Yampa-0.9.3: Library for programming hybrid systems.

Portabilitynon-portable (GHC extensions)
Stabilityprovisional
Maintainernilsson@cs.yale.edu
Safe HaskellSafe-Infered

FRP.Yampa

Description

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?

Synopsis

Documentation

module Control.Arrow

module FRP.Yampa.VectorSpace

class RandomGen g where

The class RandomGen provides a common interface to random number generators.

Methods

next :: g -> (Int, g)

The next operation returns an Int that is uniformly distributed in the range returned by genRange (including both end points), and a new generator.

genRange :: g -> (Int, Int)

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.

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).

Instances

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.

Minimal complete definition: randomR and random.

Methods

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:

  • For bounded types (instances of Bounded, such as Char), the range is normally the whole type.
  • For fractional types, the range is normally the semi-closed interval [0,1).
  • For Integer, the range is (arbitrarily) the range of Int.

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.

randomRIO :: (a, a) -> IO a

A variant of randomR that uses the global random number generator (see System.Random).

randomIO :: IO a

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

Instances

(#) :: (a -> b) -> (b -> c) -> a -> cSource

dup :: a -> (a, a)Source

swap :: (a, b) -> (b, a)Source

type Time = DoubleSource

data SF a b Source

Instances

data Event a Source

Constructors

NoEvent 
Event a 

Instances

Functor Event 
Eq a => Eq (Event a) 
Ord a => Ord (Event a) 
Show a => Show (Event a) 
Forceable a => Forceable (Event a) 

arrPrim :: (a -> b) -> SF a bSource

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

identity :: SF a aSource

constant :: b -> SF a bSource

localTime :: SF a TimeSource

time :: SF a TimeSource

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

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

(-=>) :: (b -> b) -> SF a b -> SF a bSource

(>=-) :: (a -> a) -> SF a b -> SF a bSource

initially :: a -> SF a aSource

sscan :: (b -> a -> b) -> b -> SF a bSource

sscanPrim :: (c -> a -> Maybe (c, b)) -> c -> b -> SF a bSource

never :: SF a (Event b)Source

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

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

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

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

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

delayEvent :: Time -> SF (Event a) (Event a)Source

delayEventCat :: Time -> SF (Event a) (Event [a])Source

edge :: SF Bool (Event ())Source

iEdge :: Bool -> SF Bool (Event ())Source

edgeTag :: a -> SF Bool (Event a)Source

edgeJust :: SF (Maybe a) (Event a)Source

edgeBy :: (a -> a -> Maybe b) -> a -> SF a (Event b)Source

notYet :: SF (Event a) (Event a)Source

once :: SF (Event a) (Event a)Source

takeEvents :: Int -> SF (Event a) (Event a)Source

dropEvents :: Int -> SF (Event a) (Event a)Source

switch :: SF a (b, Event c) -> (c -> SF a b) -> SF a bSource

dSwitch :: SF a (b, Event c) -> (c -> SF a b) -> SF a bSource

rSwitch :: SF a b -> SF (a, Event (SF a b)) bSource

drSwitch :: SF a b -> SF (a, Event (SF a b)) bSource

kSwitch :: SF a b -> SF (a, b) (Event c) -> (SF a b -> c -> SF a b) -> SF a bSource

dkSwitch :: SF a b -> SF (a, b) (Event c) -> (SF a b -> c -> SF a b) -> SF a bSource

parB :: Functor col => col (SF a b) -> SF a (col 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

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

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

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

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

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

old_accum :: a -> SF (Event (a -> a)) (Event a)Source

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

old_accumFilter :: (c -> a -> (c, Maybe b)) -> c -> SF (Event a) (Event b)Source

accum :: a -> SF (Event (a -> a)) (Event a)Source

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

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

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

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

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

accumFilter :: (c -> a -> (c, Maybe b)) -> c -> SF (Event a) (Event b)Source

old_pre :: SF a aSource

old_iPre :: a -> SF a aSource

pre :: SF a aSource

iPre :: a -> SF a aSource

delay :: Time -> a -> SF a aSource

integral :: VectorSpace a s => SF a aSource

derivative :: VectorSpace a s => SF a aSource

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

loopPre :: c -> SF (a, c) (b, c) -> SF a bSource

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

noEvent :: Event aSource

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

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

event :: a -> (b -> a) -> Event b -> aSource

fromEvent :: Event a -> aSource

isEvent :: Event a -> BoolSource

isNoEvent :: Event a -> BoolSource

tag :: Event a -> b -> Event bSource

tagWith :: b -> Event a -> Event bSource

attach :: Event a -> b -> Event (a, b)Source

lMerge :: Event a -> Event a -> Event aSource

rMerge :: Event a -> Event a -> Event aSource

merge :: Event a -> Event a -> Event aSource

mergeBy :: (a -> a -> a) -> Event a -> Event a -> Event aSource

mapMerge :: (a -> c) -> (b -> c) -> (a -> b -> c) -> Event a -> Event b -> Event cSource

mergeEvents :: [Event a] -> Event aSource

catEvents :: [Event a] -> Event [a]Source

joinE :: Event a -> Event b -> Event (a, b)Source

splitE :: Event (a, b) -> (Event a, Event b)Source

filterE :: (a -> Bool) -> Event a -> Event aSource

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

gate :: Event a -> Bool -> Event aSource

noise :: (RandomGen g, Random b) => g -> SF a bSource

noiseR :: (RandomGen g, Random b) => (b, b) -> g -> SF a bSource

occasionally :: RandomGen g => g -> Time -> b -> SF a (Event b)Source

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

react :: ReactHandle a b -> (DTime, Maybe a) -> IO BoolSource

type DTime = DoubleSource

embed :: SF a b -> (a, [(DTime, Maybe a)]) -> [b]Source

embedSynch :: SF a b -> (a, [(DTime, Maybe a)]) -> SF Double bSource

deltaEncode :: Eq a => DTime -> [a] -> (a, [(DTime, Maybe a)])Source

deltaEncodeBy :: (a -> a -> Bool) -> DTime -> [a] -> (a, [(DTime, Maybe a)])Source