEvent :: Event a -> a
- isEvent :: Event a -> Bool
- isNoEvent :: Event a -> Bool
- tag :: Event a -> b -> Event b
- tagWith :: b -> Event a -> Event b
- attach :: Event a -> b -> Event (a, b)
- lMerge :: Event a -> Event a -> Event a
- rMerge :: Event a -> Event a -> Event a
- merge :: Event a -> Event a -> Event a
- mergeBy :: (a -> a -> a) -> Event a -> Event a -> Event a
- mapMerge :: (a -> c) -> (b -> c) -> (a -> b -> c) -> Event a -> Event b -> Event c
- mergeEvents :: [Event a] -> Event a
- catEvents :: [Event a] -> Event [a]
- joinE :: Event a -> Event b -> Event (a, b)
- splitE :: Event (a, b) -> (Event a, Event b)
- filterE :: (a -> Bool) -> Event a -> Event a
- mapFilterE :: (a -> Maybe b) -> Event a -> Event b
- gate :: Event a -> Bool -> Event a
- noise :: (RandomGen g, Random b) => g -> SF a b
- noiseR :: (RandomGen g, Random b) => (b, b) -> g -> SF a b
- occasionally :: RandomGen g => g -> Time -> b -> SF a (Event b)
- reactimate :: IO a -> (Bool -> IO (DTime, Maybe a)) -> (Bool -> b -> IO Bool) -> SF a b -> IO ()
- type ReactHandle a b = IORef (ReactState a b)
- reactInit :: IO a -> (ReactHandle a b -> Bool -> b -> IO Bool) -> SF a b -> IO (ReactHandle a b)
- react :: ReactHandle a b -> (DTime, Maybe a) -> IO Bool
- type DTime = Double
- embed :: SF a b -> (a, [(DTime, Maybe a)]) -> [b]
- embedSynch :: SF a b -> (a, [(DTime, Maybe a)]) -> SF Double b
- deltaEncode :: Eq a => DTime -> [a] -> (a, [(DTime, Maybe a)])
- deltaEncodeBy :: (a -> a -> Bool) -> DTime -> [a] -> (a, [(DTime, Maybe a)])

# Documentation

module Control.Arrow

module FRP.Yampa.VectorSpace

class RandomGen g where

The class `RandomGen`

provides a common interface to random number
generators.

The `next`

operation returns an `Int`

that is uniformly distributed
in the range returned by `genRange`

(including both end points),
and a new generator.

split :: g -> (g, g)

The `split`

operation allows one to obtain two distinct random number
generators. This is very useful in functional programs (for example, when
passing a random number generator down to recursive calls), but very
little work has been done on statistically robust implementations of
`split`

([System.Random, System.Random]
are the only examples we know of).

The `genRange`

operation yields the range of values returned by
the generator.

It is required that:

The second condition ensures that `genRange`

cannot examine its
argument, and hence the value it returns can be determined only by the
instance of `RandomGen`

. That in turn allows an implementation to make
a single call to `genRange`

to establish a generator's range, without
being concerned that the generator returned by (say) `next`

might have
a different range to the generator passed to `next`

.

The default definition spans the full range of `Int`

.

class Random a where

With a source of random number supply in hand, the `Random`

class allows the
programmer to extract random values of a variety of types.

randomR :: RandomGen g => (a, a) -> g -> (a, g)

Takes a range *(lo,hi)* and a random number generator
*g*, and returns a random value uniformly distributed in the closed
interval *[lo,hi]*, together with a new generator. It is unspecified
what happens if *lo>hi*. For continuous types there is no requirement
that the values *lo* and *hi* are ever produced, but they may be,
depending on the implementation and the interval.

random :: RandomGen g => g -> (a, g)

The same as `randomR`

, but using a default range determined by the type:

randomRs :: RandomGen g => (a, a) -> g -> [a]

Plural variant of `randomR`

, producing an infinite list of
random values instead of returning a new generator.

randoms :: RandomGen g => g -> [a]

Plural variant of `random`

, producing an infinite list of
random values instead of returning a new generator.

A variant of `randomR`

that uses the global random number generator
(see System.Random).

A variant of `random`

that uses the global random number generator
(see System.Random).

repeatedly :: Time -> b -> SF a (Event b)Source

afterEachCat :: [(Time, b)] -> SF a (Event [b])Source

pSwitchB :: Functor col => col (SF a b) -> SF (a, col b) (Event c) -> (col (SF a b) -> c -> SF a (col b)) -> SF a (col b)Source

dpSwitchB :: Functor col => col (SF a b) -> SF (a, col b) (Event c) -> (col (SF a b) -> c -> SF a (col b)) -> SF a (col b)Source

rpSwitchB :: Functor col => col (SF a b) -> SF (a, Event (col (SF a b) -> col (SF a b))) (col b)Source

drpSwitchB :: Functor col => col (SF a b) -> SF (a, Event (col (SF a b) -> col (SF a b))) (col b)Source

pSwitch :: Functor col => (forall sf. a -> col sf -> col (b, sf)) -> col (SF b c) -> SF (a, col c) (Event d) -> (col (SF b c) -> d -> SF a (col c)) -> SF a (col c)Source

dpSwitch :: Functor col => (forall sf. a -> col sf -> col (b, sf)) -> col (SF b c) -> SF (a, col c) (Event d) -> (col (SF b c) -> d -> SF a (col c)) -> SF a (col c)Source

rpSwitch :: Functor col => (forall sf. a -> col sf -> col (b, sf)) -> col (SF b c) -> SF (a, Event (col (SF b c) -> col (SF b c))) (col c)Source

drpSwitch :: Functor col => (forall sf. a -> col sf -> col (b, sf)) -> col (SF b c) -> SF (a, Event (col (SF b c) -> col (SF b c))) (col c)Source

trackAndHold :: a -> SF (Maybe a) aSource

old_accumBy :: (b -> a -> b) -> b -> SF (Event a) (Event b)Source

dAccumHold :: a -> SF (Event (a -> a)) aSource

accumHoldBy :: (b -> a -> b) -> b -> SF (Event a) bSource

dAccumHoldBy :: (b -> a -> b) -> b -> SF (Event a) bSource

integral :: VectorSpace a s => SF a aSource

derivative :: VectorSpace a s => SF a aSource

imIntegral :: VectorSpace a s => a -> SF a aSource

loopIntegral :: VectorSpace c s => SF (a, c) (b, c) -> SF a bSource

noEventFst :: (Event a, b) -> (Event c, b)Source

noEventSnd :: (a, Event b) -> (a, Event c)Source

mergeEvents :: [Event a] -> Event aSource

mapFilterE :: (a -> Maybe b) -> Event a -> Event bSource

reactimate :: IO a -> (Bool -> IO (DTime, Maybe a)) -> (Bool -> b -> IO Bool) -> SF a b -> IO ()Source

type ReactHandle a b = IORef (ReactState a b)Source

reactInit :: IO a -> (ReactHandle a b -> Bool -> b -> IO Bool) -> SF a b -> IO (ReactHandle a b)Source