Copyright	(c) 2023-2025 Sayo contributors
License	MPL-2.0 (see the file LICENSE)
Maintainer	ymdfield@outlook.jp
Safe Haskell	None
Language	GHC2021

Data.Effect.Writer

Description

Effects that can accumulate values monoidally in a context.

Synopsis

tell :: forall w a (es :: [Effect]) (ff :: (Type -> Type) -> Type -> Type) (c :: (Type -> Type) -> Constraint). (Free c ff, a ~ Eff ff es, Tell w :> es) => w -> a ()
listen :: forall a1 w a (es :: [Effect]) (ff :: (Type -> Type) -> Type -> Type) (c :: (Type -> Type) -> Constraint). (Free c ff, a ~ Eff ff es, WriterH w :> es) => a a1 -> a (w, a1)
censor :: forall w b a (es :: [Effect]) (ff :: (Type -> Type) -> Type -> Type) (c :: (Type -> Type) -> Constraint). (Free c ff, a ~ Eff ff es, WriterH w :> es) => (w -> w) -> a b -> a b
censorPre :: forall w (es :: [Effect]) (ff :: (Type -> Type) -> Type -> Type) a (c :: (Type -> Type) -> Constraint). (In (Tell w) es, Free c ff) => (w -> w) -> Eff ff es a -> Eff ff es a
tell'_ :: forall w a (es :: [Effect]) (ff :: (Type -> Type) -> Type -> Type) (c :: (Type -> Type) -> Constraint). (Free c ff, a ~ Eff ff es, In (Tell w) es) => w -> a ()
tell' :: forall {k} (key :: k) w a (es :: [Effect]) (ff :: (Type -> Type) -> Type -> Type) (c :: (Type -> Type) -> Constraint). (Free c ff, a ~ Eff ff es, Has key (Tell w) es) => w -> a ()
tell'' :: forall {k} (tag :: k) w a (es :: [Effect]) (ff :: (Type -> Type) -> Type -> Type) (c :: (Type -> Type) -> Constraint). (Free c ff, a ~ Eff ff es, Tagged tag (Tell w) :> es) => w -> a ()
listen' :: forall {k} (key :: k) a1 w a (es :: [Effect]) (ff :: (Type -> Type) -> Type -> Type) (c :: (Type -> Type) -> Constraint). (Free c ff, a ~ Eff ff es, Has key (WriterH w) es) => a a1 -> a (w, a1)
listen'' :: forall {k} (tag :: k) a1 w a (es :: [Effect]) (ff :: (Type -> Type) -> Type -> Type) (c :: (Type -> Type) -> Constraint). (Free c ff, a ~ Eff ff es, Tagged tag (WriterH w) :> es) => a a1 -> a (w, a1)
listen'_ :: forall a1 w a (es :: [Effect]) (ff :: (Type -> Type) -> Type -> Type) (c :: (Type -> Type) -> Constraint). (Free c ff, a ~ Eff ff es, In (WriterH w) es) => a a1 -> a (w, a1)
censor' :: forall {k} (key :: k) w b a (es :: [Effect]) (ff :: (Type -> Type) -> Type -> Type) (c :: (Type -> Type) -> Constraint). (Free c ff, a ~ Eff ff es, Has key (WriterH w) es) => (w -> w) -> a b -> a b
censor'' :: forall {k} (tag :: k) w b a (es :: [Effect]) (ff :: (Type -> Type) -> Type -> Type) (c :: (Type -> Type) -> Constraint). (Free c ff, a ~ Eff ff es, Tagged tag (WriterH w) :> es) => (w -> w) -> a b -> a b
censor'_ :: forall w b a (es :: [Effect]) (ff :: (Type -> Type) -> Type -> Type) (c :: (Type -> Type) -> Constraint). (Free c ff, a ~ Eff ff es, In (WriterH w) es) => (w -> w) -> a b -> a b
data Tell w (a :: Type -> Type) b where
- Tell :: forall w (a :: Type -> Type). w -> Tell w a ()
data WriterH w (a :: Type -> Type) b where
- Listen :: forall (a :: Type -> Type) a1 w. a a1 -> WriterH w a (w, a1)
- Censor :: forall w (a :: Type -> Type) b. (w -> w) -> a b -> WriterH w a b
pass :: forall w a (es :: [Effect]) (ff :: (Type -> Type) -> Type -> Type) (c :: (Type -> Type) -> Constraint). (Tell w :> es, WriterH w :> es, Monad (Eff ff es), Free c ff) => Eff ff es (w -> w, a) -> Eff ff es a

Documentation

tell :: forall w a (es :: [Effect]) (ff :: (Type -> Type) -> Type -> Type) (c :: (Type -> Type) -> Constraint). (Free c ff, a ~ Eff ff es, Tell w :> es) => w -> a () Source #

listen :: forall a1 w a (es :: [Effect]) (ff :: (Type -> Type) -> Type -> Type) (c :: (Type -> Type) -> Constraint). (Free c ff, a ~ Eff ff es, WriterH w :> es) => a a1 -> a (w, a1) Source #

censor :: forall w b a (es :: [Effect]) (ff :: (Type -> Type) -> Type -> Type) (c :: (Type -> Type) -> Constraint). (Free c ff, a ~ Eff ff es, WriterH w :> es) => (w -> w) -> a b -> a b Source #

censorPre :: forall w (es :: [Effect]) (ff :: (Type -> Type) -> Type -> Type) a (c :: (Type -> Type) -> Constraint). (In (Tell w) es, Free c ff) => (w -> w) -> Eff ff es a -> Eff ff es a Source #

censor with pre-applying semantics.

