Data.Extensible.Effect

Name-based extensible effects

Base

data Instruction xs a where

A unit of named effects.

Constructors

Instruction :: !(Membership xs kv) -> AssocValue kv a -> Instruction xs a

type Eff xs = Skeleton (Instruction xs)

The extensible operational monad

liftEff :: forall s t xs a. Associate s t xs => Proxy s -> t a -> Eff xs a

Lift an instruction onto an Eff action.

liftsEff :: forall s t xs a r. Associate s t xs => Proxy s -> t a -> (a -> r) -> Eff xs r

Lift an instruction onto an Eff action and apply a function to the result.

hoistEff :: forall s t xs a. Associate s t xs => Proxy s -> (forall x. t x -> t x) -> Eff xs a -> Eff xs a

Censor a specific type of effects in an action.

Step-wise handling

newtype Interpreter f g

Transformation between effects

Constructors

Interpreter

Fields

• runInterpreter :: forall a. g a -> f a

handleEff :: RecordOf (Interpreter m) xs -> Eff xs a -> MonadView m (Eff xs) a

Process an Eff action using a record of Interpreters.

Peeling

peelEff

Arguments

:: Rebinder xs r

Re-bind an unrelated action

-> (a -> r)

return the result

-> (forall x. t x -> (x -> r) -> r)

Handle the foremost type of an action

-> Eff ((k >: t) ': xs) a

-> r

Build a relay-style handler from a triple of functions.

runStateEff = peelEff rebindEff1 (a s -> return (a, s))
  (m k s -> let (a, s') = runState m s in k a s')

type Rebinder xs r = forall x. Instruction xs x -> (x -> r) -> r

A function to bind an Instruction in peelEff.

rebindEff0 :: Rebinder xs (Eff xs r)

A common value for the second argument of peelEff. Binds an instruction directly.

rebindEff1 :: Rebinder xs (a -> Eff xs r)

A pre-defined value for the second argument of peelEff. Preserves the argument of the continuation.

rebindEff2 :: Rebinder xs (a -> b -> Eff xs r)

A pre-defined value for the second argument of peelEff. Preserves two arguments of the continuation.

leaveEff :: Eff '[] a -> a

Reveal the final result of Eff.

retractEff :: forall k m a. Monad m => Eff '[k >: m] a -> m a

Tear down an action using the Monad instance of the instruction.

Anonymous actions

data Action args a r where

Anonymous representation of instructions.

Constructors

AResult :: Action '[] a a

AArgument :: x -> Action xs a r -> Action (x ': xs) a r

type family Function args r :: * where ...

Function [a, b, c] r is a -> b -> c -> r

Equations

Function '[] r = r

Function (x ': xs) r = x -> Function xs r

runAction :: Function xs (f a) -> Action xs a r -> f r

Pass the arguments of Action to the supplied function.

(@!?) :: FieldName k -> Function xs (f a) -> Field (Interpreter f) (k :> Action xs a) infix 1

Create a Field of a Interpreter for an Action.

peelAction

Arguments

:: (forall x. Instruction xs x -> (x -> r) -> r)

Re-bind an unrelated action

-> (a -> r)

return the result

-> Function ps ((q -> r) -> r)

Handle the foremost action

-> Eff ((k >: Action ps q) ': xs) a

-> r

Specialised version of peelEff for Actions. You can pass a function a -> b -> ... -> (q -> r) -> r as a handler for Action '[a, b, ...] q.

transformers-compatible actions and handlers

Reader

type ReaderEff = (:~:)

The reader monad is characterised by a type equality between the result type and the enviroment type.

askEff :: forall k r xs. Associate k (ReaderEff r) xs => Proxy k -> Eff xs r

Fetch the environment.

asksEff :: forall k r xs a. Associate k (ReaderEff r) xs => Proxy k -> (r -> a) -> Eff xs a

Pass the environment to a function.

localEff :: forall k r xs a. Associate k (ReaderEff r) xs => Proxy k -> (r -> r) -> Eff xs a -> Eff xs a

Modify the enviroment locally.

runReaderEff :: forall k r xs a. Eff ((k >: ReaderEff r) ': xs) a -> r -> Eff xs a

Run the frontal reader effect.

State

type State s = StateT s Identity

A state monad parameterized by the type s of the state to carry.

