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Fix warnings
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‎src/Control/Monad/Aff.purs‎

Lines changed: 161 additions & 165 deletions
Original file line numberDiff line numberDiff line change
@@ -19,210 +19,206 @@ module Control.Monad.Aff
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)
2020
where
2121

22-
import Prelude
23-
24-
import Control.Alt(Alt)
25-
import Control.Alternative(Alternative)
26-
import Control.Monad.Cont.Class(MonadCont)
27-
import Control.Monad.Eff(Eff())
28-
import Control.Monad.Eff.Class(MonadEff, liftEff)
29-
import Control.Monad.Eff.Exception(Error(), EXCEPTION(), catchException, throwException, error)
30-
import Control.Monad.Eff.Unsafe(unsafeInterleaveEff)
31-
import Control.Monad.Error.Class(MonadError, throwError)
32-
import Control.Monad.Rec.Class(MonadRec, tailRecM)
33-
import Control.MonadPlus(MonadPlus)
34-
import Control.Plus(Plus)
35-
36-
import Data.Either(Either(..), either)
37-
import Data.Function(Fn2(), Fn3(), runFn2, runFn3)
38-
import Data.Monoid(Monoid, mempty)
39-
40-
-- | An asynchronous computation with effects `e`. The computation either
41-
-- | errors or produces a value of type `a`.
42-
-- |
43-
-- | This is moral equivalent of `ErrorT (ContT Unit (Eff e)) a`.
44-
foreign import data Aff :: # ! -> * -> *
45-
46-
-- | A pure asynchronous computation, having no effects other than
47-
-- | asynchronous computation.
48-
type PureAff a = forall e. Aff e a
49-
50-
-- | A canceler is asynchronous function that can be used to attempt the
51-
-- | cancelation of a computation. Returns a boolean flag indicating whether
52-
-- | or not the cancellation was successful. Many computations may be composite,
53-
-- | in such cases the flag indicates whether any part of the computation was
54-
-- | successfully canceled. The flag should not be used for communication.
55-
newtype Canceler e = Canceler (Error -> Aff e Boolean)
56-
57-
-- | Unwraps the canceler function from the newtype that wraps it.
58-
cancel :: forall e. Canceler e -> Error -> Aff e Boolean
59-
cancel (Canceler f) = f
60-
61-
-- | This function allows you to attach a custom canceler to an asynchronous
62-
-- | computation. If the computation is canceled, then the custom canceler
63-
-- | will be run along side the computation's own canceler.
64-
cancelWith :: forall e a. Aff e a -> Canceler e -> Aff e a
65-
cancelWith aff c = runFn3 _cancelWith nonCanceler aff c
66-
67-
-- | Converts the asynchronous computation into a synchronous one. All values
68-
-- | are ignored, and if the computation produces an error, it is thrown.
69-
-- |
70-
-- | Catching exceptions by using `catchException` with the resulting Eff
71-
-- | computation is not recommended, as exceptions may end up being thrown
72-
-- | asynchronously, in which case they cannot be caught.
73-
-- |
74-
-- | If you do need to handle exceptions, you can use `runAff` instead, or
75-
-- | you can handle the exception within the Aff computation, using
76-
-- | `catchError` (or any of the other mechanisms).
77-
launchAff :: forall e a. Aff e a -> Eff (err :: EXCEPTION | e) Unit
78-
launchAff = runAff throwException (const (pure unit)) <<< liftEx
79-
where
80-
liftEx :: forall e a. Aff e a -> Aff (err :: EXCEPTION | e) a
81-
liftEx = _unsafeInterleaveAff
82-
83-
-- | Runs the asynchronous computation. You must supply an error callback and a
84-
-- | success callback.
85-
runAff :: forall e a. (Error -> Eff e Unit) -> (a -> Eff e Unit) -> Aff e a -> Eff e Unit
86-
runAff ex f aff = runFn3 _runAff ex f aff
87-
88-
