{-# LANGUAGE BangPatterns       #-}
{-# LANGUAGE CPP                #-}
{-# LANGUAGE MagicHash          #-}
{-# LANGUAGE NamedFieldPuns     #-}
{-# LANGUAGE TemplateHaskell    #-}
{-|
Module:      TextShow.TH.Internal
Copyright:   (C) 2014-2017 Ryan Scott
License:     BSD-style (see the file LICENSE)
Maintainer:  Ryan Scott
Stability:   Provisional
Portability: GHC

Functions to mechanically derive 'TextShow', 'TextShow1', or 'TextShow2' instances,
or to splice their functions directly into Haskell source code. You need to enable
the @TemplateHaskell@ language extension in order to use this module.

This implementation is loosely based off of the @Data.Aeson.TH@ module from the
@aeson@ library.
-}
module TextShow.TH.Internal (
      -- * 'deriveTextShow'
      -- $deriveTextShow
      deriveTextShow
      -- * 'deriveTextShow1'
      -- $deriveTextShow1
    , deriveTextShow1
      -- * 'deriveTextShow2'
      -- $deriveTextShow2
    , deriveTextShow2
      -- * @make-@ functions
      -- $make
    , makeShowt
    , makeShowtl
    , makeShowtPrec
    , makeShowtlPrec
    , makeShowtList
    , makeShowtlList
    , makeShowb
    , makeShowbPrec
    , makeShowbList
    , makePrintT
    , makePrintTL
    , makeHPrintT
    , makeHPrintTL
    , makeLiftShowbPrec
    , makeShowbPrec1
    , makeLiftShowbPrec2
    , makeShowbPrec2
    -- * 'Options'
    , Options(..)
    , defaultOptions
    , GenTextMethods(..)
    , deriveTextShowOptions
    , deriveTextShow1Options
    , deriveTextShow2Options
    ) where

import           Control.Monad (unless, when)
import           Data.Foldable.Compat
import           Data.List.Compat
import qualified Data.List.NonEmpty.Compat as NE (reverse)
import           Data.List.NonEmpty.Compat (NonEmpty(..), (<|))
import qualified Data.Map as Map (fromList, keys, lookup, singleton)
import           Data.Map (Map)
import           Data.Maybe
import qualified Data.Set as Set
import           Data.Set (Set)
import qualified Data.Text    as TS
import qualified Data.Text.IO as TS (putStrLn, hPutStrLn)
import           Data.Text.Lazy (toStrict)
import qualified Data.Text.Lazy.Builder as TB
import           Data.Text.Lazy.Builder (Builder, toLazyText)
import qualified Data.Text.Lazy    as TL
import qualified Data.Text.Lazy.IO as TL (putStrLn, hPutStrLn)

import           GHC.Exts ( Char(..), Double(..), Float(..), Int(..), Word(..)
                          , Char#, Double#, Float#, Int#, Word#
#if MIN_VERSION_base(4,13,0)
                          , Int8#, Int16#, Word8#, Word16#
                          , extendInt8#, extendInt16#, extendWord8#, extendWord16#
#endif
                          )
import           GHC.Show (appPrec, appPrec1)

import           Language.Haskell.TH.Datatype
import           Language.Haskell.TH.Lib
import           Language.Haskell.TH.Ppr hiding (appPrec)
import           Language.Haskell.TH.Syntax

import           Prelude ()
import           Prelude.Compat

import           TextShow.Classes (TextShow(..), TextShow1(..), TextShow2(..),
                                   showbListWith,
                                   showbParen,  showbCommaSpace,  showbSpace,
                                   showtParen,  showtCommaSpace,  showtSpace,
                                   showtlParen, showtlCommaSpace, showtlSpace)
import           TextShow.Options (Options(..), GenTextMethods(..), defaultOptions)
import           TextShow.Utils (isInfixDataCon, isSymVar, isTupleString)

-------------------------------------------------------------------------------
-- User-facing API
-------------------------------------------------------------------------------

{- $deriveTextShow

'deriveTextShow' automatically generates a 'TextShow' instance declaration for a data
type, newtype, or data family instance. This emulates what would (hypothetically)
happen if you could attach a @deriving 'TextShow'@ clause to the end of a data
declaration.

Here are some examples of how to derive 'TextShow' for simple data types:

@
&#123;-&#35; LANGUAGE TemplateHaskell &#35;-&#125;
import TextShow.TH

data Letter = A | B | C
$('deriveTextShow' ''Letter) -- instance TextShow Letter where ...

newtype Box a = Box a
$('deriveTextShow' ''Box) -- instance TextShow a => TextShow (Box a) where ...
@

'deriveTextShow' can also be used to derive 'TextShow' instances for data family
instances (which requires the @-XTypeFamilies@ extension). To do so, pass the name of
a data or newtype instance constructor (NOT a data family name!) to 'deriveTextShow'.
Note that the generated code may require the @-XFlexibleInstances@ extension.
Some examples:

@
&#123;-&#35; LANGUAGE FlexibleInstances, TemplateHaskell, TypeFamilies &#35;-&#125;
import TextShow.TH (deriveTextShow)

class AssocClass a where
    data AssocData a
instance AssocClass Int where
    data AssocData Int = AssocDataInt1 Int | AssocDataInt2 Int Int
$('deriveTextShow' 'AssocDataInt1) -- instance TextShow (AssocData Int) where ...
-- Alternatively, one could use $(deriveTextShow 'AssocDataInt2)

data family DataFam a b
newtype instance DataFam () b = DataFamB b
$('deriveTextShow' 'DataFamB) -- instance TextShow b => TextShow (DataFam () b)
@

Note that at the moment, there are some limitations:

* The 'Name' argument to 'deriveTextShow' must not be a type synonym.

* 'deriveTextShow' makes the assumption that all type variables of kind @*@ require a
  'TextShow' constraint when creating the type context. For example, if you have @data
  Phantom a = Phantom@, then @('deriveTextShow' ''Phantom)@ will generate @instance
  'TextShow' a => 'TextShow' (Phantom a) where ...@, even though @'TextShow' a@ is
  not required. If you want a proper 'TextShow' instance for @Phantom@, you will need
  to use 'makeShowbPrec' (see the documentation of the @make@ functions for more
  information).

* 'deriveTextShow' lacks the ability to properly detect data types with higher-kinded
   type parameters (e.g., @data HK f a = HK (f a)@) or with kinds other than @*@
   (e.g., @data List a (empty :: Bool)@). If you wish to derive 'TextShow'
   instances for these data types, you will need to use 'makeShowbPrec'.

* Some data constructors have arguments whose 'TextShow' instance depends on a
  typeclass besides 'TextShow'. For example, consider @newtype MyFixed a = MyFixed
  (Fixed a)@. @'Fixed' a@ is a 'TextShow' instance only if @a@ is an instance of both
  @HasResolution@ and 'TextShow'. Unfortunately, 'deriveTextShow' cannot infer that
  'a' must be an instance of 'HasResolution', so it cannot create a 'TextShow'
  instance for @MyFixed@. However, you can use 'makeShowbPrec' to get around this.