The return function leaves the state unchanged, while >>= uses the final state of the first computation as the initial state of the second.

getEff :: forall k s xs. Associate k (State s) xs => Proxy k -> Eff xs s

Get the current state.

getsEff :: forall k s a xs. Associate k (State s) xs => Proxy k -> (s -> a) -> Eff xs a

Pass the current state to a function.

putEff :: forall k s xs. Associate k (State s) xs => Proxy k -> s -> Eff xs ()

Replace the state with a new value.

modifyEff :: forall k s xs. Associate k (State s) xs => Proxy k -> (s -> s) -> Eff xs ()

Modify the state.

stateEff :: forall k s xs a. Associate k (State s) xs => Proxy k -> (s -> (a, s)) -> Eff xs a

Lift a state modification function.

runStateEff :: forall k s xs a. Eff ((k >: State s) ': xs) a -> s -> Eff xs (a, s)

Run the frontal state effect.

Writer

type WriterEff w = (,) w

(,) already is a writer monad.

writerEff :: forall k w xs a. Associate k (WriterEff w) xs => Proxy k -> (a, w) -> Eff xs a

Write the second element and return the first element.

tellEff :: forall k w xs. Associate k (WriterEff w) xs => Proxy k -> w -> Eff xs ()

Write a value.

listenEff :: forall k w xs a. (Associate k (WriterEff w) xs, Monoid w) => Proxy k -> Eff xs a -> Eff xs (a, w)

Squash the outputs into one step and return it.

passEff :: forall k w xs a. (Associate k (WriterEff w) xs, Monoid w) => Proxy k -> Eff xs (a, w -> w) -> Eff xs a

Modify the output using the function in the result.

runWriterEff :: forall k w xs a. Monoid w => Eff ((k >: WriterEff w) ': xs) a -> Eff xs (a, w)

Run the frontal writer effect.

Maybe

type MaybeEff = Const ()

An effect with no result

runMaybeEff :: forall k xs a. Eff ((k >: MaybeEff) ': xs) a -> Eff xs (Maybe a)

Run an effect which may fail in the name of k.

Either

type EitherEff = Const

Throwing an exception

throwEff :: Associate k (EitherEff e) xs => Proxy k -> e -> Eff xs a

Throw an exception e, throwing the rest of the computation away.

catchEff :: forall k e xs a. Associate k (EitherEff e) xs => Proxy k -> Eff xs a -> (e -> Eff xs a) -> Eff xs a

Attach a handler for an exception.

runEitherEff :: forall k e xs a. Eff ((k >: EitherEff e) ': xs) a -> Eff xs (Either e a)

Run the frontal Either effect.

Iter

data Identity a :: * -> *

Identity functor and monad. (a non-strict monad)

Since: 4.8.0.0

Instances

Monad Identity

Methods

(>>=) :: Identity a -> (a -> Identity b) -> Identity b

(>>) :: Identity a -> Identity b -> Identity b

return :: a -> Identity a

fail :: String -> Identity a

Functor Identity

Methods

fmap :: (a -> b) -> Identity a -> Identity b

(<$) :: a -> Identity b -> Identity a

MonadFix Identity

Methods

mfix :: (a -> Identity a) -> Identity a

Applicative Identity

Methods

pure :: a -> Identity a

(<*>) :: Identity (a -> b) -> Identity a -> Identity b

(*>) :: Identity a -> Identity b -> Identity b

(<*) :: Identity a -> Identity b -> Identity a

Foldable Identity

Methods

fold :: Monoid m => Identity m -> m

foldMap :: Monoid m => (a -> m) -> Identity a -> m

foldr :: (a -> b -> b) -> b -> Identity a -> b

foldr' :: (a -> b -> b) -> b -> Identity a -> b

foldl :: (b -> a -> b) -> b -> Identity a -> b

foldl' :: (b -> a -> b) -> b -> Identity a -> b

foldr1 :: (a -> a -> a) -> Identity a -> a

foldl1 :: (a -> a -> a) -> Identity a -> a

toList :: Identity a -> [a]

null :: Identity a -> Bool

length :: Identity a -> Int

elem :: Eq a => a -> Identity a -> Bool

maximum :: Ord a => Identity a -> a

minimum :: Ord a => Identity a -> a

sum :: Num a => Identity a -> a

product :: Num a => Identity a -> a

Traversable Identity

Methods

traverse :: Applicative f => (a -> f b) -> Identity a -> f (Identity b)

sequenceA :: Applicative f => Identity (f a) -> f (Identity a)

mapM :: Monad m => (a -> m b) -> Identity a -> m (Identity b)

sequence :: Monad m => Identity (m a) -> m (Identity a)