-- | Creates an asynchronous effect from a function that accepts error and
89-
-- | success callbacks. This function can be used for asynchronous computations
90-
-- | that cannot be canceled.
91-
makeAff :: forall e a. ((Error -> Eff e Unit) -> (a -> Eff e Unit) -> Eff e Unit) -> Aff e a
92-
makeAff h = makeAff' (\e a -> const nonCanceler <$> h e a)
93-
94-
-- | Creates an asynchronous effect from a function that accepts error and
95-
-- | success callbacks, and returns a canceler for the computation. This
96-
-- | function can be used for asynchronous computations that can be canceled.
97-
makeAff' :: forall e a. ((Error -> Eff e Unit) -> (a -> Eff e Unit) -> Eff e (Canceler e)) -> Aff e a
98-
makeAff' h = _makeAff h
22+
import Prelude
23+
24+
import Control.Alt (Alt)
25+
import Control.Alternative (Alternative)
26+
import Control.Monad.Cont.Class (MonadCont)
27+
import Control.Monad.Eff (Eff())
28+
import Control.Monad.Eff.Class (MonadEff)
29+
import Control.Monad.Eff.Exception (Error(), EXCEPTION(), throwException, error)
30+
import Control.Monad.Error.Class (MonadError, throwError)
31+
import Control.Monad.Rec.Class (MonadRec, tailRecM)
32+
import Control.MonadPlus (MonadPlus)
33+
import Control.Plus (Plus)
34+
35+
import Data.Either (Either(..), either)
36+
import Data.Function (Fn2(), Fn3(), runFn2, runFn3)
37+
import Data.Monoid (Monoid, mempty)
38+
39+
-- | An asynchronous computation with effects `e`. The computation either
40+
-- | errors or produces a value of type `a`.
41+
-- |
42+
-- | This is moral equivalent of `ErrorT (ContT Unit (Eff e)) a`.
43+
foreign import data Aff :: # ! -> * -> *
44+
45+
-- | A pure asynchronous computation, having no effects other than
46+
-- | asynchronous computation.
47+
type PureAff a = forall e. Aff e a
48+
49+
-- | A canceler is asynchronous function that can be used to attempt the
50+
-- | cancelation of a computation. Returns a boolean flag indicating whether
51+
-- | or not the cancellation was successful. Many computations may be composite,
52+
-- | in such cases the flag indicates whether any part of the computation was
53+
-- | successfully canceled. The flag should not be used for communication.
54+
newtype Canceler e = Canceler (Error -> Aff e Boolean)
55+
56+
-- | Unwraps the canceler function from the newtype that wraps it.
57+
cancel :: forall e. Canceler e -> Error -> Aff e Boolean
58+
cancel (Canceler f) = f
59+
60+
-- | This function allows you to attach a custom canceler to an asynchronous
61+
-- | computation. If the computation is canceled, then the custom canceler
62+
-- | will be run along side the computation's own canceler.
63+
cancelWith :: forall e a. Aff e a -> Canceler e -> Aff e a
64+
cancelWith aff c = runFn3 _cancelWith nonCanceler aff c
65+
66+
-- | Converts the asynchronous computation into a synchronous one. All values
67+
-- | are ignored, and if the computation produces an error, it is thrown.
68+
-- |
69+
-- | Catching exceptions by using `catchException` with the resulting Eff
70+
-- | computation is not recommended, as exceptions may end up being thrown
71+
-- | asynchronously, in which case they cannot be caught.
72+
-- |
73+
-- | If you do need to handle exceptions, you can use `runAff` instead, or
74+
-- | you can handle the exception within the Aff computation, using
75+
-- | `catchError` (or any of the other mechanisms).
76+
launchAff :: forall e a. Aff e a -> Eff (err :: EXCEPTION | e) Unit
77+
launchAff = runAff throwException (const (pure unit)) <<< liftEx
78+
where
79+
liftEx :: Aff e a -> Aff (err :: EXCEPTION | e) a
80+
liftEx = _unsafeInterleaveAff
9981

