Safe Haskell	Safe
Language	Haskell2010

Data.GADT.Show

Contents

Showing
Reading

Synopsis

class GShow t where
- gshowsPrec :: Int -> t a -> ShowS
defaultGshowsPrec :: Show (t a) => Int -> t a -> ShowS
gshows :: GShow t => t a -> ShowS
gshow :: GShow t => t a -> String
class GRead t where
- greadsPrec :: Int -> GReadS t
type GReadS t = String -> [(Some t, String)]
greads :: GRead t => GReadS t
gread :: GRead t => String -> (forall a. t a -> b) -> b
greadMaybe :: GRead t => String -> (forall a. t a -> b) -> Maybe b
getGReadResult :: Some tag -> (forall a. tag a -> b) -> b
mkGReadResult :: tag a -> Some tag

Showing

class GShow t where Source #

Show-like class for 1-type-parameter GADTs. GShow t => ... is equivalent to something like (forall a. Show (t a)) => .... The easiest way to create instances would probably be to write (or derive) an instance Show (T a), and then simply say:

instance GShow t where gshowsPrec = defaultGshowsPrec

Methods

gshowsPrec :: Int -> t a -> ShowS Source #

Instances

Instances details

GShow (TypeRep :: k -> Type) Source #
Instance details Defined in Data.GADT.Internal Methods gshowsPrec :: forall (a :: k0). Int -> TypeRep a -> ShowS Source #
GShow ((:~:) a :: k -> Type) Source #
Instance details Defined in Data.GADT.Internal Methods gshowsPrec :: forall (a0 :: k0). Int -> (a :~: a0) -> ShowS Source #
GShow (GOrdering a :: k -> Type) Source #
Instance details Defined in Data.GADT.Internal Methods gshowsPrec :: forall (a0 :: k0). Int -> GOrdering a a0 -> ShowS Source #
(GShow a, GShow b) => GShow (Product a b :: k -> Type) Source #	`>>>` `gshow (Pair Refl Refl :: Product ((:~:) Int) ((:~:) Int) Int)`"Pair Refl Refl"
Instance details Defined in Data.GADT.Internal Methods gshowsPrec :: forall (a0 :: k0). Int -> Product a b a0 -> ShowS Source #
(GShow a, GShow b) => GShow (Sum a b :: k -> Type) Source #	`>>>` `gshow (InL Refl :: Sum ((:~:) Int) ((:~:) Bool) Int)`"InL Refl"
Instance details Defined in Data.GADT.Internal Methods gshowsPrec :: forall (a0 :: k0). Int -> Sum a b a0 -> ShowS Source #
GShow ((:~~:) a :: k -> Type) Source #	Since: 1.0.4
Instance details Defined in Data.GADT.Internal Methods gshowsPrec :: forall (a0 :: k0). Int -> (a :~~: a0) -> ShowS Source #
(GShow a, GShow b) => GShow (a :*: b :: k -> Type) Source #	`>>>` `gshow (Pair Refl Refl :: Product ((:~:) Int) ((:~:) Int) Int)`"Refl :: Refl" Since: 1.0.4*
Instance details Defined in Data.GADT.Internal Methods gshowsPrec :: forall (a0 :: k0). Int -> (a :*: b) a0 -> ShowS Source #
(GShow a, GShow b) => GShow (a :+: b :: k -> Type) Source #	`>>>` `gshow (L1 Refl :: ((:~:) Int :+: (:~:) Bool) Int)`"L1 Refl" Since: 1.0.4
Instance details Defined in Data.GADT.Internal Methods gshowsPrec :: forall (a0 :: k0). Int -> (a :+: b) a0 -> ShowS Source #

defaultGshowsPrec :: Show (t a) => Int -> t a -> ShowS Source #

If f has a 'Show (f a)' instance, this function makes a suitable default implementation of gshowsPrec.

Since: 1.0.4

gshows :: GShow t => t a -> ShowS Source #

gshow :: GShow t => t a -> String Source #

Reading

class GRead t where Source #

Read-like class for 1-type-parameter GADTs. Unlike GShow, this one cannot be mechanically derived from a Read instance because greadsPrec must choose the phantom type based on the String being parsed.

Methods

greadsPrec :: Int -> GReadS t Source #

Instances

Instances details

GRead ((:~:) a :: k -> Type) Source #
Instance details Defined in Data.GADT.Internal Methods greadsPrec :: Int -> GReadS ((:~:) a) Source #
GRead (GOrdering a :: k -> Type) Source #
Instance details Defined in Data.GADT.Internal Methods greadsPrec :: Int -> GReadS (GOrdering a) Source #
(GRead a, GRead b) => GRead (Sum a b :: k -> Type) Source #
Instance details Defined in Data.GADT.Internal Methods greadsPrec :: Int -> GReadS (Sum a b) Source #
(GRead a, GRead b) => GRead (a :+: b :: k -> Type) Source #	Since: 1.0.4
Instance details Defined in Data.GADT.Internal Methods greadsPrec :: Int -> GReadS (a :+: b) Source #
k1 ~ k2 => GRead ((:~~:) a :: k2 -> Type) Source #	Since: 1.0.4
Instance details Defined in Data.GADT.Internal Methods greadsPrec :: Int -> GReadS ((:~~:) a) Source #

type GReadS t = String -> [(Some t, String)] Source #

GReadS t is equivalent to ReadS (forall b. (forall a. t a -> b) -> b), which is in turn equivalent to ReadS (Exists t) (with data Exists t where Exists :: t a -> Exists t)

greads :: GRead t => GReadS t Source #

gread :: GRead t => String -> (forall a. t a -> b) -> b Source #

greadMaybe :: GRead t => String -> (forall a. t a -> b) -> Maybe b Source #

>>> greadMaybe "InL Refl" mkSome :: Maybe (Some (Sum ((:~:) Int) ((:~:) Bool)))
Just (mkSome (InL Refl))

>>> greadMaybe "L1 Refl" mkSome :: Maybe (Some ((:~:) Int :+: (:~:) Bool))
Just (mkSome (L1 Refl))

>>> greadMaybe "garbage" mkSome :: Maybe (Some ((:~:) Int))
Nothing

getGReadResult :: Some tag -> (forall a. tag a -> b) -> b Source #

mkGReadResult :: tag a -> Some tag Source #