-}

-- | Generates a 'TextShow' instance declaration for the given data type or data
-- family instance.
--
-- /Since: 2/
deriveTextShow :: Name -> Q [Dec]
deriveTextShow :: Name -> Q [Dec]
deriveTextShow = Options -> Name -> Q [Dec]
deriveTextShowOptions Options
defaultOptions

-- | Like 'deriveTextShow', but takes an 'Options' argument.
--
-- /Since: 3.4/
deriveTextShowOptions :: Options -> Name -> Q [Dec]
deriveTextShowOptions :: Options -> Name -> Q [Dec]
deriveTextShowOptions = TextShowClass -> Options -> Name -> Q [Dec]
deriveTextShowClass TextShowClass
TextShow

{- $deriveTextShow1

'deriveTextShow1' automatically generates a 'Show1' instance declaration for a data
type, newtype, or data family instance that has at least one type variable.
This emulates what would (hypothetically) happen if you could attach a @deriving
'TextShow1'@ clause to the end of a data declaration. Examples:

@
&#123;-&#35; LANGUAGE TemplateHaskell &#35;-&#125;
import TextShow.TH

data Stream a = Stream a (Stream a)
$('deriveTextShow1' ''Stream) -- instance TextShow1 TextStream where ...

newtype WrappedFunctor f a = WrapFunctor (f a)
$('deriveTextShow1' ''WrappedFunctor) -- instance TextShow1 f => TextShow1 (WrappedFunctor f) where ...
@

The same restrictions that apply to 'deriveTextShow' also apply to 'deriveTextShow1',
with some caveats:

* With 'deriveTextShow1', the last type variable must be of kind @*@. For other ones,
  type variables of kind @*@ are assumed to require a 'TextShow' context, and type
  variables of kind @* -> *@ are assumed to require a 'TextShow1' context. For more
  complicated scenarios, use 'makeLiftShowbPrec'.

* If using @-XDatatypeContexts@, a datatype constraint cannot mention the last type
  variable. For example, @data Ord a => Illegal a = Illegal a@ cannot have a derived
  'TextShow1' instance.

* If the last type variable is used within a data field of a constructor, it must only
  be used in the last argument of the data type constructor. For example, @data Legal a
  = Legal (Either Int a)@ can have a derived 'TextShow1' instance, but @data Illegal a
  = Illegal (Either a a)@ cannot.

* Data family instances must be able to eta-reduce the last type variable. In other
  words, if you have a instance of the form:

  @
  data family Family a1 ... an t
  data instance Family e1 ... e2 v = ...
  @

  Then the following conditions must hold:

  1. @v@ must be a type variable.
  2. @v@ must not be mentioned in any of @e1@, ..., @e2@.

-}

-- | Generates a 'TextShow1' instance declaration for the given data type or data
-- family instance.
--
-- /Since: 2/
deriveTextShow1 :: Name -> Q [Dec]
deriveTextShow1 :: Name -> Q [Dec]
deriveTextShow1 = Options -> Name -> Q [Dec]
deriveTextShow1Options Options
defaultOptions

-- | Like 'deriveTextShow1', but takes an 'Options' argument.
--
-- /Since: 3.4/
deriveTextShow1Options :: Options -> Name -> Q [Dec]
deriveTextShow1Options :: Options -> Name -> Q [Dec]
deriveTextShow1Options = TextShowClass -> Options -> Name -> Q [Dec]
deriveTextShowClass TextShowClass
TextShow1

{- $deriveTextShow2

'deriveTextShow2' automatically generates a 'TextShow2' instance declaration for a data
type, newtype, or data family instance that has at least two type variables.
This emulates what would (hypothetically) happen if you could attach a @deriving
'TextShow2'@ clause to the end of a data declaration. Examples:

@
&#123;-&#35; LANGUAGE TemplateHaskell &#35;-&#125;
import TextShow.TH

data OneOrNone a b = OneL a | OneR b | None
$('deriveTextShow2' ''OneOrNone) -- instance TextShow2 OneOrNone where ...

newtype WrappedBifunctor f a b = WrapBifunctor (f a b)
$('deriveTextShow2' ''WrappedBifunctor) -- instance TextShow2 f => TextShow2 (WrappedBifunctor f) where ...
@

The same restrictions that apply to 'deriveTextShow' and 'deriveTextShow1' also apply
to 'deriveTextShow2', with some caveats:

* With 'deriveTextShow2', the last type variables must both be of kind @*@. For other
  ones, type variables of kind @*@ are assumed to require a 'TextShow' constraint, type
  variables of kind @* -> *@ are assumed to require a 'TextShow1' constraint, and type
  variables of kind @* -> * -> *@ are assumed to require a 'TextShow2' constraint. For
  more complicated scenarios, use 'makeLiftShowbPrec2'.

* If using @-XDatatypeContexts@, a datatype constraint cannot mention either of the last
  two type variables. For example, @data Ord a => Illegal a b = Illegal a b@ cannot
  have a derived 'TextShow2' instance.

* If either of the last two type variables is used within a data field of a constructor,
  it must only be used in the last two arguments of the data type constructor. For
  example, @data Legal a b = Legal (Int, Int, a, b)@ can have a derived 'TextShow2'
  instance, but @data Illegal a b = Illegal (a, b, a, b)@ cannot.

* Data family instances must be able to eta-reduce the last two type variables. In other
  words, if you have a instance of the form:

  @
  data family Family a1 ... an t1 t2
  data instance Family e1 ... e2 v1 v2 = ...
  @

  Then the following conditions must hold:

  1. @v1@ and @v2@ must be distinct type variables.
  2. Neither @v1@ not @v2@ must be mentioned in any of @e1@, ..., @e2@.

-}

-- | Generates a 'TextShow2' instance declaration for the given data type or data
-- family instance.
--
-- /Since: 2/
deriveTextShow2 :: Name -> Q [Dec]
deriveTextShow2 :: Name -> Q [Dec]
deriveTextShow2 = Options -> Name -> Q [Dec]
deriveTextShow2Options Options
defaultOptions

-- | Like 'deriveTextShow2', but takes an 'Options' argument.
--
-- /Since: 3.4/
deriveTextShow2Options :: Options -> Name -> Q [Dec]
deriveTextShow2Options :: Options -> Name -> Q [Dec]
deriveTextShow2Options = TextShowClass -> Options -> Name -> Q [Dec]
deriveTextShowClass TextShowClass
TextShow2

{- $make

There may be scenarios in which you want to show an arbitrary data type or data
family instance without having to make the type an instance of 'TextShow'. For these
cases, this modules provides several functions (all prefixed with @make@-) that
splice the appropriate lambda expression into your source code. Example:

This is particularly useful for creating instances for sophisticated data types. For
example, 'deriveTextShow' cannot infer the correct type context for
@newtype HigherKinded f a = HigherKinded (f a)@, since @f@ is of kind @* -> *@.
However, it is still possible to derive a 'TextShow' instance for @HigherKinded@
without too much trouble using 'makeShowbPrec':

@
&#123;-&#35; LANGUAGE FlexibleContexts, TemplateHaskell &#35;-&#125;
import TextShow
import TextShow.TH

instance TextShow (f a) => TextShow (HigherKinded f a) where
    showbPrec = $(makeShowbPrec ''HigherKinded)
@

-}

-- | Generates a lambda expression which behaves like 'showt' (without requiring a
-- 'TextShow' instance).
--
-- /Since: 2/
makeShowt :: Name -> Q Exp
makeShowt :: Name -> Q Exp
makeShowt name :: Name
name = Name -> Q Exp
makeShowtPrec Name
name Q Exp -> Q Exp -> Q Exp
`appE` Int -> Q Exp
integerE 0