Generic1 Identity

Associated Types

type Rep1 (Identity :: * -> *) :: * -> *

Methods

from1 :: Identity a -> Rep1 Identity a

to1 :: Rep1 Identity a -> Identity a

Eq1 Identity

Methods

liftEq :: (a -> b -> Bool) -> Identity a -> Identity b -> Bool

Ord1 Identity

Methods

liftCompare :: (a -> b -> Ordering) -> Identity a -> Identity b -> Ordering

Read1 Identity

Methods

liftReadsPrec :: (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (Identity a)

liftReadList :: (Int -> ReadS a) -> ReadS [a] -> ReadS [Identity a]

Show1 Identity

Methods

liftShowsPrec :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> Identity a -> ShowS

liftShowList :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> [Identity a] -> ShowS

MonadZip Identity

Methods

mzip :: Identity a -> Identity b -> Identity (a, b)

mzipWith :: (a -> b -> c) -> Identity a -> Identity b -> Identity c

munzip :: Identity (a, b) -> (Identity a, Identity b)

Comonad Identity

Methods

extract :: Identity a -> a

duplicate :: Identity a -> Identity (Identity a)

extend :: (Identity a -> b) -> Identity a -> Identity b

ComonadApply Identity

Methods

(<@>) :: Identity (a -> b) -> Identity a -> Identity b

(@>) :: Identity a -> Identity b -> Identity b

(<@) :: Identity a -> Identity b -> Identity a

Sieve (->) Identity

Methods

sieve :: (a -> b) -> a -> Identity b

Cosieve (->) Identity

Methods

cosieve :: (a -> b) -> Identity a -> b

() :=> (Monad Identity)

Methods

ins :: () :- Monad Identity

() :=> (Functor Identity)

Methods

ins :: () :- Functor Identity

Bounded a => Bounded (Identity a)

Methods

minBound :: Identity a

maxBound :: Identity a

Enum a => Enum (Identity a)

Methods

succ :: Identity a -> Identity a

pred :: Identity a -> Identity a

toEnum :: Int -> Identity a

fromEnum :: Identity a -> Int

enumFrom :: Identity a -> [Identity a]

enumFromThen :: Identity a -> Identity a -> [Identity a]

enumFromTo :: Identity a -> Identity a -> [Identity a]

enumFromThenTo :: Identity a -> Identity a -> Identity a -> [Identity a]

Eq a => Eq (Identity a)

Methods

(==) :: Identity a -> Identity a -> Bool

(/=) :: Identity a -> Identity a -> Bool

Floating a => Floating (Identity a)

Methods

pi :: Identity a

exp :: Identity a -> Identity a

log :: Identity a -> Identity a

sqrt :: Identity a -> Identity a

(**) :: Identity a -> Identity a -> Identity a

logBase :: Identity a -> Identity a -> Identity a

sin :: Identity a -> Identity a

cos :: Identity a -> Identity a

tan :: Identity a -> Identity a

asin :: Identity a -> Identity a

acos :: Identity a -> Identity a

atan :: Identity a -> Identity a

sinh :: Identity a -> Identity a

cosh :: Identity a -> Identity a

tanh :: Identity a -> Identity a

asinh :: Identity a -> Identity a

acosh :: Identity a -> Identity a

atanh :: Identity a -> Identity a

log1p :: Identity a -> Identity a

expm1 :: Identity a -> Identity a

log1pexp :: Identity a -> Identity a

log1mexp :: Identity a -> Identity a

Fractional a => Fractional (Identity a)

Methods

(/) :: Identity a -> Identity a -> Identity a

recip :: Identity a -> Identity a

fromRational :: Rational -> Identity a

Integral a => Integral (Identity a)

Methods

quot :: Identity a -> Identity a -> Identity a

rem :: Identity a -> Identity a -> Identity a

div :: Identity a -> Identity a -> Identity a

mod :: Identity a -> Identity a -> Identity a

quotRem :: Identity a -> Identity a -> (Identity a, Identity a)

divMod :: Identity a -> Identity a -> (Identity a, Identity a)

toInteger :: Identity a -> Integer

Data a => Data (Identity a)

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Identity a -> c (Identity a)

