src/RMCA/Auxiliary.hs

   1 {-# LANGUAGE Arrows, FlexibleContexts, MultiParamTypeClasses #-}
   2
   3 module RMCA.Auxiliary where
   4
   5 import Control.Monad
   6 import Data.CBMVar
   7 import Data.Fixed
   8 import Data.Maybe
   9 import Data.ReactiveValue
  10 import FRP.Yampa
  11
  12 --------------------------------------------------------------------------------
  13 -- General functions
  14 --------------------------------------------------------------------------------
  15
  16 (<$$>) :: (Functor f) => f a -> (a -> b) -> f b
  17 (<$$>) = flip (<$>)
  18
  19 ($>) :: (Functor f) => f a -> b -> f b
  20 ($>) = flip (<$)
  21
  22 bound :: (Ord a) => (a, a) -> a -> a
  23 bound (min, max) x
  24   | x < min = min
  25   | x > max = max
  26   | otherwise = x
  27
  28 fromMaybeM_ :: (Monad m) => Maybe (m ()) -> m ()
  29 fromMaybeM_ = fromMaybe (return ())
  30
  31 safeHead :: [a] -> Maybe a
  32 safeHead [] = Nothing
  33 safeHead (x:_) = Just x
  34
  35 safeTail :: [a] -> [a]
  36 safeTail [] = []
  37 safeTail (_:xs) = xs
  38
  39 maybeToEvent :: Maybe a -> Event a
  40 maybeToEvent Nothing = NoEvent
  41 maybeToEvent (Just x) = Event x
  42
  43 eventToMaybe :: Event a -> Maybe a
  44 eventToMaybe NoEvent = Nothing
  45 eventToMaybe (Event x) = Just x
  46
  47 eventToList :: Event [a] -> [a]
  48 eventToList NoEvent = []
  49 eventToList (Event x) = x
  50
  51 --------------------------------------------------------------------------------
  52 -- FRP
  53 --------------------------------------------------------------------------------
  54
  55 -- stepBack contains its previous argument as its output. Because it's
  56 -- hard to define it at time 0, it's wrapped up in a Maybe.
  57 stepBack :: SF a (Maybe a)
  58 stepBack = sscan f (Nothing, Nothing) >>^ snd
  59   where f :: (Maybe a, Maybe a) -> a -> (Maybe a, Maybe a)
  60         f (Nothing,_) x' = (Just x', Nothing)
  61         f (Just x, _) x' = (Just x', Just x)
  62
  63 -- Just like stepBack but the output value is always defined and is
  64 -- equal to the input at time 0.
  65 stepBack' :: SF a a
  66 stepBack' = proc x -> do
  67   x' <- stepBack -< x
  68   returnA -< fromMaybe x x'
  69
  70 -- Throws an Event when the incoming signal change. The Event is
  71 -- tagged with the new value.
  72 onChange :: (Eq a) => SF a (Event a)
  73 onChange = proc x -> do
  74   x' <- stepBack -< x
  75   let makeEvent x x'
  76         | isNothing x' = NoEvent
  77         | otherwise = let x'' = fromJust x' in
  78             if x'' == x then NoEvent else Event x
  79   returnA -< makeEvent x x'
  80
  81 varFreqSine :: SF DTime Double
  82 varFreqSine = sin ^<< (2*pi*) ^<< (`mod'` 1) ^<< integral <<^ (1/)
  83
  84 repeatedlyS :: a -> SF DTime (Event a)
  85 repeatedlyS x = edgeBy (\a b -> if a * b < 0 then Just x else Nothing) 0
  86                 <<< varFreqSine <<^ (2*)
  87
  88 -- Similar to onChange but contains its initial value in the first
  89 -- event.
  90 onChange' :: (Eq a) => SF a (Event a)
  91 onChange' = proc x -> do
  92   x' <- stepBack -< x
  93   -- If it's the first value, throw an Event, else behave like onChange.
