TextShow.Generic

Generic versions of TextShow and TextShow1 class functions, as an alternative to TextShow.TH, which uses Template Haskell. Because there is no Generic2 class, TextShow2 cannot be implemented generically.

This implementation is loosely based off of the Generics.Deriving.Show module from the generic-deriving library.

Since: 2

Generic show functions

TextShow instances can be easily defined for data types that are Generic instances. The easiest way to do this is to use the DeriveGeneric extension.

{-# LANGUAGE DeriveGeneric #-}
import GHC.Generics
import TextShow
import TextShow.Generic

data D a = D a
  deriving (Generic, Generic1)

instance TextShow a => TextShow (D a) where
    showbPrec = genericShowbPrec

instance TextShow1 D where
    liftShowbPrec = genericLiftShowbPrec

Understanding a compiler error

Suppose you intend to use genericShowbPrec to define a TextShow instance.

data Oops = Oops
    -- forgot to add "deriving Generic" here!

instance TextShow Oops where
    showbPrec = genericShowbPrec

If you forget to add a deriving Generic clause to your data type, at compile-time, you might get an error message that begins roughly as follows:

No instance for (GTextShow Zero (Rep Oops))

This error can be confusing, but don't let it intimidate you. The correct fix is simply to add the missing "deriving Generic" clause.

Similarly, if the compiler complains about not having an instance for (GTextShow One (Rep1 Oops1)), add a "deriving Generic1" clause.

genericShowt :: (Generic a, GTextShow Zero (Rep a)) => a -> Text

A Generic implementation of showt.

Since: 2

genericShowtl :: (Generic a, GTextShow Zero (Rep a)) => a -> Text

A Generic implementation of showtl.

Since: 2

genericShowtPrec :: (Generic a, GTextShow Zero (Rep a)) => Int -> a -> Text

A Generic implementation of showPrect.

Since: 2

genericShowtlPrec :: (Generic a, GTextShow Zero (Rep a)) => Int -> a -> Text

A Generic implementation of showtlPrec.

Since: 2

genericShowtList :: (Generic a, GTextShow Zero (Rep a)) => [a] -> Text

A Generic implementation of showtList.

Since: 2

genericShowtlList :: (Generic a, GTextShow Zero (Rep a)) => [a] -> Text

A Generic implementation of showtlList.

Since: 2

genericShowb :: (Generic a, GTextShow Zero (Rep a)) => a -> Builder

A Generic implementation of showb.

Since: 2

genericShowbPrec :: (Generic a, GTextShow Zero (Rep a)) => Int -> a -> Builder

A Generic implementation of showbPrec.

Since: 2

genericShowbList :: (Generic a, GTextShow Zero (Rep a)) => [a] -> Builder

A Generic implementation of showbList.

Since: 2

genericPrintT :: (Generic a, GTextShow Zero (Rep a)) => a -> IO ()

A Generic implementation of printT.

Since: 2

genericPrintTL :: (Generic a, GTextShow Zero (Rep a)) => a -> IO ()

A Generic implementation of printTL.

Since: 2

genericHPrintT :: (Generic a, GTextShow Zero (Rep a)) => Handle -> a -> IO ()

A Generic implementation of hPrintT.

Since: 2

genericHPrintTL :: (Generic a, GTextShow Zero (Rep a)) => Handle -> a -> IO ()

A Generic implementation of hPrintTL.

Since: 2

genericLiftShowbPrec :: (Generic1 f, GTextShow One (Rep1 f)) => (Int -> a -> Builder) -> ([a] -> Builder) -> Int -> f a -> Builder

A Generic1 implementation of genericLiftShowbPrec.

Since: 2

genericShowbPrec1 :: (Generic a, Generic1 f, GTextShow Zero (Rep a), GTextShow One (Rep1 f)) => Int -> f a -> Builder

A 'Generic'/'Generic1' implementation of showbPrec1.

Since: 2

GTextShow and friends

class GTextShow arity f where

Class of generic representation types that can be converted to a Builder. The arity type variable indicates which type class is used. GTextShow Zero indicates TextShow behavior, and GTextShow One indicates TextShow1 behavior.