-- | Generates a lambda expression which behaves like 'showtl' (without requiring a
-- 'TextShow' instance).
--
-- /Since: 2/
makeShowtl :: Name -> Q Exp
makeShowtl :: Name -> Q Exp
makeShowtl name :: Name
name = Name -> Q Exp
makeShowtlPrec Name
name Q Exp -> Q Exp -> Q Exp
`appE` Int -> Q Exp
integerE 0

-- | Generates a lambda expression which behaves like 'showtPrec' (without requiring a
-- 'TextShow' instance).
--
-- /Since: 2/
makeShowtPrec :: Name -> Q Exp
makeShowtPrec :: Name -> Q Exp
makeShowtPrec = TextShowClass -> TextShowFun -> Options -> Name -> Q Exp
makeShowbPrecClass TextShowClass
TextShow TextShowFun
ShowtPrec Options
defaultOptions

-- | Generates a lambda expression which behaves like 'showtlPrec' (without
-- requiring a 'TextShow' instance).
--
-- /Since: 2/
makeShowtlPrec :: Name -> Q Exp
makeShowtlPrec :: Name -> Q Exp
makeShowtlPrec = TextShowClass -> TextShowFun -> Options -> Name -> Q Exp
makeShowbPrecClass TextShowClass
TextShow TextShowFun
ShowtlPrec Options
defaultOptions

-- | Generates a lambda expression which behaves like 'showtList' (without requiring a
-- 'TextShow' instance).
--
-- /Since: 2/
makeShowtList :: Name -> Q Exp
makeShowtList :: Name -> Q Exp
makeShowtList name :: Name
name = [| toStrict . $(makeShowtlList name) |]

-- | Generates a lambda expression which behaves like 'showtlList' (without
-- requiring a 'TextShow' instance).
--
-- /Since: 2/
makeShowtlList :: Name -> Q Exp
makeShowtlList :: Name -> Q Exp
makeShowtlList name :: Name
name = [| toLazyText . $(makeShowbList name) |]

-- | Generates a lambda expression which behaves like 'showb' (without requiring a
-- 'TextShow' instance).
--
-- /Since: 2/
makeShowb :: Name -> Q Exp
makeShowb :: Name -> Q Exp
makeShowb name :: Name
name = Name -> Q Exp
makeShowbPrec Name
name Q Exp -> Q Exp -> Q Exp
`appE` Int -> Q Exp
integerE 0

-- | Generates a lambda expression which behaves like 'showbPrec' (without requiring a
-- 'TextShow' instance).
--
-- /Since: 2/
makeShowbPrec :: Name -> Q Exp
makeShowbPrec :: Name -> Q Exp
makeShowbPrec = TextShowClass -> TextShowFun -> Options -> Name -> Q Exp
makeShowbPrecClass TextShowClass
TextShow TextShowFun
ShowbPrec Options
defaultOptions

-- | Generates a lambda expression which behaves like 'liftShowbPrec' (without
-- requiring a 'TextShow1' instance).
--
-- /Since: 3/
makeLiftShowbPrec :: Name -> Q Exp
makeLiftShowbPrec :: Name -> Q Exp
makeLiftShowbPrec = TextShowClass -> TextShowFun -> Options -> Name -> Q Exp
makeShowbPrecClass TextShowClass
TextShow1 TextShowFun
ShowbPrec Options
defaultOptions

-- | Generates a lambda expression which behaves like 'showbPrec1' (without
-- requiring a 'TextShow1' instance).
--
-- /Since: 2/
makeShowbPrec1 :: Name -> Q Exp
makeShowbPrec1 :: Name -> Q Exp
makeShowbPrec1 name :: Name
name = [| $(makeLiftShowbPrec name) showbPrec showbList |]

-- | Generates a lambda expression which behaves like 'liftShowbPrec2' (without
-- requiring a 'TextShow2' instance).
--
-- /Since: 3/
makeLiftShowbPrec2 :: Name -> Q Exp
makeLiftShowbPrec2 :: Name -> Q Exp
makeLiftShowbPrec2 = TextShowClass -> TextShowFun -> Options -> Name -> Q Exp
makeShowbPrecClass TextShowClass
TextShow2 TextShowFun
ShowbPrec Options
defaultOptions

-- | Generates a lambda expression which behaves like 'showbPrec2' (without
-- requiring a 'TextShow2' instance).
--
-- /Since: 2/
makeShowbPrec2 :: Name -> Q Exp
makeShowbPrec2 :: Name -> Q Exp
makeShowbPrec2 name :: Name
name = [| $(makeLiftShowbPrec2 name) showbPrec showbList showbPrec showbList |]

-- | Generates a lambda expression which behaves like 'showbList' (without requiring a
-- 'TextShow' instance).
--
-- /Since: 2/
makeShowbList :: Name -> Q Exp
makeShowbList :: Name -> Q Exp
makeShowbList name :: Name
name = [| showbListWith $(makeShowb name) |]

-- | Generates a lambda expression which behaves like 'printT' (without requiring a
-- 'TextShow' instance).
--
-- /Since: 2/
makePrintT :: Name -> Q Exp
makePrintT :: Name -> Q Exp
makePrintT name :: Name
name = [| TS.putStrLn . $(makeShowt name) |]

-- | Generates a lambda expression which behaves like 'printTL' (without requiring a
-- 'TextShow' instance).
--
-- /Since: 2/
makePrintTL :: Name -> Q Exp
makePrintTL :: Name -> Q Exp
makePrintTL name :: Name
name = [| TL.putStrLn . $(makeShowtl name) |]

-- | Generates a lambda expression which behaves like 'hPrintT' (without requiring a
-- 'TextShow' instance).
--
-- /Since: 2/
makeHPrintT :: Name -> Q Exp
makeHPrintT :: Name -> Q Exp
makeHPrintT name :: Name
name = [| \h -> TS.hPutStrLn h . $(makeShowt name) |]

-- | Generates a lambda expression which behaves like 'hPrintTL' (without
-- requiring a 'TextShow' instance).
--
-- /Since: 2/
makeHPrintTL :: Name -> Q Exp
makeHPrintTL :: Name -> Q Exp
makeHPrintTL name :: Name
name = [| \h -> TL.hPutStrLn h . $(makeShowtl name) |]

-------------------------------------------------------------------------------
-- Code generation
-------------------------------------------------------------------------------

-- | Derive a TextShow(1)(2) instance declaration (depending on the TextShowClass
-- argument's value).
deriveTextShowClass :: TextShowClass -> Options -> Name -> Q [Dec]
deriveTextShowClass :: TextShowClass -> Options -> Name -> Q [Dec]
deriveTextShowClass tsClass :: TextShowClass
tsClass opts :: Options
opts name :: Name
name = do
  DatatypeInfo
info <- Name -> Q DatatypeInfo
reifyDatatype Name
name
  case DatatypeInfo
info of
    DatatypeInfo { datatypeContext :: DatatypeInfo -> Cxt
datatypeContext   = Cxt
ctxt
                 , datatypeName :: DatatypeInfo -> Name
datatypeName      = Name
parentName
                 , datatypeInstTypes :: DatatypeInfo -> Cxt
datatypeInstTypes = Cxt
instTys
                 , datatypeVariant :: DatatypeInfo -> DatatypeVariant
datatypeVariant   = DatatypeVariant
variant
                 , datatypeCons :: DatatypeInfo -> [ConstructorInfo]
datatypeCons      = [ConstructorInfo]
cons
                 } -> do
      (instanceCxt :: Cxt
instanceCxt, instanceType :: Type
instanceType)
        <- TextShowClass
-> Name -> Cxt -> Cxt -> DatatypeVariant -> Q (Cxt, Type)
buildTypeInstance TextShowClass
tsClass Name
parentName Cxt
ctxt Cxt
instTys DatatypeVariant
variant
      (Dec -> [Dec] -> [Dec]
forall a. a -> [a] -> [a]
:[]) (Dec -> [Dec]) -> Q Dec -> Q [Dec]
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> CxtQ -> TypeQ -> [Q Dec] -> Q Dec
instanceD (Cxt -> CxtQ
forall (m :: * -> *) a. Monad m => a -> m a
return Cxt
instanceCxt)
                          (Type -> TypeQ
forall (m :: * -> *) a. Monad m => a -> m a
return Type
instanceType)
                          (TextShowClass -> Options -> Cxt -> [ConstructorInfo] -> [Q Dec]
showbPrecDecs TextShowClass
tsClass Options
opts Cxt
instTys [ConstructorInfo]
cons)