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Identity a)

toConstr :: Identity a -> Constr

dataTypeOf :: Identity a -> DataType

dataCast1 :: Typeable (* -> *) t => (forall d. Data d => c (t d)) -> Maybe (c (Identity a))

dataCast2 :: Typeable (* -> * -> *) t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Identity a))

gmapT :: (forall b. Data b => b -> b) -> Identity a -> Identity a

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Identity a -> r

gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Identity a -> r

gmapQ :: (forall d. Data d => d -> u) -> Identity a -> [u]

gmapQi :: Int -> (forall d. Data d => d -> u) -> Identity a -> u

gmapM :: Monad m => (forall d. Data d => d -> m d) -> Identity a -> m (Identity a)

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Identity a -> m (Identity a)

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Identity a -> m (Identity a)

Num a => Num (Identity a)

Methods

(+) :: Identity a -> Identity a -> Identity a

(-) :: Identity a -> Identity a -> Identity a

(*) :: Identity a -> Identity a -> Identity a

negate :: Identity a -> Identity a

abs :: Identity a -> Identity a

signum :: Identity a -> Identity a

fromInteger :: Integer -> Identity a

Ord a => Ord (Identity a)

Methods

compare :: Identity a -> Identity a -> Ordering

(<) :: Identity a -> Identity a -> Bool

(<=) :: Identity a -> Identity a -> Bool

(>) :: Identity a -> Identity a -> Bool

(>=) :: Identity a -> Identity a -> Bool

max :: Identity a -> Identity a -> Identity a

min :: Identity a -> Identity a -> Identity a

Read a => Read (Identity a)

This instance would be equivalent to the derived instances of the Identity newtype if the runIdentity field were removed

Methods

readsPrec :: Int -> ReadS (Identity a)

readList :: ReadS [Identity a]

readPrec :: ReadPrec (Identity a)

readListPrec :: ReadPrec [Identity a]

Real a => Real (Identity a)

Methods

toRational :: Identity a -> Rational

RealFloat a => RealFloat (Identity a)

Methods

floatRadix :: Identity a -> Integer

floatDigits :: Identity a -> Int

floatRange :: Identity a -> (Int, Int)

decodeFloat :: Identity a -> (Integer, Int)

encodeFloat :: Integer -> Int -> Identity a

exponent :: Identity a -> Int

significand :: Identity a -> Identity a

scaleFloat :: Int -> Identity a -> Identity a

isNaN :: Identity a -> Bool

isInfinite :: Identity a -> Bool

isDenormalized :: Identity a -> Bool

isNegativeZero :: Identity a -> Bool

isIEEE :: Identity a -> Bool

atan2 :: Identity a -> Identity a -> Identity a

RealFrac a => RealFrac (Identity a)

Methods

properFraction :: Integral b => Identity a -> (b, Identity a)

truncate :: Integral b => Identity a -> b

round :: Integral b => Identity a -> b

ceiling :: Integral b => Identity a -> b

floor :: Integral b => Identity a -> b

Show a => Show (Identity a)

This instance would be equivalent to the derived instances of the Identity newtype if the runIdentity field were removed

Methods

showsPrec :: Int -> Identity a -> ShowS

show :: Identity a -> String

showList :: [Identity a] -> ShowS

Ix a => Ix (Identity a)

Methods

range :: (Identity a, Identity a) -> [Identity a]

index :: (Identity a, Identity a) -> Identity a -> Int

unsafeIndex :: (Identity a, Identity a) -> Identity a -> Int

inRange :: (Identity a, Identity a) -> Identity a -> Bool

rangeSize :: (Identity a, Identity a) -> Int

unsafeRangeSize :: (Identity a, Identity a) -> Int

IsString a => IsString (Identity a)

Methods

fromString :: String -> Identity a

Generic (Identity a)

Associated Types

type Rep (Identity a) :: * -> *

Methods

from :: Identity a -> Rep (Identity a) x

to :: Rep (Identity a) x -> Identity a

Semigroup a => Semigroup (Identity a)

Methods

(<>) :: Identity a -> Identity a -> Identity a

sconcat :: NonEmpty (Identity a) -> Identity a

stimes :: Integral b => b -> Identity a -> Identity a

Monoid a => Monoid (Identity a)

Methods

mempty :: Identity a

mappend :: Identity a -> Identity a -> Identity a

mconcat :: [Identity a] -> Identity a

Storable a => Storable (Identity a)

Methods

sizeOf :: Identity a -> Int

alignment :: Identity a -> Int

peekElemOff :: Ptr (Identity a) -> Int -> IO (Identity a)

pokeElemOff :: Ptr (Identity a) -> Int -> Identity a -> IO ()

peekByteOff :: Ptr b -> Int -> IO (Identity a)

pokeByteOff :: Ptr b -> Int -> Identity a -> IO ()

peek :: Ptr (Identity a) -> IO (Identity a)

poke :: Ptr (Identity a) -> Identity a -> IO ()