  94   let makeEvent x x'
  95         | isNothing x' = Event x
  96         | otherwise = let x'' = fromJust x' in
  97             if x'' == x then NoEvent else Event x
  98   returnA -< makeEvent x x'
  99
 100 updateRV :: (ReactiveValueReadWrite a b m) => a -> m ()
 101 updateRV rv = reactiveValueRead rv >>= reactiveValueWrite rv
 102
 103 --------------------------------------------------------------------------------
 104 -- Reactive Values
 105 --------------------------------------------------------------------------------
 106
 107 newCBMVarRW :: a -> IO (ReactiveFieldReadWrite IO a)
 108 newCBMVarRW val = do
 109   mvar <- newCBMVar val
 110   let getter = readCBMVar mvar
 111       setter = writeCBMVar mvar
 112       notifier = installCallbackCBMVar mvar
 113   return $ ReactiveFieldReadWrite setter getter notifier
 114
 115 reactiveValueAppend :: (Monoid b, ReactiveValueReadWrite a b m) =>
 116                        a -> b -> m ()
 117 reactiveValueAppend rv v = do ov <- reactiveValueRead rv
 118                               reactiveValueWrite rv (ov `mappend` v)
 119
 120 reactiveValueEmpty :: (Monoid b, ReactiveValueReadWrite a b m) =>
 121                       a -> m ()
 122 reactiveValueEmpty rv = reactiveValueWrite rv mempty
 123
 124 reactiveValueWriteOnNotEq :: ( Eq b
 125                              , ReactiveValueReadWrite a b m) =>
 126                              a -> b -> m ()
 127 reactiveValueWriteOnNotEq rv nv = do
 128   ov <- reactiveValueRead rv
 129   when (ov /= nv) $ reactiveValueWrite rv nv
 130
 131 -- Update when the value is an Event. It would be nice to have that
 132 -- even for Maybe as well.
 133 (>:>) :: (ReactiveValueRead a (Event b) IO, ReactiveValueWrite c b IO) =>
 134          a -> c -> IO ()
 135 eventRV >:> rv = reactiveValueOnCanRead eventRV syncOnEvent
 136   where  syncOnEvent = do
 137            erv <- reactiveValueRead eventRV
 138            when (isEvent erv) $ reactiveValueWrite rv $ fromEvent erv
 139
 140 syncRightOnLeftWithBoth :: ( ReactiveValueRead a b m
 141                            , ReactiveValueReadWrite c d m
 142                            ) => (b -> d -> d) -> a -> c -> m ()
 143 syncRightOnLeftWithBoth f l r = reactiveValueOnCanRead l $ do
 144   nl <- reactiveValueRead l
 145   or <- reactiveValueRead r
 146   reactiveValueWrite r (f nl or)
 147
 148 liftW3 :: ( Monad m
 149           , ReactiveValueWrite a b m
 150           , ReactiveValueWrite c d m
 151           , ReactiveValueWrite e f m) =>
 152           (i -> (b,d,f)) -> a -> c -> e -> ReactiveFieldWrite m i
 153 liftW3 f a b c = ReactiveFieldWrite setter
 154   where setter x = do
 155           let (x1,x2,x3) = f x
 156           reactiveValueWrite a x1
 157           reactiveValueWrite b x2
 158           reactiveValueWrite c x3
 159
 160 liftRW3 :: ( ReactiveValueReadWrite a b m
 161            , ReactiveValueReadWrite c d m
 162            , ReactiveValueReadWrite e f m) =>
 163            BijectiveFunc i (b,d,f) -> a -> c -> e -> ReactiveFieldReadWrite m i
 164 liftRW3 bij a b c =
 165   ReactiveFieldReadWrite setter getter notifier
 166   where ReactiveFieldRead getter notifier = liftR3 (curry3 f2) a b c
 167         ReactiveFieldWrite setter = liftW3 f1 a b c
 168         (f1, f2) = (direct bij, inverse bij)
 169
 170 liftR4 :: ( ReactiveValueRead a b m
 171           , ReactiveValueRead c d m
 172           , ReactiveValueRead e f m
 173           , ReactiveValueRead g h m) =>
 174           (b -> d -> f -> h -> i) -> a -> c -> e -> g -> ReactiveFieldRead m i
 175 liftR4 f a b c d = ReactiveFieldRead getter notifier
 176   where getter = do
 177           x1 <- reactiveValueRead a
 178           x2 <- reactiveValueRead b
 179           x3 <- reactiveValueRead c
 180           x4 <- reactiveValueRead d
 181           return $ f x1 x2 x3 x4
 182         notifier p = do
 183           reactiveValueOnCanRead a p
 184           reactiveValueOnCanRead b p
 185           reactiveValueOnCanRead c p
 186           reactiveValueOnCanRead d p
 187
 188 liftW4 :: ( Monad m