-- | Generates a declaration defining the primary function corresponding to a
-- particular class (showbPrec for TextShow, liftShowbPrec for TextShow1, and
-- liftShowbPrec2 for TextShow2).
showbPrecDecs :: TextShowClass -> Options -> [Type] -> [ConstructorInfo] -> [Q Dec]
showbPrecDecs :: TextShowClass -> Options -> Cxt -> [ConstructorInfo] -> [Q Dec]
showbPrecDecs tsClass :: TextShowClass
tsClass opts :: Options
opts instTys :: Cxt
instTys cons :: [ConstructorInfo]
cons =
    [TextShowFun -> Name -> Q Dec
genMethod TextShowFun
ShowbPrec (TextShowClass -> Name
showbPrecName TextShowClass
tsClass)]
    [Q Dec] -> [Q Dec] -> [Q Dec]
forall a. [a] -> [a] -> [a]
++ if TextShowClass
tsClass TextShowClass -> TextShowClass -> Bool
forall a. Eq a => a -> a -> Bool
== TextShowClass
TextShow Bool -> Bool -> Bool
&& Bool
shouldGenTextMethods
          then [TextShowFun -> Name -> Q Dec
genMethod TextShowFun
ShowtPrec 'showtPrec, TextShowFun -> Name -> Q Dec
genMethod TextShowFun
ShowtlPrec 'showtlPrec]
          else []
  where
    shouldGenTextMethods :: Bool
    shouldGenTextMethods :: Bool
shouldGenTextMethods = case Options -> GenTextMethods
genTextMethods Options
opts of
      AlwaysTextMethods    -> Bool
True
      SometimesTextMethods -> (ConstructorInfo -> Bool) -> [ConstructorInfo] -> Bool
forall (t :: * -> *) a. Foldable t => (a -> Bool) -> t a -> Bool
all ConstructorInfo -> Bool
isNullaryCon [ConstructorInfo]
cons
      NeverTextMethods     -> Bool
False

    genMethod :: TextShowFun -> Name -> Q Dec
    genMethod :: TextShowFun -> Name -> Q Dec
genMethod method :: TextShowFun
method methodName :: Name
methodName
      = Name -> [ClauseQ] -> Q Dec
funD Name
methodName
             [ [PatQ] -> BodyQ -> [Q Dec] -> ClauseQ
clause []
                      (Q Exp -> BodyQ
normalB (Q Exp -> BodyQ) -> Q Exp -> BodyQ
forall a b. (a -> b) -> a -> b
$ TextShowClass
-> TextShowFun -> Options -> Cxt -> [ConstructorInfo] -> Q Exp
makeTextShowForCons TextShowClass
tsClass TextShowFun
method Options
opts Cxt
instTys [ConstructorInfo]
cons)
                      []
             ]


-- | Generates a lambda expression which behaves like showbPrec (for TextShow),
-- liftShowbPrec (for TextShow1), or liftShowbPrec2 (for TextShow2).
makeShowbPrecClass :: TextShowClass -> TextShowFun -> Options -> Name -> Q Exp
makeShowbPrecClass :: TextShowClass -> TextShowFun -> Options -> Name -> Q Exp
makeShowbPrecClass tsClass :: TextShowClass
tsClass tsFun :: TextShowFun
tsFun opts :: Options
opts name :: Name
name = do
  DatatypeInfo
info <- Name -> Q DatatypeInfo
reifyDatatype Name
name
  case DatatypeInfo
info of
    DatatypeInfo { datatypeContext :: DatatypeInfo -> Cxt
datatypeContext   = Cxt
ctxt
                 , datatypeName :: DatatypeInfo -> Name
datatypeName      = Name
parentName
                 , datatypeInstTypes :: DatatypeInfo -> Cxt
datatypeInstTypes = Cxt
instTys
                 , datatypeVariant :: DatatypeInfo -> DatatypeVariant
datatypeVariant   = DatatypeVariant
variant
                 , datatypeCons :: DatatypeInfo -> [ConstructorInfo]
datatypeCons      = [ConstructorInfo]
cons
                 } ->
      -- We force buildTypeInstance here since it performs some checks for whether
      -- or not the provided datatype can actually have showbPrec/liftShowbPrec/etc.
      -- implemented for it, and produces errors if it can't.
      TextShowClass
-> Name -> Cxt -> Cxt -> DatatypeVariant -> Q (Cxt, Type)
buildTypeInstance TextShowClass
tsClass Name
parentName Cxt
ctxt Cxt
instTys DatatypeVariant
variant
        Q (Cxt, Type) -> Q Exp -> Q Exp
forall (m :: * -> *) a b. Monad m => m a -> m b -> m b
>> TextShowClass
-> TextShowFun -> Options -> Cxt -> [ConstructorInfo] -> Q Exp
makeTextShowForCons TextShowClass
tsClass TextShowFun
tsFun Options
opts Cxt
instTys [ConstructorInfo]
cons

-- | Generates a lambda expression for showbPrec/liftShowbPrec/etc. for the
-- given constructors. All constructors must be from the same type.
makeTextShowForCons :: TextShowClass -> TextShowFun -> Options -> [Type] -> [ConstructorInfo]
                    -> Q Exp
makeTextShowForCons :: TextShowClass
-> TextShowFun -> Options -> Cxt -> [ConstructorInfo] -> Q Exp
makeTextShowForCons tsClass :: TextShowClass
tsClass tsFun :: TextShowFun
tsFun opts :: Options
opts instTys :: Cxt
instTys cons :: [ConstructorInfo]
cons = do
    Name
p       <- String -> Q Name
newName "p"
    Name
value   <- String -> Q Name
newName "value"
    [Name]
sps     <- String -> Int -> Q [Name]
newNameList "sp" (Int -> Q [Name]) -> Int -> Q [Name]
forall a b. (a -> b) -> a -> b
$ TextShowClass -> Int
forall a. Enum a => a -> Int
fromEnum TextShowClass
tsClass
    [Name]
sls     <- String -> Int -> Q [Name]
newNameList "sl" (Int -> Q [Name]) -> Int -> Q [Name]
forall a b. (a -> b) -> a -> b
$ TextShowClass -> Int
forall a. Enum a => a -> Int
fromEnum TextShowClass
tsClass
    let spls :: [(Name, Name)]
spls       = [Name] -> [Name] -> [(Name, Name)]
forall a b. [a] -> [b] -> [(a, b)]
zip [Name]
sps [Name]
sls
        spsAndSls :: [Name]
spsAndSls  = [Name] -> [Name] -> [Name]
forall a. [a] -> [a] -> [a]
interleave [Name]
sps [Name]
sls
        lastTyVars :: [Name]
lastTyVars = (Type -> Name) -> Cxt -> [Name]
forall a b. (a -> b) -> [a] -> [b]
map Type -> Name
varTToName (Cxt -> [Name]) -> Cxt -> [Name]
forall a b. (a -> b) -> a -> b
$ Int -> Cxt -> Cxt
forall a. Int -> [a] -> [a]
drop (Cxt -> Int
forall (t :: * -> *) a. Foldable t => t a -> Int
length Cxt
instTys Int -> Int -> Int
forall a. Num a => a -> a -> a
- TextShowClass -> Int
forall a. Enum a => a -> Int
fromEnum TextShowClass
tsClass) Cxt
instTys
        splMap :: Map Name (Name, Name)
splMap     = [(Name, (Name, Name))] -> Map Name (Name, Name)
forall k a. Ord k => [(k, a)] -> Map k a
Map.fromList ([(Name, (Name, Name))] -> Map Name (Name, Name))
-> [(Name, (Name, Name))] -> Map Name (Name, Name)
forall a b. (a -> b) -> a -> b
$ [Name] -> [(Name, Name)] -> [(Name, (Name, Name))]
forall a b. [a] -> [b] -> [(a, b)]
zip [Name]
lastTyVars [(Name, Name)]
spls