100-
-- | Runs the asynchronous computation off the current execution context.
101-
later :: forall e a. Aff e a -> Aff e a
102-
later = later' 0
82+
-- | Runs the asynchronous computation. You must supply an error callback and a
83+
-- | success callback.
84+
runAff :: forall e a. (Error -> Eff e Unit) -> (a -> Eff e Unit) -> Aff e a -> Eff e Unit
85+
runAff ex f aff = runFn3 _runAff ex f aff
10386

104-
-- | Runs the specified asynchronous computation later, by the specified
105-
-- | number of milliseconds.
106-
later' :: forall e a. Int -> Aff e a -> Aff e a
107-
later' n aff = runFn3 _setTimeout nonCanceler n aff
87+
-- | Creates an asynchronous effect from a function that accepts error and
88+
-- | success callbacks. This function can be used for asynchronous computations
89+
-- | that cannot be canceled.
90+
makeAff :: forall e a. ((Error -> Eff e Unit) -> (a -> Eff e Unit) -> Eff e Unit) -> Aff e a
91+
makeAff h = makeAff' (\e a -> const nonCanceler <$> h e a)
10892

109-
-- | Compute `aff1`, followed by `aff2` regardless of whether `aff1` terminated successfully.
110-
finally :: forall e a b. Aff e a -> Aff e b -> Aff e a
111-
finally aff1 aff2 = do
112-
x <- attempt aff1
113-
aff2
114-
either throwError pure x
93+
-- | Creates an asynchronous effect from a function that accepts error and
94+
-- | success callbacks, and returns a canceler for the computation. This
95+
-- | function can be used for asynchronous computations that can be canceled.
96+
makeAff' :: forall e a. ((Error -> Eff e Unit) -> (a -> Eff e Unit) -> Eff e (Canceler e)) -> Aff e a
97+
makeAff' h = _makeAff h
11598

116-
-- | Forks the specified asynchronous computation so subsequent computations
117-
-- | will not block on the result of the computation.
118-
-- |
119-
-- | Returns a canceler that can be used to attempt cancellation of the
120-
-- | forked computation.
121-
forkAff :: forall e a. Aff e a -> Aff e (Canceler e)
122-
forkAff aff = runFn2 _forkAff nonCanceler aff
99+
-- | Runs the asynchronous computation off the current execution context.
100+
later :: forall e a. Aff e a -> Aff e a
101+
later = later' 0
123102

124-
-- | Promotes any error to the value level of the asynchronous monad.
125-
attempt :: forall e a. Aff e a -> Aff e (Either Error a)
126-
attempt aff = runFn3 _attempt Left Right aff
103+
-- | Runs the specified asynchronous computation later, by the specified
104+
-- | number of milliseconds.
105+
later' :: forall e a. Int -> Aff e a -> Aff e a
106+
later' n aff = runFn3 _setTimeout nonCanceler n aff
127107

128-
-- | Ignores any errors.
129-
apathize :: forall e a. Aff e a -> Aff e Unit
130-
apathize a = const unit <$> attempt a
108+
-- | Compute `aff1`, followed by `aff2` regardless of whether `aff1` terminated successfully.
109+
finally :: forall e a b. Aff e a -> Aff e b -> Aff e a
110+
finally aff1 aff2 = do
111+
x <- attempt aff1
112+
aff2
113+
either throwError pure x
131114

132-
-- | Lifts a synchronous computation and makes explicit any failure from exceptions.
133-
liftEff' :: forall e a. Eff (err :: EXCEPTION | e) a -> Aff e (Either Error a)
134-
liftEff' eff = attempt (_unsafeInterleaveAff (runFn2 _liftEff nonCanceler eff))
115+
-- | Forks the specified asynchronous computation so subsequent computations
116+
-- | will not block on the result of the computation.
117+
-- |
118+
-- | Returns a canceler that can be used to attempt cancellation of the
119+
-- | forked computation.
120+
forkAff :: forall e a. Aff e a -> Aff e (Canceler e)
121+
forkAff aff = runFn2 _forkAff nonCanceler aff
135122

136-
-- | A constant canceller that always returns false.
137-
nonCanceler :: forall e. Canceler e
138-
nonCanceler = Canceler (const (pure false))
123+
-- | Promotes any error to the value level of the asynchronous monad.
124+
attempt :: forall e a. Aff e a -> Aff e (Either Error a)
125+
attempt aff = runFn3 _attempt Left Right aff
139126

140-
-- | A constant canceller that always returns true.
141-
alwaysCanceler :: forall e. Canceler e
142-
alwaysCanceler = Canceler (const (pure true))
127+
-- | Ignores any errors.
128+
apathize :: forall e a. Aff e a -> Aff e Unit
129+
apathize a = const unit <$> attempt a
143130

144-
instance semigroupAff :: (Semigroup a) => Semigroup (Aff e a) where
145-
append a b = (<>) <$> a <*> b
131+
-- | Lifts a synchronous computation and makes explicit any failure from exceptions.
132+
liftEff' :: forall e a. Eff (err :: EXCEPTION | e) a -> Aff e (Either Error a)
133+
liftEff' eff = attempt (_unsafeInterleaveAff (runFn2 _liftEff nonCanceler eff))
146134

