quox/lib/Quox/EffExtra.idr

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module Quox.EffExtra
import public Control.Eff
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import Quox.ST
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import Data.IORef
export
localAt : (0 lbl : tag) -> Has (StateL lbl s) fs =>
(s -> s) -> Eff fs a -> Eff fs a
localAt lbl f act = do
old <- getAt lbl
modifyAt lbl f *> act <* putAt lbl old
export %inline
localAt_ : (0 lbl : tag) -> Has (StateL lbl s) fs =>
s -> Eff fs a -> Eff fs a
localAt_ lbl x = localAt lbl $ const x
export %inline
local : Has (State s) fs => (s -> s) -> Eff fs a -> Eff fs a
local = localAt ()
export %inline
local_ : Has (State s) fs => s -> Eff fs a -> Eff fs a
local_ = localAt_ ()
export %inline
getsAt : (0 lbl : tag) -> Has (StateL lbl s) fs => (s -> a) -> Eff fs a
getsAt lbl f = f <$> getAt lbl
export %inline
gets : Has (State s) fs => (s -> a) -> Eff fs a
gets = getsAt ()
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export
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handleStateIORef : HasIO m => IORef st -> StateL lbl st a -> m a
handleStateIORef r Get = readIORef r
handleStateIORef r (Put s) = writeIORef r s
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export
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handleStateSTRef : HasST m => STRef s st -> StateL lbl st a -> m s a
handleStateSTRef r Get = readRef r
handleStateSTRef r (Put s) = writeRef r s
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public export
data Length : List a -> Type where
Z : Length []
S : Length xs -> Length (x :: xs)
%builtin Natural Length
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export
subsetWith : Length xs => (forall z. Has z xs -> Has z ys) ->
Subset xs ys
subsetWith @{Z} f = []
subsetWith @{S len} f = f Z :: subsetWith (f . S)
export
subsetSelf : Length xs => Subset xs xs
subsetSelf = subsetWith id
export
subsetTail : Length xs => (0 x : a) -> Subset xs (x :: xs)
subsetTail _ = subsetWith S
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export
catchMaybeAt : (0 lbl : tag) -> (Has (ExceptL lbl e) fs, Length fs) =>
(e -> Eff fs a) -> Eff fs a -> Eff fs a
catchMaybeAt lbl hnd act =
catchAt lbl hnd $ lift @{subsetTail $ ExceptL lbl e} act
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export %inline
catchMaybe : (Has (Except e) fs, Length fs) =>
(e -> Eff fs a) -> Eff fs a -> Eff fs a
catchMaybe = catchMaybeAt ()
export
wrapErrAt : (0 lbl : tag) -> (Has (ExceptL lbl e) fs, Length fs) =>
(e -> e) -> Eff fs a -> Eff fs a
wrapErrAt lbl wrap = catchMaybeAt lbl (\ex => throwAt lbl $ wrap ex)
export %inline
wrapErr : (Has (Except e) fs, Length fs) => (e -> e) -> Eff fs a -> Eff fs a
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wrapErr = wrapErrAt ()
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export
handleExcept : Functor m => (forall c. e -> m c) -> ExceptL lbl e a -> m a
handleExcept thr (Err e) = thr e
export
handleReaderConst : Applicative m => r -> ReaderL lbl r a -> m a
handleReaderConst x Ask = pure x
public export
record IOErr e a where
constructor IOE
fromIOErr : IO (Either e a)
export
Functor (IOErr e) where
map f (IOE e) = IOE $ map f <$> e
export
Applicative (IOErr e) where
pure x = IOE $ pure $ pure x
IOE f <*> IOE x = IOE [|f <*> x|]
export
Monad (IOErr e) where
IOE m >>= k = IOE $ do
case !m of
Left err => pure $ Left err
Right x => fromIOErr $ k x
export
MonadRec (IOErr e) where
tailRecM s (Access r) x k = IOE $ do
let IOE m = k s x
case !m of
Left err => pure $ Left err
Right (Cont s' p y) => fromIOErr $ tailRecM s' (r s' p) y k
Right (Done y) => pure $ Right y
export
HasIO (IOErr e) where
liftIO = IOE . map Right
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export %inline
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ioLeft : e -> IOErr e a
ioLeft = IOE . pure . Left