        makeFun :: Q Exp
makeFun
          | [ConstructorInfo] -> Bool
forall (t :: * -> *) a. Foldable t => t a -> Bool
null [ConstructorInfo]
cons Bool -> Bool -> Bool
&& Options -> Bool
emptyCaseBehavior Options
opts Bool -> Bool -> Bool
&& Bool
ghc7'8OrLater
          = Q Exp -> [MatchQ] -> Q Exp
caseE (Name -> Q Exp
varE Name
value) []

          | [ConstructorInfo] -> Bool
forall (t :: * -> *) a. Foldable t => t a -> Bool
null [ConstructorInfo]
cons
          = Q Exp -> Q Exp -> Q Exp
appE (Name -> Q Exp
varE 'seq) (Name -> Q Exp
varE Name
value) Q Exp -> Q Exp -> Q Exp
`appE`
            Q Exp -> Q Exp -> Q Exp
appE (Name -> Q Exp
varE 'error)
                 (String -> Q Exp
stringE (String -> Q Exp) -> String -> Q Exp
forall a b. (a -> b) -> a -> b
$ "Void " String -> String -> String
forall a. [a] -> [a] -> [a]
++ Name -> String
nameBase (TextShowClass -> TextShowFun -> Name
showPrecName TextShowClass
tsClass TextShowFun
tsFun))

          | Bool
otherwise
          = Q Exp -> [MatchQ] -> Q Exp
caseE (Name -> Q Exp
varE Name
value)
                  ((ConstructorInfo -> MatchQ) -> [ConstructorInfo] -> [MatchQ]
forall a b. (a -> b) -> [a] -> [b]
map (Name
-> TextShowClass
-> TextShowFun
-> Map Name (Name, Name)
-> ConstructorInfo
-> MatchQ
makeTextShowForCon Name
p TextShowClass
tsClass TextShowFun
tsFun Map Name (Name, Name)
splMap) [ConstructorInfo]
cons)

    [PatQ] -> Q Exp -> Q Exp
lamE ((Name -> PatQ) -> [Name] -> [PatQ]
forall a b. (a -> b) -> [a] -> [b]
map Name -> PatQ
varP ([Name] -> [PatQ]) -> [Name] -> [PatQ]
forall a b. (a -> b) -> a -> b
$ [Name]
spsAndSls [Name] -> [Name] -> [Name]
forall a. [a] -> [a] -> [a]
++ [Name
p, Name
value])
        (Q Exp -> Q Exp) -> ([Q Exp] -> Q Exp) -> [Q Exp] -> Q Exp
forall b c a. (b -> c) -> (a -> b) -> a -> c
. [Q Exp] -> Q Exp
appsE
        ([Q Exp] -> Q Exp) -> [Q Exp] -> Q Exp
forall a b. (a -> b) -> a -> b
$ [ Name -> Q Exp
varE (Name -> Q Exp) -> Name -> Q Exp
forall a b. (a -> b) -> a -> b
$ TextShowClass -> TextShowFun -> Name
showPrecConstName TextShowClass
tsClass TextShowFun
tsFun
          , Q Exp
makeFun
          ] [Q Exp] -> [Q Exp] -> [Q Exp]
forall a. [a] -> [a] -> [a]
++ (Name -> Q Exp) -> [Name] -> [Q Exp]
forall a b. (a -> b) -> [a] -> [b]
map Name -> Q Exp
varE [Name]
spsAndSls
            [Q Exp] -> [Q Exp] -> [Q Exp]
forall a. [a] -> [a] -> [a]
++ [Name -> Q Exp
varE Name
p, Name -> Q Exp
varE Name
value]
  where
    ghc7'8OrLater :: Bool
#if __GLASGOW_HASKELL__ >= 708
    ghc7'8OrLater :: Bool
ghc7'8OrLater = Bool
True
#else
    ghc7'8OrLater = False
#endif

-- | Generates a lambda expression for howbPrec/liftShowbPrec/etc. for a
-- single constructor.
makeTextShowForCon :: Name
                   -> TextShowClass
                   -> TextShowFun
                   -> TyVarMap
                   -> ConstructorInfo
                   -> Q Match
makeTextShowForCon :: Name
-> TextShowClass
-> TextShowFun
-> Map Name (Name, Name)
-> ConstructorInfo
-> MatchQ
makeTextShowForCon _ _ tsFun :: TextShowFun
tsFun _
  (ConstructorInfo { constructorName :: ConstructorInfo -> Name
constructorName = Name
conName, constructorFields :: ConstructorInfo -> Cxt
constructorFields = [] }) =
    PatQ -> BodyQ -> [Q Dec] -> MatchQ
match
      (Name -> [PatQ] -> PatQ
conP Name
conName [])
      (Q Exp -> BodyQ
normalB  (Q Exp -> BodyQ) -> Q Exp -> BodyQ
forall a b. (a -> b) -> a -> b
$ Name -> Q Exp
varE (TextShowFun -> Name
fromStringName TextShowFun
tsFun) Q Exp -> Q Exp -> Q Exp
`appE` String -> Q Exp
stringE (Name -> String -> String
parenInfixConName Name
conName ""))
      []
makeTextShowForCon p :: Name
p tsClass :: TextShowClass
tsClass tsFun :: TextShowFun
tsFun tvMap :: Map Name (Name, Name)
tvMap
  (ConstructorInfo { constructorName :: ConstructorInfo -> Name
constructorName    = Name
conName
                   , constructorVariant :: ConstructorInfo -> ConstructorVariant
constructorVariant = ConstructorVariant
NormalConstructor
                   , constructorFields :: ConstructorInfo -> Cxt
constructorFields  = [argTy :: Type
argTy] }) = do
    Type
argTy' <- Type -> TypeQ
resolveTypeSynonyms Type
argTy
    Name
arg <- String -> Q Name
newName "arg"

    let showArg :: Q Exp
showArg  = Int
-> TextShowClass
-> TextShowFun
-> Name
-> Map Name (Name, Name)
-> Type
-> Name
-> Q Exp
makeTextShowForArg Int
appPrec1 TextShowClass
tsClass TextShowFun
tsFun Name
conName Map Name (Name, Name)
tvMap Type
argTy' Name
arg
        namedArg :: Q Exp
namedArg = Q Exp -> Q Exp -> Q Exp -> Q Exp
infixApp (Name -> Q Exp
varE (TextShowFun -> Name
fromStringName TextShowFun
tsFun) Q Exp -> Q Exp -> Q Exp
`appE` String -> Q Exp
stringE (Name -> String -> String
parenInfixConName Name
conName " "))
                            [| (<>) |]
                            Q Exp
showArg

