Safe Haskell	None
Language	GHC2021

Vary.VEither

Contents

General Usage
Core type definition
Conversion
case analysis ("pattern matching"):
Transforming

Synopsis

data VEither (errs :: [Type]) a where
- pattern VLeft :: forall a errs. Vary errs -> VEither errs a
- pattern VRight :: forall a errs. a -> VEither errs a
toVary :: VEither errs a -> Vary (a : errs)
fromVary :: Vary (a : errs) -> VEither errs a
fromLeft :: forall err errs a. err :| errs => err -> VEither errs a
fromRight :: forall a errs. a -> VEither errs a
toEither :: VEither errs a -> Either (Vary errs) a
fromEither :: Either (Vary errs) a -> VEither errs a
veither :: (Vary errs -> c) -> (a -> c) -> VEither errs a -> c
intoOnly :: forall a. VEither '[] a -> a
onLeft :: forall err b errs a. (err -> b) -> (VEither errs a -> b) -> VEither (err : errs) a -> b
onRight :: (a -> b) -> (VEither errs a -> b) -> VEither errs a -> b
mapLeftOn :: forall x y xs ys a. Mappable x y xs ys => (x -> y) -> VEither xs a -> VEither ys a
mapLeft :: (Vary xs -> Vary ys) -> VEither xs a -> VEither ys a
mapRight :: (x -> y) -> VEither errs x -> VEither errs y
morph :: forall ys xs a. Subset (a : xs) (a : ys) => VEither xs a -> VEither ys a
morphed :: forall xs ys a res. Subset (a : xs) (a : ys) => (VEither ys a -> res) -> VEither xs a -> res

General Usage

This module is intended to be used qualified:

>>> import Vary.VEither (VEither(VLeft, VRight))
>>> import qualified Vary.VEither as VEither

And for many functions, it is useful or outright necessary to enable the following extensions:

>>> :set -XGHC2021
>>> :set -XDataKinds

Core type definition

data VEither (errs :: [Type]) a where Source #

Bundled Patterns

pattern VLeft :: forall a errs. Vary errs -> VEither errs a
pattern VRight :: forall a errs. a -> VEither errs a

Instances

Instances details

Foldable (VEither errs) Source #
Instance details Defined in Vary.VEither Methods fold :: Monoid m => VEither errs m -> m # foldMap :: Monoid m => (a -> m) -> VEither errs a -> m # foldMap' :: Monoid m => (a -> m) -> VEither errs a -> m # foldr :: (a -> b -> b) -> b -> VEither errs a -> b # foldr' :: (a -> b -> b) -> b -> VEither errs a -> b # foldl :: (b -> a -> b) -> b -> VEither errs a -> b # foldl' :: (b -> a -> b) -> b -> VEither errs a -> b # foldr1 :: (a -> a -> a) -> VEither errs a -> a # foldl1 :: (a -> a -> a) -> VEither errs a -> a # toList :: VEither errs a -> [a] # null :: VEither errs a -> Bool # length :: VEither errs a -> Int # elem :: Eq a => a -> VEither errs a -> Bool # maximum :: Ord a => VEither errs a -> a # minimum :: Ord a => VEither errs a -> a # sum :: Num a => VEither errs a -> a # product :: Num a => VEither errs a -> a #
Traversable (VEither errs) Source #
Instance details Defined in Vary.VEither Methods traverse :: Applicative f => (a -> f b) -> VEither errs a -> f (VEither errs b) # sequenceA :: Applicative f => VEither errs (f a) -> f (VEither errs a) # mapM :: Monad m => (a -> m b) -> VEither errs a -> m (VEither errs b) # sequence :: Monad m => VEither errs (m a) -> m (VEither errs a) #
Applicative (VEither errs) Source #
Instance details Defined in Vary.VEither Methods pure :: a -> VEither errs a # (<>) :: VEither errs (a -> b) -> VEither errs a -> VEither errs b # liftA2 :: (a -> b -> c) -> VEither errs a -> VEither errs b -> VEither errs c # (>) :: VEither errs a -> VEither errs b -> VEither errs b # (<*) :: VEither errs a -> VEither errs b -> VEither errs a #
Functor (VEither errs) Source #
Instance details Defined in Vary.VEither Methods fmap :: (a -> b) -> VEither errs a -> VEither errs b # (<$) :: a -> VEither errs b -> VEither errs a #
Monad (VEither errs) Source #
Instance details Defined in Vary.VEither Methods (>>=) :: VEither errs a -> (a -> VEither errs b) -> VEither errs b # (>>) :: VEither errs a -> VEither errs b -> VEither errs b # return :: a -> VEither errs a #
Semigroup (VEither errs a) Source #
Instance details Defined in Vary.VEither Methods (<>) :: VEither errs a -> VEither errs a -> VEither errs a # sconcat :: NonEmpty (VEither errs a) -> VEither errs a # stimes :: Integral b => b -> VEither errs a -> VEither errs a #
Generic (VEither errs a) Source #
Instance details Defined in Vary.VEither Associated Types type Rep (VEither errs a) :: Type -> Type # Methods from :: VEither errs a -> Rep (VEither errs a) x # to :: Rep (VEither errs a) x -> VEither errs a #
(Show a, Show (Vary errs)) => Show (VEither errs a) Source #
Instance details Defined in Vary.VEither Methods showsPrec :: Int -> VEither errs a -> ShowS # show :: VEither errs a -> String # showList :: [VEither errs a] -> ShowS #
(NFData a, NFData (Vary errs)) => NFData (VEither errs a) Source #
Instance details Defined in Vary.VEither Methods rnf :: VEither errs a -> () #
(Eq a, Eq (Vary errs)) => Eq (VEither errs a) Source #
Instance details Defined in Vary.VEither Methods (==) :: VEither errs a -> VEither errs a -> Bool # (/=) :: VEither errs a -> VEither errs a -> Bool #
(Ord a, Ord (Vary errs)) => Ord (VEither errs a) Source #
Instance details Defined in Vary.VEither Methods compare :: VEither errs a -> VEither errs a -> Ordering # (<) :: VEither errs a -> VEither errs a -> Bool # (<=) :: VEither errs a -> VEither errs a -> Bool # (>) :: VEither errs a -> VEither errs a -> Bool # (>=) :: VEither errs a -> VEither errs a -> Bool # max :: VEither errs a -> VEither errs a -> VEither errs a # min :: VEither errs a -> VEither errs a -> VEither errs a #
type Rep (VEither errs a) Source #
Instance details Defined in Vary.VEither type Rep (VEither errs a) = D1 ('MetaData "VEither" "Vary.VEither" "vary" 'False) (C1 ('MetaCons "VLeft" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 (Vary errs))) :+: C1 ('MetaCons "VRight" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 a)))