Since: 3.2

Minimal complete definition

gShowbPrec

Methods

gShowbPrec :: ShowFuns arity a -> Int -> f a -> Builder

This is used as the default generic implementation of showbPrec (if the arity is Zero) or liftShowbPrec (if the arity is One).

Instances

GTextShow One V1

Methods

gShowbPrec :: ShowFuns One a -> Int -> V1 a -> Builder

GTextShow Zero V1

Methods

gShowbPrec :: ShowFuns Zero a -> Int -> V1 a -> Builder

(Constructor Meta c, GTextShowCon arity f, IsNullary * f) => GTextShow arity (C1 c f)

Methods

gShowbPrec :: ShowFuns arity a -> Int -> C1 c f a -> Builder

(GTextShow arity f, GTextShow arity g) => GTextShow arity ((:+:) f g)

Methods

gShowbPrec :: ShowFuns arity a -> Int -> (f :+: g) a -> Builder

GTextShow arity f => GTextShow arity (D1 d f)

Methods

gShowbPrec :: ShowFuns arity a -> Int -> D1 d f a -> Builder

class GTextShowCon arity f where

Class of generic representation types for which the ConType has been determined. The arity type variable indicates which type class is used. GTextShow Zero indicates TextShow behavior, and GTextShow One indicates TextShow1 behavior.

Minimal complete definition

gShowbPrecCon

Methods

gShowbPrecCon :: ConType -> ShowFuns arity a -> Int -> f a -> Builder

Convert value of a specific ConType to a Builder with the given precedence.

Instances

GTextShowCon arity UWord

Methods

gShowbPrecCon :: ConType -> ShowFuns arity a -> Int -> UWord a -> Builder

GTextShowCon arity UInt

Methods

gShowbPrecCon :: ConType -> ShowFuns arity a -> Int -> UInt a -> Builder

GTextShowCon arity UFloat

Methods

gShowbPrecCon :: ConType -> ShowFuns arity a -> Int -> UFloat a -> Builder

GTextShowCon arity UDouble

Methods

gShowbPrecCon :: ConType -> ShowFuns arity a -> Int -> UDouble a -> Builder

GTextShowCon arity UChar

Methods

gShowbPrecCon :: ConType -> ShowFuns arity a -> Int -> UChar a -> Builder

GTextShowCon arity U1

Methods

gShowbPrecCon :: ConType -> ShowFuns arity a -> Int -> U1 a -> Builder

GTextShowCon One Par1

Methods

gShowbPrecCon :: ConType -> ShowFuns One a -> Int -> Par1 a -> Builder

TextShow1 f => GTextShowCon One (Rec1 f)

Methods

gShowbPrecCon :: ConType -> ShowFuns One a -> Int -> Rec1 f a -> Builder

(GTextShowCon arity f, GTextShowCon arity g) => GTextShowCon arity ((:*:) f g)

Methods

gShowbPrecCon :: ConType -> ShowFuns arity a -> Int -> (f :*: g) a -> Builder

(Selector Meta s, GTextShowCon arity f) => GTextShowCon arity (S1 s f)

Methods

gShowbPrecCon :: ConType -> ShowFuns arity a -> Int -> S1 s f a -> Builder

TextShow c => GTextShowCon arity (K1 i c)

Methods

gShowbPrecCon :: ConType -> ShowFuns arity a -> Int -> K1 i c a -> Builder

(TextShow1 f, GTextShowCon One g) => GTextShowCon One ((:.:) f g)

Methods

gShowbPrecCon :: ConType -> ShowFuns One a -> Int -> (f :.: g) a -> Builder

class IsNullary f where

Class of generic representation types that represent a constructor with zero or more fields.