 189           , ReactiveValueWrite a b m
 190           , ReactiveValueWrite c d m
 191           , ReactiveValueWrite e f m
 192           , ReactiveValueWrite g h m) =>
 193           (i -> (b,d,f,h)) -> a -> c -> e -> g -> ReactiveFieldWrite m i
 194 liftW4 f a b c d = ReactiveFieldWrite setter
 195   where setter x = do
 196           let (x1,x2,x3,x4) = f x
 197           reactiveValueWrite a x1
 198           reactiveValueWrite b x2
 199           reactiveValueWrite c x3
 200           reactiveValueWrite d x4
 201
 202 liftRW4 :: ( ReactiveValueReadWrite a b m
 203            , ReactiveValueReadWrite c d m
 204            , ReactiveValueReadWrite e f m
 205            , ReactiveValueReadWrite g h m) =>
 206            BijectiveFunc i (b,d,f,h) -> a -> c -> e -> g
 207         -> ReactiveFieldReadWrite m i
 208 liftRW4 bij a b c d =
 209   ReactiveFieldReadWrite setter getter notifier
 210   where ReactiveFieldRead getter notifier = liftR4 (curry4 f2) a b c d
 211         ReactiveFieldWrite setter = liftW4 f1 a b c d
 212         (f1, f2) = (direct bij, inverse bij)
 213
 214 liftR5 :: ( ReactiveValueRead a b m
 215           , ReactiveValueRead c d m
 216           , ReactiveValueRead e f m
 217           , ReactiveValueRead g h m
 218           , ReactiveValueRead i j m) =>
 219           (b -> d -> f -> h -> j -> k) -> a -> c -> e -> g -> i
 220        -> ReactiveFieldRead m k
 221 liftR5 f a b c d e = ReactiveFieldRead getter notifier
 222   where getter = do
 223           x1 <- reactiveValueRead a
 224           x2 <- reactiveValueRead b
 225           x3 <- reactiveValueRead c
 226           x4 <- reactiveValueRead d
 227           x5 <- reactiveValueRead e
 228           return $ f x1 x2 x3 x4 x5
 229         notifier p = do
 230           reactiveValueOnCanRead a p
 231           reactiveValueOnCanRead b p
 232           reactiveValueOnCanRead c p
 233           reactiveValueOnCanRead d p
 234           reactiveValueOnCanRead e p
 235
 236 liftW5 :: ( Monad m
 237           , ReactiveValueWrite a b m
 238           , ReactiveValueWrite c d m
 239           , ReactiveValueWrite e f m
 240           , ReactiveValueWrite g h m
 241           , ReactiveValueWrite i j m) =>
 242           (k -> (b,d,f,h,j)) -> a -> c -> e -> g -> i -> ReactiveFieldWrite m k
 243 liftW5 f a b c d e = ReactiveFieldWrite setter
 244   where setter x = do
 245           let (x1,x2,x3,x4,x5) = f x
 246           reactiveValueWrite a x1
 247           reactiveValueWrite b x2
 248           reactiveValueWrite c x3
 249           reactiveValueWrite d x4
 250           reactiveValueWrite e x5
 251
 252 liftRW5 :: ( ReactiveValueReadWrite a b m
 253            , ReactiveValueReadWrite c d m
 254            , ReactiveValueReadWrite e f m
 255            , ReactiveValueReadWrite g h m
 256            , ReactiveValueReadWrite i j m) =>
 257            BijectiveFunc k (b,d,f,h,j) -> a -> c -> e -> g -> i
 258         -> ReactiveFieldReadWrite m k
 259 liftRW5 bij a b c d e =
 260   ReactiveFieldReadWrite setter getter notifier
 261   where ReactiveFieldRead getter notifier = liftR5 (curry5 f2) a b c d e
 262         ReactiveFieldWrite setter = liftW5 f1 a b c d e
 263         (f1, f2) = (direct bij, inverse bij)
 264
 265 --------------------------------------------------------------------------------
 266 -- Curry and uncurry functions
 267 --------------------------------------------------------------------------------
 268
 269 curry3 :: ((a,b,c) -> d) -> a -> b -> c -> d
 270 curry3 f a b c = f (a,b,c)
 271
 272 uncurry3 :: (a -> b -> c -> d) -> (a,b,c) -> d
 273 uncurry3 f (a,b,c) = f a b c
 274
 275 curry4 :: ((a,b,c,d) -> e) -> a -> b -> c -> d -> e
 276 curry4 f a b c d = f (a,b,c,d)
 277
 278 uncurry4 :: (a -> b -> c -> d -> e) -> (a,b,c,d) -> e
 279 uncurry4 f (a,b,c,d) = f a b c d
 280
 281 curry5 :: ((a,b,c,d,e) -> f) -> a -> b -> c -> d -> e -> f
 282 curry5 f a b c d e = f (a,b,c,d,e)
 283
 284 uncurry5 :: (a -> b -> c -> d -> e -> f) -> (a,b,c,d,e) -> f
 285 uncurry5 f (a,b,c,d,e) = f a b c d e