Bits a => Bits (Identity a)

Methods

(.&.) :: Identity a -> Identity a -> Identity a

(.|.) :: Identity a -> Identity a -> Identity a

xor :: Identity a -> Identity a -> Identity a

complement :: Identity a -> Identity a

shift :: Identity a -> Int -> Identity a

rotate :: Identity a -> Int -> Identity a

zeroBits :: Identity a

bit :: Int -> Identity a

setBit :: Identity a -> Int -> Identity a

clearBit :: Identity a -> Int -> Identity a

complementBit :: Identity a -> Int -> Identity a

testBit :: Identity a -> Int -> Bool

bitSizeMaybe :: Identity a -> Maybe Int

bitSize :: Identity a -> Int

isSigned :: Identity a -> Bool

shiftL :: Identity a -> Int -> Identity a

unsafeShiftL :: Identity a -> Int -> Identity a

shiftR :: Identity a -> Int -> Identity a

unsafeShiftR :: Identity a -> Int -> Identity a

rotateL :: Identity a -> Int -> Identity a

rotateR :: Identity a -> Int -> Identity a

popCount :: Identity a -> Int

FiniteBits a => FiniteBits (Identity a)

Methods

finiteBitSize :: Identity a -> Int

countLeadingZeros :: Identity a -> Int

countTrailingZeros :: Identity a -> Int

NFData a => NFData (Identity a)

Since: 1.4.0.0

Methods

rnf :: Identity a -> ()

Wrapper * Identity

Associated Types

type Repr Identity (h :: Identity -> *) (v :: Identity) :: *

Methods

_Wrapper :: (Functor f, Profunctor p) => Optic' * * p f (h v) (Repr Identity h v)

(Bounded a) :=> (Bounded (Identity a))

Methods

ins :: Bounded a :- Bounded (Identity a)

(Enum a) :=> (Enum (Identity a))

Methods

ins :: Enum a :- Enum (Identity a)

(Eq a) :=> (Eq (Identity a))

Methods

ins :: Eq a :- Eq (Identity a)

(Floating a) :=> (Floating (Identity a))

Methods

ins :: Floating a :- Floating (Identity a)

(Fractional a) :=> (Fractional (Identity a))

Methods

ins :: Fractional a :- Fractional (Identity a)

(Integral a) :=> (Integral (Identity a))

Methods

ins :: Integral a :- Integral (Identity a)

(Num a) :=> (Num (Identity a))

Methods

ins :: Num a :- Num (Identity a)

(Ord a) :=> (Ord (Identity a))

Methods

ins :: Ord a :- Ord (Identity a)

(Read a) :=> (Read (Identity a))

Methods

ins :: Read a :- Read (Identity a)

(Real a) :=> (Real (Identity a))

Methods

ins :: Real a :- Real (Identity a)

(RealFloat a) :=> (RealFloat (Identity a))

Methods

ins :: RealFloat a :- RealFloat (Identity a)

(RealFrac a) :=> (RealFrac (Identity a))

Methods

ins :: RealFrac a :- RealFrac (Identity a)

(Show a) :=> (Show (Identity a))

Methods

ins :: Show a :- Show (Identity a)

(Monoid a) :=> (Monoid (Identity a))

Methods

ins :: Monoid a :- Monoid (Identity a)

(Bits a) :=> (Bits (Identity a))

Methods

ins :: Bits a :- Bits (Identity a)

type Rep1 Identity

type Rep1 Identity = D1 (MetaData "Identity" "Data.Functor.Identity" "base" True) (C1 (MetaCons "Identity" PrefixI True) (S1 (MetaSel (Just Symbol "runIdentity") NoSourceUnpackedness NoSourceStrictness DecidedLazy) Par1))

type Rep (Identity a)

type Rep (Identity a) = D1 (MetaData "Identity" "Data.Functor.Identity" "base" True) (C1 (MetaCons "Identity" PrefixI True) (S1 (MetaSel (Just Symbol "runIdentity") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 a)))

type Repr * Identity a

type Repr * Identity a = a

tickEff :: Associate k Identity xs => Proxy k -> Eff xs ()

Put a milestone on a computation.

runIterEff :: Eff ((k >: Identity) ': xs) a -> Eff xs (Either a (Eff ((k >: Identity) ': xs) a))

Run a computation until tickEff.