147-
instance monoidAff :: (Monoid a) => Monoid (Aff e a) where
148-
mempty = pure mempty
135+
-- | A constant canceller that always returns false.
136+
nonCanceler :: forall e. Canceler e
137+
nonCanceler = Canceler (const (pure false))
149138

150-
instance functorAff :: Functor (Aff e) where
151-
map f fa = runFn2 _fmap f fa
139+
-- | A constant canceller that always returns true.
140+
alwaysCanceler :: forall e. Canceler e
141+
alwaysCanceler = Canceler (const (pure true))
152142

153-
instance applyAff :: Apply (Aff e) where
154-
apply ff fa = runFn3 _bind alwaysCanceler ff (\f -> f <$> fa)
143+
instance semigroupAff :: (Semigroup a) => Semigroup (Aff e a) where
144+
append a b = (<>) <$> a <*> b
155145

156-
instance applicativeAff :: Applicative (Aff e) where
157-
pure v = runFn2 _pure nonCanceler v
146+
instance monoidAff :: (Monoid a) => Monoid (Aff e a) where
147+
mempty = pure mempty
158148

159-
instance bindAff :: Bind (Aff e) where
160-
bind fa f = runFn3 _bind alwaysCanceler fa f
149+
instance functorAff :: Functor (Aff e) where
150+
map f fa = runFn2 _fmap f fa
161151

162-
instance monadAff :: Monad (Aff e)
152+
instance applyAff :: Apply (Aff e) where
153+
apply ff fa = runFn3 _bind alwaysCanceler ff (\f -> f <$> fa)
163154

164-
instance monadEffAff :: MonadEff e (Aff e) where
165-
liftEff eff = runFn2 _liftEff nonCanceler eff
155+
instance applicativeAff :: Applicative (Aff e) where
156+
pure v = runFn2 _pure nonCanceler v
166157

167-
-- | Allows users to catch and throw errors on the error channel of the
168-
-- | asynchronous computation. See documentation in `purescript-transformers`.
169-
instance monadErrorAff :: MonadError Error (Aff e) where
170-
throwError e = runFn2 _throwError nonCanceler e
158+
instance bindAff :: Bind (Aff e) where
159+
bind fa f = runFn3 _bind alwaysCanceler fa f
171160

172-
catchError aff ex = attempt aff >>= either ex pure
161+
instance monadAff :: Monad (Aff e)
173162

174-
instance altAff :: Alt (Aff e) where
175-
alt a1 a2 = attempt a1 >>= either (const a2) pure
163+
instance monadEffAff :: MonadEff e (Aff e) where
164+
liftEff eff = runFn2 _liftEff nonCanceler eff
176165

177-
instance plusAff :: Plus (Aff e) where
178-
empty = throwError $ error "Always fails"
166+
-- | Allows users to catch and throw errors on the error channel of the
167+
-- | asynchronous computation. See documentation in `purescript-transformers`.
168+
instance monadErrorAff :: MonadError Error (Aff e) where
169+
throwError e = runFn2 _throwError nonCanceler e
179170

180-
instance alternativeAff :: Alternative (Aff e)
171+
catchError aff ex = attempt aff >>= either ex pure
181172

182-
instance monadPlusAff :: MonadPlus (Aff e)
173+
instance altAff :: Alt (Aff e) where
174+
alt a1 a2 = attempt a1 >>= either (const a2) pure
183175

184-
instance monadRecAff :: MonadRec (Aff e) where
185-
tailRecM f a = go 0 f a
186-
where
187-
go size f a = do
188-
e <- f a
189-
case e of
190-
Left a' | size < 100 -> go (size + 1) f a'
191-
| otherwise -> later (tailRecM f a')
192-
Right b -> pure b
176+
instance plusAff :: Plus (Aff e) where
177+
empty = throwError $ error "Always fails"
193178

194-
instance monadContAff :: MonadCont (Aff e) where
195-
callCC f = makeAff (\eb cb -> runAff eb cb (f \a -> makeAff (\_ _ -> cb a)))
179+
instance alternativeAff :: Alternative (Aff e)
196180

197-
instance semigroupCanceler :: Semigroup (Canceler e) where
198-
append (Canceler f1) (Canceler f2) = Canceler (\e -> (||) <$> f1 e <*> f2 e)
181+
instance monadPlusAff :: MonadPlus (Aff e)
199182