Minimal complete definition

isNullary

Methods

isNullary :: f a -> Bool

Instances

IsNullary * U1

Methods

isNullary :: f a -> Bool

IsNullary * UChar

Methods

isNullary :: f a -> Bool

IsNullary * UDouble

Methods

isNullary :: f a -> Bool

IsNullary * UFloat

Methods

isNullary :: f a -> Bool

IsNullary * UInt

Methods

isNullary :: f a -> Bool

IsNullary * UWord

Methods

isNullary :: f a -> Bool

IsNullary * (Rec1 f)

Methods

isNullary :: f a -> Bool

IsNullary * (K1 i c)

Methods

isNullary :: f a -> Bool

IsNullary * ((:*:) f g)

Methods

isNullary :: f a -> Bool

IsNullary * ((:.:) f g)

Methods

isNullary :: f a -> Bool

IsNullary * f => IsNullary * (S1 s f)

Methods

isNullary :: f a -> Bool

IsNullary * Par1

Methods

isNullary :: f a -> Bool

data ConType

Whether a constructor is a record (Rec), a tuple (Tup), is prefix (Pref), or infix (Inf).

Since: 2

Constructors

Rec

Tup

Pref

Inf String

Instances

Eq ConType

Methods

(==) :: ConType -> ConType -> Bool

(/=) :: ConType -> ConType -> Bool

Ord ConType

Methods

compare :: ConType -> ConType -> Ordering

(<) :: ConType -> ConType -> Bool

(<=) :: ConType -> ConType -> Bool

(>) :: ConType -> ConType -> Bool

(>=) :: ConType -> ConType -> Bool

max :: ConType -> ConType -> ConType

min :: ConType -> ConType -> ConType

Read ConType

Methods

readsPrec :: Int -> ReadS ConType

readList :: ReadS [ConType]

readPrec :: ReadPrec ConType

readListPrec :: ReadPrec [ConType]

Show ConType

Methods

showsPrec :: Int -> ConType -> ShowS

show :: ConType -> String

showList :: [ConType] -> ShowS

Generic ConType

Associated Types

type Rep ConType :: * -> *

Methods

from :: ConType -> Rep ConType x

to :: Rep ConType x -> ConType

Lift ConType

Methods

lift :: ConType -> Q Exp

TextShow ConType

Methods

showbPrec :: Int -> ConType -> Builder

showb :: ConType -> Builder

showbList :: [ConType] -> Builder

showtPrec :: Int -> ConType -> Text

showt :: ConType -> Text

showtList :: [ConType] -> Text

showtlPrec :: Int -> ConType -> Text

showtl :: ConType -> Text

showtlList :: [ConType] -> Text

type Rep ConType

type Rep ConType = D1 (MetaData "ConType" "TextShow.Generic" "text-show-3.3-bIZFsMsDGoDCqejfaz4KO" False) ((:+:) ((:+:) (C1 (MetaCons "Rec" PrefixI False) U1) (C1 (MetaCons "Tup" PrefixI False) U1)) ((:+:) (C1 (MetaCons "Pref" PrefixI False) U1) (C1 (MetaCons "Inf" PrefixI False) (S1 (MetaSel (Nothing Symbol) NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 String)))))

data ShowFuns arity a where

A ShowFuns value either stores nothing (for TextShow) or it stores the two function arguments that show occurrences of the type parameter (for TextShow1).

Since: 3.3

Constructors

NoShowFuns :: ShowFuns Zero a

Show1Funs :: (Int -> a -> Builder) -> ([a] -> Builder) -> ShowFuns One a

Instances

Contravariant (ShowFuns arity)

Methods

contramap :: (a -> b) -> ShowFuns arity b -> ShowFuns arity a

(>$) :: b -> ShowFuns arity b -> ShowFuns arity a

data Zero

A type-level indicator that TextShow is being derived generically.

Since: 3.2

Instances

GTextShow Zero V1

Methods

gShowbPrec :: ShowFuns Zero a -> Int -> V1 a -> Builder

data One

A type-level indicator that TextShow1 is being derived generically.

Since: 3.2

Instances

GTextShowCon One Par1

Methods

gShowbPrecCon :: ConType -> ShowFuns One a -> Int -> Par1 a -> Builder

GTextShow One V1

Methods

gShowbPrec :: ShowFuns One a -> Int -> V1 a -> Builder

TextShow1 f => GTextShowCon One (Rec1 f)

Methods

gShowbPrecCon :: ConType -> ShowFuns One a -> Int -> Rec1 f a -> Builder

(TextShow1 f, GTextShowCon One g) => GTextShowCon One ((:.:) f g)

Methods

gShowbPrecCon :: ConType -> ShowFuns One a -> Int -> (f :.: g) a -> Builder