Moo.Prelude

Invocation helpers for functions with effects in a monad D and which are stored in the environment E of a reader-like monad M.

Documentation

self :: Call curried => (E -> curried) -> LiftedD curried

Given a way of extracting from the environment E a curried function that ends in a D action, lift the curried D-function into the main monad M.

call :: forall component curried. (Has component D E, Call curried) => (component D -> curried) -> LiftedD curried

Provided that the environment E Has a component, and given a way of extracting from the component a curried function that ends in a D action, lift the curried D-function into the main monad M.

The extractor must be monomorphic on the component, so that the intended instance of Has is picked.

The typical case is for the component to be a parameterized record and for the extractor to be a field accessor.

Re-exports from Moo

data M :: Type -> Type

A reader-like monad.

Instances

Monad M

Defined in Moo

Methods

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

(>>) :: M a -> M b -> M b

return :: a -> M a

Functor M

Defined in Moo

Methods

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

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

Applicative M

Defined in Moo

Methods

pure :: a -> M a

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

liftA2 :: (a -> b -> c) -> M a -> M b -> M c

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

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

MonadReader E M

Defined in Moo

Methods

ask :: M E

local :: (E -> E) -> M a -> M a

reader :: (E -> a) -> M a

data E :: Type

The monad environment.

Instances

MonadReader E M

Defined in Moo

Methods

ask :: M E

local :: (E -> E) -> M a -> M a

reader :: (E -> a) -> M a

data D :: Type -> Type

The monad in which the functions in the environment have their effects.

We don't require Functor, Applicative or Monad from D because the plan is to always lift D values to M as soon as they're obtained.