    PatQ -> BodyQ -> [Q Dec] -> MatchQ
match
      (Name -> [PatQ] -> PatQ
conP Name
conName [Name -> PatQ
varP Name
arg])
      (Q Exp -> BodyQ
normalB (Q Exp -> BodyQ) -> Q Exp -> BodyQ
forall a b. (a -> b) -> a -> b
$ Name -> Q Exp
varE (TextShowFun -> Name
showParenName TextShowFun
tsFun)
                  Q Exp -> Q Exp -> Q Exp
`appE` Q Exp -> Q Exp -> Q Exp -> Q Exp
infixApp (Name -> Q Exp
varE Name
p) [| (>) |] (Int -> Q Exp
integerE Int
appPrec)
                  Q Exp -> Q Exp -> Q Exp
`appE` Q Exp
namedArg)
      []
makeTextShowForCon p :: Name
p tsClass :: TextShowClass
tsClass tsFun :: TextShowFun
tsFun tvMap :: Map Name (Name, Name)
tvMap
  (ConstructorInfo { constructorName :: ConstructorInfo -> Name
constructorName    = Name
conName
                   , constructorVariant :: ConstructorInfo -> ConstructorVariant
constructorVariant = ConstructorVariant
NormalConstructor
                   , constructorFields :: ConstructorInfo -> Cxt
constructorFields  = Cxt
argTys }) = do
    Cxt
argTys' <- (Type -> TypeQ) -> Cxt -> CxtQ
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
mapM Type -> TypeQ
resolveTypeSynonyms Cxt
argTys
    [Name]
args <- String -> Int -> Q [Name]
newNameList "arg" (Int -> Q [Name]) -> Int -> Q [Name]
forall a b. (a -> b) -> a -> b
$ Cxt -> Int
forall (t :: * -> *) a. Foldable t => t a -> Int
length Cxt
argTys'

    if Name -> Bool
isNonUnitTuple Name
conName
       then do
         let showArgs :: [Q Exp]
showArgs       = (Type -> Name -> Q Exp) -> Cxt -> [Name] -> [Q Exp]
forall a b c. (a -> b -> c) -> [a] -> [b] -> [c]
zipWith (Int
-> TextShowClass
-> TextShowFun
-> Name
-> Map Name (Name, Name)
-> Type
-> Name
-> Q Exp
makeTextShowForArg 0 TextShowClass
tsClass TextShowFun
tsFun Name
conName Map Name (Name, Name)
tvMap) Cxt
argTys' [Name]
args
             parenCommaArgs :: [Q Exp]
parenCommaArgs = (Name -> Q Exp
varE (TextShowFun -> Name
singletonName TextShowFun
tsFun) Q Exp -> Q Exp -> Q Exp
`appE` Char -> Q Exp
charE '(')
                              Q Exp -> [Q Exp] -> [Q Exp]
forall a. a -> [a] -> [a]
: Q Exp -> [Q Exp] -> [Q Exp]
forall a. a -> [a] -> [a]
intersperse (Name -> Q Exp
varE (TextShowFun -> Name
singletonName TextShowFun
tsFun) Q Exp -> Q Exp -> Q Exp
`appE` Char -> Q Exp
charE ',') [Q Exp]
showArgs
             mappendArgs :: Q Exp
mappendArgs    = (Q Exp -> Q Exp -> Q Exp) -> Q Exp -> [Q Exp] -> Q Exp
forall (t :: * -> *) a b.
Foldable t =>
(a -> b -> b) -> b -> t a -> b
foldr' (Q Exp -> Q Exp -> Q Exp -> Q Exp
`infixApp` [| (<>) |])
                                     (Name -> Q Exp
varE (TextShowFun -> Name
singletonName TextShowFun
tsFun) Q Exp -> Q Exp -> Q Exp
`appE` Char -> Q Exp
charE ')')
                                     [Q Exp]
parenCommaArgs

         PatQ -> BodyQ -> [Q Dec] -> MatchQ
match (Name -> [PatQ] -> PatQ
conP Name
conName ([PatQ] -> PatQ) -> [PatQ] -> PatQ
forall a b. (a -> b) -> a -> b
$ (Name -> PatQ) -> [Name] -> [PatQ]
forall a b. (a -> b) -> [a] -> [b]
map Name -> PatQ
varP [Name]
args)
               (Q Exp -> BodyQ
normalB Q Exp
mappendArgs)
               []
       else do
         let showArgs :: [Q Exp]
showArgs    = (Type -> Name -> Q Exp) -> Cxt -> [Name] -> [Q Exp]
forall a b c. (a -> b -> c) -> [a] -> [b] -> [c]
zipWith (Int
-> TextShowClass
-> TextShowFun
-> Name
-> Map Name (Name, Name)
-> Type
-> Name
-> Q Exp
makeTextShowForArg Int
appPrec1 TextShowClass
tsClass TextShowFun
tsFun Name
conName Map Name (Name, Name)
tvMap) Cxt
argTys' [Name]
args
             mappendArgs :: Q Exp
mappendArgs = (Q Exp -> Q Exp -> Q Exp) -> [Q Exp] -> Q Exp
forall (t :: * -> *) a. Foldable t => (a -> a -> a) -> t a -> a
foldr1 (\v :: Q Exp
v q :: Q Exp
q -> Q Exp -> Q Exp -> Q Exp -> Q Exp
infixApp Q Exp
v
                                                    [| (<>) |]
                                                    (Q Exp -> Q Exp -> Q Exp -> Q Exp
infixApp (Name -> Q Exp
varE (Name -> Q Exp) -> Name -> Q Exp
forall a b. (a -> b) -> a -> b
$ TextShowFun -> Name
showSpaceName TextShowFun
tsFun)
                                                              [| (<>) |]
                                                              Q Exp
q)) [Q Exp]
showArgs
             namedArgs :: Q Exp
namedArgs   = Q Exp -> Q Exp -> Q Exp -> Q Exp
infixApp (Name -> Q Exp
varE (TextShowFun -> Name
fromStringName TextShowFun
tsFun) Q Exp -> Q Exp -> Q Exp
`appE` String -> Q Exp
stringE (Name -> String -> String
parenInfixConName Name
conName " "))
                                    [| (<>) |]
                                    Q Exp
mappendArgs