200-
instance monoidCanceler :: Monoid (Canceler e) where
201-
mempty = Canceler (const (pure true))
183+
instance monadRecAff :: MonadRec (Aff e) where
184+
tailRecM f a = go 0 f a
185+
where
186+
go size f a = do
187+
e <- f a
188+
case e of
189+
Left a' | size < 100 -> go (size + 1) f a'
190+
| otherwise -> later (tailRecM f a')
191+
Right b -> pure b
202192

203-
foreign import _cancelWith :: forall e a. Fn3 (Canceler e) (Aff e a) (Canceler e) (Aff e a)
193+
instance monadContAff :: MonadCont (Aff e) where
194+
callCC f = makeAff (\eb cb -> runAff eb cb (f \a -> makeAff (\_ _ -> cb a)))
204195

205-
foreign import _setTimeout :: forall e a. Fn3 (Canceler e) Int (Aff e a) (Aff e a)
196+
instance semigroupCanceler :: Semigroup (Canceler e) where
197+
append (Canceler f1) (Canceler f2) = Canceler (\e -> (||) <$> f1 e <*> f2 e)
206198

207-
foreign import _unsafeInterleaveAff :: forall e1 e2 a. Aff e1 a -> Aff e2 a
199+
instance monoidCanceler :: Monoid (Canceler e) where
200+
mempty = Canceler (const (pure true))
208201

209-
foreign import _forkAff :: forall e a. Fn2 (Canceler e) (Aff e a) (Aff e (Canceler e))
202+
foreign import _cancelWith :: forall e a. Fn3 (Canceler e) (Aff e a) (Canceler e) (Aff e a)
210203

211-
foreign import _makeAff :: forall e a. ((Error -> Eff e Unit) -> (a -> Eff e Unit) -> Eff e (Canceler e)) -> Aff e a
204+
foreign import _setTimeout :: forall e a. Fn3 (Canceler e) Int (Aff e a) (Aff e a)
212205

213-
foreign import _pure :: forall e a. Fn2 (Canceler e) a (Aff e a)
206+
foreign import _unsafeInterleaveAff :: forall e1 e2 a. Aff e1 a -> Aff e2 a
214207

215-
foreign import _throwError :: forall e a. Fn2 (Canceler e) Error (Aff e a)
208+
foreign import _forkAff :: forall e a. Fn2 (Canceler e) (Aff e a) (Aff e (Canceler e))
216209

217-
foreign import _fmap :: forall e a b. Fn2 (a -> b) (Aff e a) (Aff e b)
210+
foreign import _makeAff :: forall e a. ((Error -> Eff e Unit) -> (a -> Eff e Unit) -> Eff e (Canceler e)) -> Aff e a
218211

219-
foreign import _bind :: forall e a b. Fn3 (Canceler e) (Aff e a) (a -> Aff e b) (Aff e b)
212+
foreign import _pure :: forall e a. Fn2 (Canceler e) a (Aff e a)
220213

221-
foreign import _attempt :: forall e a. Fn3 (forall x y. x -> Either x y) (forall x y. y -> Either x y) (Aff e a) (Aff e (Either Error a))
214+
foreign import _throwError :: forall e a. Fn2 (Canceler e) Error (Aff e a)
222215

223-
foreign import _runAff :: forall e a. Fn3 (Error -> Eff e Unit) (a -> Eff e Unit) (Aff e a) (Eff e Unit)
216+
foreign import _fmap :: forall e a b. Fn2 (a -> b) (Aff e a) (Aff e b)
224217

225-
foreign import _liftEff :: forall e a. Fn2 (Canceler e) (Eff e a) (Aff e a)
218+
foreign import _bind :: forall e a b. Fn3 (Canceler e) (Aff e a) (a -> Aff e b) (Aff e b)
226219

220+
foreign import _attempt :: forall e a. Fn3 (forall x y. x -> Either x y) (forall x y. y -> Either x y) (Aff e a) (Aff e (Either Error a))
227221

222+
foreign import _runAff :: forall e a. Fn3 (Error -> Eff e Unit) (a -> Eff e Unit) (Aff e a) (Eff e Unit)
228223

224+
foreign import _liftEff :: forall e a. Fn2 (Canceler e) (Eff e a) (Aff e a)

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