Safe Haskell	None
Language	Haskell98

Control.Effect.Writer

Synopsis

Documentation

Provides an effect-parameterised version of the writer monad. Effects are sets of variable-type pairs, providing an effect system for writer effects.

Constructors

Writer
Fields runWriter :: (a, Set w)

Instances

Effect [*] Writer
Superset s t => Subeffect [*] Writer s t
type Unit [] Writer = []
type Plus [*] Writer s t = Union s t
type Inv [*] Writer s t = (IsSet s, IsSet t, Unionable s t)

data Symbol :: *

(Kind) This is the kind of type-level symbols.

Instances

type (==) Symbol a b = EqSymbol a b

put :: Var v -> a -> Writer `[v :-> a]` () Source

Write to variable v with value of type a

data k :-> v infixl 2 Source

Instances

(Show (Var k), Show v) => Show ((:->) k v)
Chooser (CmpSymbol j k) => OrdH ((:->) j u) ((:->) k v)
(Monoid u, Nubable ((:) * ((:->) k u) s)) => Nubable ((:) * ((:->) k u) ((:) * ((:->) k u) s))	Define the operation for removing duplicates using mappend
Update ((:) * ((:->) j ((:!) b s)) as) as' => Update ((:) * ((:->) k ((:!) a W)) ((:) * ((:->) j ((:!) b s)) as)) as'
Update ((:) * ((:->) k ((:!) a R)) as) as' => Update ((:) * ((:->) k ((:!) a W)) ((:) * ((:->) k ((:!) b R)) as)) as'
Update ((:) * ((:->) k ((:!) b R)) as) as' => Update ((:) * ((:->) k ((:!) a s)) ((:) * ((:->) k ((:!) b s)) as)) as'
Update ((:) * ((:->) j ((:!) b s)) as) as' => Update ((:) * ((:->) k ((:!) a R)) ((:) * ((:->) j ((:!) b s)) as)) ((:) * ((:->) k ((:!) a R)) as')
type Max ((:->) j u) ((:->) k v) = (:->) (Select Symbol j k k j) (Select * j k v u)
type Min ((:->) j u) ((:->) k v) = (:->) (Select Symbol j k j k) (Select * j k u v)

type IsSet s = s ~ Nub (Sort s) Source

data Set n where Source

Constructors

Empty :: Set []
Ext :: e -> Set s -> Set (e : s)

Instances

(Show e, Show' (Set s)) => Show (Set ((:) * e s))
Show (Set ([] *))

data Var k where Source

Constructors

Instances