         PatQ -> BodyQ -> [Q Dec] -> MatchQ
match (Name -> [PatQ] -> PatQ
conP Name
conName ([PatQ] -> PatQ) -> [PatQ] -> PatQ
forall a b. (a -> b) -> a -> b
$ (Name -> PatQ) -> [Name] -> [PatQ]
forall a b. (a -> b) -> [a] -> [b]
map Name -> PatQ
varP [Name]
args)
               (Q Exp -> BodyQ
normalB (Q Exp -> BodyQ) -> Q Exp -> BodyQ
forall a b. (a -> b) -> a -> b
$ Name -> Q Exp
varE (TextShowFun -> Name
showParenName TextShowFun
tsFun)
                            Q Exp -> Q Exp -> Q Exp
`appE` Q Exp -> Q Exp -> Q Exp -> Q Exp
infixApp (Name -> Q Exp
varE Name
p) [| (>) |] (Int -> Q Exp
integerE Int
appPrec)
                            Q Exp -> Q Exp -> Q Exp
`appE` Q Exp
namedArgs)
               []
makeTextShowForCon p :: Name
p tsClass :: TextShowClass
tsClass tsFun :: TextShowFun
tsFun tvMap :: Map Name (Name, Name)
tvMap
  (ConstructorInfo { constructorName :: ConstructorInfo -> Name
constructorName    = Name
conName
                   , constructorVariant :: ConstructorInfo -> ConstructorVariant
constructorVariant = RecordConstructor argNames :: [Name]
argNames
                   , constructorFields :: ConstructorInfo -> Cxt
constructorFields  = Cxt
argTys }) = do
    Cxt
argTys' <- (Type -> TypeQ) -> Cxt -> CxtQ
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
mapM Type -> TypeQ
resolveTypeSynonyms Cxt
argTys
    [Name]
args <- String -> Int -> Q [Name]
newNameList "arg" (Int -> Q [Name]) -> Int -> Q [Name]
forall a b. (a -> b) -> a -> b
$ Cxt -> Int
forall (t :: * -> *) a. Foldable t => t a -> Int
length Cxt
argTys'

    let showArgs :: [Q Exp]
showArgs       = ((Name, Type, Name) -> [Q Exp]) -> [(Name, Type, Name)] -> [Q Exp]
forall (t :: * -> *) a b. Foldable t => (a -> [b]) -> t a -> [b]
concatMap (\(argName :: Name
argName, argTy :: Type
argTy, arg :: Name
arg)
                                      -> let argNameBase :: String
argNameBase = Name -> String
nameBase Name
argName
                                             infixRec :: String
infixRec    = Bool -> (String -> String) -> String -> String
showParen (String -> Bool
isSymVar String
argNameBase)
                                                                     (String -> String -> String
showString String
argNameBase) ""
                                         in [ Name -> Q Exp
varE (TextShowFun -> Name
fromStringName TextShowFun
tsFun) Q Exp -> Q Exp -> Q Exp
`appE` String -> Q Exp
stringE (String
infixRec String -> String -> String
forall a. [a] -> [a] -> [a]
++ " = ")
                                            , Int
-> TextShowClass
-> TextShowFun
-> Name
-> Map Name (Name, Name)
-> Type
-> Name
-> Q Exp
makeTextShowForArg 0 TextShowClass
tsClass TextShowFun
tsFun Name
conName Map Name (Name, Name)
tvMap Type
argTy Name
arg
                                            , Name -> Q Exp
varE (TextShowFun -> Name
showCommaSpaceName TextShowFun
tsFun)
                                            ]
                                   )
                                   ([Name] -> Cxt -> [Name] -> [(Name, Type, Name)]
forall a b c. [a] -> [b] -> [c] -> [(a, b, c)]
zip3 [Name]
argNames Cxt
argTys' [Name]
args)
        braceCommaArgs :: [Q Exp]
braceCommaArgs = (Name -> Q Exp
varE (TextShowFun -> Name
singletonName TextShowFun
tsFun) Q Exp -> Q Exp -> Q Exp
`appE` Char -> Q Exp
charE '{') Q Exp -> [Q Exp] -> [Q Exp]
forall a. a -> [a] -> [a]
: Int -> [Q Exp] -> [Q Exp]
forall a. Int -> [a] -> [a]
take ([Q Exp] -> Int
forall (t :: * -> *) a. Foldable t => t a -> Int
length [Q Exp]
showArgs Int -> Int -> Int
forall a. Num a => a -> a -> a
- 1) [Q Exp]
showArgs
        mappendArgs :: Q Exp
mappendArgs    = (Q Exp -> Q Exp -> Q Exp) -> Q Exp -> [Q Exp] -> Q Exp
forall (t :: * -> *) a b.
Foldable t =>
(a -> b -> b) -> b -> t a -> b
foldr' (Q Exp -> Q Exp -> Q Exp -> Q Exp
`infixApp` [| (<>) |])
                                (Name -> Q Exp
varE (TextShowFun -> Name
singletonName TextShowFun
tsFun) Q Exp -> Q Exp -> Q Exp
`appE` Char -> Q Exp
charE '}')
                                [Q Exp]
braceCommaArgs
        namedArgs :: Q Exp
namedArgs      = Q Exp -> Q Exp -> Q Exp -> Q Exp
infixApp (Name -> Q Exp
varE (TextShowFun -> Name
fromStringName TextShowFun
tsFun) Q Exp -> Q Exp -> Q Exp
`appE` String -> Q Exp
stringE (Name -> String -> String
parenInfixConName Name
conName " "))
                                  [| (<>) |]
                                  Q Exp
mappendArgs

    PatQ -> BodyQ -> [Q Dec] -> MatchQ
match
      (Name -> [PatQ] -> PatQ
conP Name
conName ([PatQ] -> PatQ) -> [PatQ] -> PatQ
forall a b. (a -> b) -> a -> b
$ (Name -> PatQ) -> [Name] -> [PatQ]
forall a b. (a -> b) -> [a] -> [b]
map Name -> PatQ
varP [Name]
args)
      (Q Exp -> BodyQ
normalB (Q Exp -> BodyQ) -> Q Exp -> BodyQ
forall a b. (a -> b) -> a -> b
$ Name -> Q Exp
varE (TextShowFun -> Name
showParenName TextShowFun
tsFun)
                  Q Exp -> Q Exp -> Q Exp
`appE` Q Exp -> Q Exp -> Q Exp -> Q Exp
infixApp (Name -> Q Exp
varE Name
p) [| (>) |] (Int -> Q Exp
integerE Int
appPrec)
                  Q Exp -> Q Exp -> Q Exp
`appE` Q Exp
namedArgs)
      []
makeTextShowForCon p :: Name
p tsClass :: TextShowClass
tsClass tsFun :: TextShowFun
tsFun tvMap :: Map Name (Name, Name)
tvMap
  (ConstructorInfo { constructorName :: ConstructorInfo -> Name
constructorName    = Name
conName
                   , constructorVariant :: ConstructorInfo -> ConstructorVariant
constructorVariant = ConstructorVariant
InfixConstructor
                   , constructorFields :: ConstructorInfo -> Cxt
constructorFields  = Cxt
argTys }) = do
    [alTy :: Type
alTy, arTy :: Type
arTy] <- (Type -> TypeQ) -> Cxt -> CxtQ
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
mapM Type -> TypeQ
resolveTypeSynonyms Cxt
argTys
    Name
al <- String -> Q Name
newName "argL"
    Name
ar <- String -> Q Name
newName "argR"
    Fixity
fi <- Fixity -> Maybe Fixity -> Fixity
forall a. a -> Maybe a -> a
fromMaybe Fixity
defaultFixity (Maybe Fixity -> Fixity) -> Q (Maybe Fixity) -> Q Fixity
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> Name -> Q (Maybe Fixity)
reifyFixityCompat Name
conName
    let conPrec :: Int
conPrec  = case Fixity
fi of Fixity prec :: Int
prec _ -> Int
prec
        opName :: String
opName   = Name -> String
nameBase Name
conName
        infixOpE :: Q Exp
infixOpE = Q Exp -> Q Exp -> Q Exp
appE (Name -> Q Exp
varE (Name -> Q Exp) -> Name -> Q Exp
forall a b. (a -> b) -> a -> b
$ TextShowFun -> Name
fromStringName TextShowFun
tsFun) (Q Exp -> Q Exp) -> (String -> Q Exp) -> String -> Q Exp
forall b c a. (b -> c) -> (a -> b) -> a -> c
. String -> Q Exp
stringE (String -> Q Exp) -> String -> Q Exp
forall a b. (a -> b) -> a -> b
$
                     if String -> Bool
isInfixDataCon String
opName
                        then " "  String -> String -> String
forall a. [a] -> [a] -> [a]
++ String
opName String -> String -> String
forall a. [a] -> [a] -> [a]
++ " "
                        else " `" String -> String -> String
forall a. [a] -> [a] -> [a]
++ String
opName String -> String -> String
forall a. [a] -> [a] -> [a]
++ "` "