Conversion

toVary :: VEither errs a -> Vary (a : errs) Source #

Turns the VEither into a normal Vary, no longer considering the a a 'preferred' value.

fromVary :: Vary (a : errs) -> VEither errs a Source #

Turns a Vary into a VEither. Now the a is considered the 'preferred' value.

fromLeft :: forall err errs a. err :| errs => err -> VEither errs a Source #

Shorthand to construct a VEither from a single error value.

Instead of:

>>> (VLeft (Vary.from @Bool True)) :: VEither '[Bool] String
VLeft (Vary.from @Bool True)

You can just write:

>>> VEither.fromLeft @Bool True :: VEither '[Bool] String
VLeft (Vary.from @Bool True)

fromRight :: forall a errs. a -> VEither errs a Source #

Construct a VEither from an a.

Exists for symmetry with fromLeft. Indeed, this is just another name for VRight.

toEither :: VEither errs a -> Either (Vary errs) a Source #

Turns a VEither into a normal Either.

fromEither :: Either (Vary errs) a -> VEither errs a Source #

Turns a normal Either into a VEither.

veither :: (Vary errs -> c) -> (a -> c) -> VEither errs a -> c Source #

Case analysis on a VEither. Similar to either.

See also VEither.mapLeft, VEither.mapLeftOn and VEither.mapRight.

intoOnly :: forall a. VEither '[] a -> a Source #

If you have a VEither which does not actually contain any errors, you can be sure it always contains an a.

Similar to Vary.intoOnly.

case analysis ("pattern matching"):

Besides the VLeft and VRight patterns, VEither supports a bunch of handy combinator functions, similar to Vary.on and co.

onLeft :: forall err b errs a. (err -> b) -> (VEither errs a -> b) -> VEither (err : errs) a -> b Source #

onRight :: (a -> b) -> (VEither errs a -> b) -> VEither errs a -> b Source #

Transforming

mapLeftOn :: forall x y xs ys a. Mappable x y xs ys => (x -> y) -> VEither xs a -> VEither ys a Source #

Map a function over one of the error values inside the VEither.

Any other VLeft and also VRight are kept untouched.

Similar to Vary.mapOn.

mapLeft :: (Vary xs -> Vary ys) -> VEither xs a -> VEither ys a Source #

Map a function over the VEither if it contains a VLeft, otherwise leave it alone.

See also VEither.mapLeftOn, VEither.mapRight and VEither.veither.

mapRight :: (x -> y) -> VEither errs x -> VEither errs y Source #

Map a function over the VEither if it contains a VRight, otherwise leave it alone.

Exists for symmetry with VEither.mapLeft and VEither.mapLeftOn.

Indeed, it is just another name for fmap.