Control.Effect.Reader

Documentation

data Reader s a

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

Constructors

IxR

Fields

runReader :: Set s -> a

Instances

Effect [*] Reader

Subset s t => Subeffect [*] Reader s t

If s is a subset of t then, s is a subeffect of t

type Unit [*] Reader = [] *

type Plus [*] Reader f g = Union f g

type Inv [*] Reader f g = (IsSet f, IsSet g, Split f g (Union f g))

ask :: Var v -> Reader `[v :-> a]` a

ask for a variable v of type a, raising an effect

merge :: Unionable s t => (a -> Reader (Union s t) b) -> Reader s (a -> Reader t b)

Provides a way to emulated the ImplicitParams features of GHC/Haskell

data k :-> v infixl 2

Constructors

(Var k) :-> v infixl 2

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)

data Var k where

Constructors

Var :: Var k

X :: Var "x"

Y :: Var "y"

Z :: Var "z"

Instances

Show (Var "x")

Show (Var "y")

Show (Var "z")

class Subset s t

Minimal complete definition

subset

Instances

Subset s t => Subset s ((:) * x t)

Subset ([] *) t

Subset s t => Subset ((:) * x s) ((:) * x t)

data Set n where

Constructors

Empty :: Set []

Ext :: e -> Set s -> Set (e : s)

Instances

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

Show (Set ([] *))