tell'_ :: forall w a (es :: [Effect]) (ff :: (Type -> Type) -> Type -> Type) (c :: (Type -> Type) -> Constraint). (Free c ff, a ~ Eff ff es, In (Tell w) es) => w -> a () Source #

tell' :: forall {k} (key :: k) w a (es :: [Effect]) (ff :: (Type -> Type) -> Type -> Type) (c :: (Type -> Type) -> Constraint). (Free c ff, a ~ Eff ff es, Has key (Tell w) es) => w -> a () Source #

tell'' :: forall {k} (tag :: k) w a (es :: [Effect]) (ff :: (Type -> Type) -> Type -> Type) (c :: (Type -> Type) -> Constraint). (Free c ff, a ~ Eff ff es, Tagged tag (Tell w) :> es) => w -> a () Source #

listen' :: forall {k} (key :: k) a1 w a (es :: [Effect]) (ff :: (Type -> Type) -> Type -> Type) (c :: (Type -> Type) -> Constraint). (Free c ff, a ~ Eff ff es, Has key (WriterH w) es) => a a1 -> a (w, a1) Source #

listen'' :: forall {k} (tag :: k) a1 w a (es :: [Effect]) (ff :: (Type -> Type) -> Type -> Type) (c :: (Type -> Type) -> Constraint). (Free c ff, a ~ Eff ff es, Tagged tag (WriterH w) :> es) => a a1 -> a (w, a1) Source #

listen'_ :: forall a1 w a (es :: [Effect]) (ff :: (Type -> Type) -> Type -> Type) (c :: (Type -> Type) -> Constraint). (Free c ff, a ~ Eff ff es, In (WriterH w) es) => a a1 -> a (w, a1) Source #

censor' :: forall {k} (key :: k) w b a (es :: [Effect]) (ff :: (Type -> Type) -> Type -> Type) (c :: (Type -> Type) -> Constraint). (Free c ff, a ~ Eff ff es, Has key (WriterH w) es) => (w -> w) -> a b -> a b Source #

censor'' :: forall {k} (tag :: k) w b a (es :: [Effect]) (ff :: (Type -> Type) -> Type -> Type) (c :: (Type -> Type) -> Constraint). (Free c ff, a ~ Eff ff es, Tagged tag (WriterH w) :> es) => (w -> w) -> a b -> a b Source #

censor'_ :: forall w b a (es :: [Effect]) (ff :: (Type -> Type) -> Type -> Type) (c :: (Type -> Type) -> Constraint). (Free c ff, a ~ Eff ff es, In (WriterH w) es) => (w -> w) -> a b -> a b Source #

data Tell w (a :: Type -> Type) b where #

An effect that can accumulate values monoidally in a context.

Constructors

Tell :: forall w (a :: Type -> Type). w -> Tell w a ()

Accumulates new values to the cumulative value held in the context.

Instances

Instances details

FirstOrder (Tell w)
Instance details Defined in Data.Effect
PolyHFunctor (Tell w)
Instance details Defined in Data.Effect
HFunctor (Tell w)
Instance details Defined in Data.Effect Methods hfmap :: (forall x. f x -> g x) -> Tell w f a -> Tell w g a #
type FormOf (Tell w)
Instance details Defined in Data.Effect type FormOf (Tell w) = 'Polynomial
type LabelOf (Tell w)
Instance details Defined in Data.Effect type LabelOf (Tell w) = TellLabel
type OrderOf (Tell w)
Instance details Defined in Data.Effect type OrderOf (Tell w) = 'FirstOrder

data WriterH w (a :: Type -> Type) b where #

An effect that performs local operations on accumulations in the context on a per-scope basis.

Constructors

Listen	Obtains the accumulated value in the scope and returns it together as a pair.
Fields :: forall (a :: Type -> Type) a1 w. a a1 The scope from which to obtain the accumulation. -> WriterH w a (w, a1)
Censor	Modifies the accumulation in the scope based on the given function.
Fields :: forall w (a :: Type -> Type) b. (w -> w) A function for modifying the accumulated value. -> a b The scope where the modification is applied. -> WriterH w a b

Instances

Instances details

PolyHFunctor (WriterH w)
Instance details Defined in Data.Effect
HFunctor (WriterH w)
Instance details Defined in Data.Effect Methods hfmap :: (forall x. f x -> g x) -> WriterH w f a -> WriterH w g a #
type FormOf (WriterH w)
Instance details Defined in Data.Effect type FormOf (WriterH w) = 'Polynomial
type LabelOf (WriterH w)
Instance details Defined in Data.Effect type LabelOf (WriterH w) = WriterHLabel
type OrderOf (WriterH w)
Instance details Defined in Data.Effect type OrderOf (WriterH w) = 'HigherOrder

pass :: forall w a (es :: [Effect]) (ff :: (Type -> Type) -> Type -> Type) (c :: (Type -> Type) -> Constraint). (Tell w :> es, WriterH w :> es, Monad (Eff ff es), Free c ff) => Eff ff es (w -> w, a) -> Eff ff es a #

For a given scope, uses the function (the first component of the pair returned by that scope) to modify the accumulated value of that scope, and then accumulates the result into the current outer scope.

pass m = do
    (w, (f, a)) <- listen m
    tell $ f w
    pure a