    PatQ -> BodyQ -> [Q Dec] -> MatchQ
match
      (PatQ -> Name -> PatQ -> PatQ
infixP (Name -> PatQ
varP Name
al) Name
conName (Name -> PatQ
varP Name
ar))
      (Q Exp -> BodyQ
normalB (Q Exp -> BodyQ) -> Q Exp -> BodyQ
forall a b. (a -> b) -> a -> b
$ (Name -> Q Exp
varE (TextShowFun -> Name
showParenName TextShowFun
tsFun) Q Exp -> Q Exp -> Q Exp
`appE` Q Exp -> Q Exp -> Q Exp -> Q Exp
infixApp (Name -> Q Exp
varE Name
p) [| (>) |] (Int -> Q Exp
integerE Int
conPrec))
                   Q Exp -> Q Exp -> Q Exp
`appE` (Q Exp -> Q Exp -> Q Exp -> Q Exp
infixApp (Int
-> TextShowClass
-> TextShowFun
-> Name
-> Map Name (Name, Name)
-> Type
-> Name
-> Q Exp
makeTextShowForArg (Int
conPrec Int -> Int -> Int
forall a. Num a => a -> a -> a
+ 1) TextShowClass
tsClass TextShowFun
tsFun Name
conName Map Name (Name, Name)
tvMap Type
alTy Name
al)
                                    [| (<>) |]
                                    (Q Exp -> Q Exp -> Q Exp -> Q Exp
infixApp Q Exp
infixOpE
                                              [| (<>) |]
                                              (Int
-> TextShowClass
-> TextShowFun
-> Name
-> Map Name (Name, Name)
-> Type
-> Name
-> Q Exp
makeTextShowForArg (Int
conPrec Int -> Int -> Int
forall a. Num a => a -> a -> a
+ 1) TextShowClass
tsClass TextShowFun
tsFun Name
conName Map Name (Name, Name)
tvMap Type
arTy Name
ar)))
      )
      []

-- | Generates a lambda expression for howbPrec/liftShowbPrec/etc. for an
-- argument of a constructor.
makeTextShowForArg :: Int
                   -> TextShowClass
                   -> TextShowFun
                   -> Name
                   -> TyVarMap
                   -> Type
                   -> Name
                   -> Q Exp
makeTextShowForArg :: Int
-> TextShowClass
-> TextShowFun
-> Name
-> Map Name (Name, Name)
-> Type
-> Name
-> Q Exp
makeTextShowForArg p :: Int
p _ tsFun :: TextShowFun
tsFun _ _ (ConT tyName :: Name
tyName) tyExpName :: Name
tyExpName =
    Q Exp
showE
  where
    tyVarE, showPrecE :: Q Exp
    tyVarE :: Q Exp
tyVarE    = Name -> Q Exp
varE Name
tyExpName
    showPrecE :: Q Exp
showPrecE = Name -> Q Exp
varE (TextShowClass -> TextShowFun -> Name
showPrecName TextShowClass
TextShow TextShowFun
tsFun)

    showE :: Q Exp
    showE :: Q Exp
showE =
      case Name -> Map Name PrimShow -> Maybe PrimShow
forall k a. Ord k => k -> Map k a -> Maybe a
Map.lookup Name
tyName Map Name PrimShow
primShowTbl of
        Just ps :: PrimShow
ps -> PrimShow -> Q Exp
showPrimE PrimShow
ps
        Nothing -> Q Exp
showPrecE Q Exp -> Q Exp -> Q Exp
`appE` Int -> Q Exp
integerE Int
p Q Exp -> Q Exp -> Q Exp
`appE` Q Exp
tyVarE

    showPrimE :: PrimShow -> Q Exp
    showPrimE :: PrimShow -> Q Exp
showPrimE PrimShow{ Q Exp -> Q Exp
primShowBoxer :: PrimShow -> Q Exp -> Q Exp
primShowBoxer :: Q Exp -> Q Exp
primShowBoxer
#if __GLASGOW_HASKELL__ >= 800
                      , TextShowFun -> Q Exp
primShowPostfixMod :: PrimShow -> TextShowFun -> Q Exp
primShowPostfixMod :: TextShowFun -> Q Exp
primShowPostfixMod, TextShowFun -> Q Exp -> Q Exp
primShowConv :: PrimShow -> TextShowFun -> Q Exp -> Q Exp
primShowConv :: TextShowFun -> Q Exp -> Q Exp
primShowConv
#endif
                      }
#if __GLASGOW_HASKELL__ >= 800
        -- Starting with GHC 8.0, data types containing unlifted types with
        -- derived Show instances show hashed literals with actual hash signs,
        -- and negative hashed literals are not surrounded with parentheses.
      = TextShowFun -> Q Exp -> Q Exp
primShowConv TextShowFun
tsFun (Q Exp -> Q Exp) -> Q Exp -> Q Exp
forall a b. (a -> b) -> a -> b
$ Q Exp -> Q Exp -> Q Exp -> Q Exp
infixApp (Int -> Q Exp
primE 0) [| (<>) |] (TextShowFun -> Q Exp
primShowPostfixMod TextShowFun
tsFun)
#else
      = primE p
#endif
      where
        primE :: Int -> Q Exp
        primE :: Int -> Q Exp
primE prec :: Int
prec = Q Exp
showPrecE Q Exp -> Q Exp -> Q Exp
`appE` Int -> Q Exp
integerE Int
prec Q Exp -> Q Exp -> Q Exp
`appE` Q Exp -> Q Exp
primShowBoxer Q Exp
tyVarE

makeTextShowForArg p :: Int
p tsClass :: TextShowClass
tsClass tsFun :: TextShowFun
tsFun conName :: Name
conName tvMap :: Map Name (Name, Name)
tvMap ty :: Type
ty tyExpName :: Name
tyExpName =
    [| $(makeTextShowForType tsClass tsFun conName tvMap False ty) p $(varE tyExpName) |]

-- | Generates a lambda expression for howbPrec/liftShowbPrec/etc. for a
-- specific type. The generated expression depends on the number of type variables.
--
-- 1. If the type is of kind * (T), apply showbPrec.
-- 2. If the type is of kind * -> * (T a), apply liftShowbPrec $(makeTextShowForType a)
-- 3. If the type is of kind * -> * -> * (T a b), apply
--    liftShowbPrec2 $(makeTextShowForType a) $(makeTextShowForType b)
makeTextShowForType :: TextShowClass
                    -> TextShowFun
                    -> Name
                    -> TyVarMap
                    -> Bool -- ^ True if we are using the function of type ([a] -> Builder),
                            --   False if we are using the function of type (Int -> a -> Builder).
                    -> Type
                    -> Q Exp
makeTextShowForType :: TextShowClass
-> TextShowFun
-> Name
-> Map Name (Name, Name)
-> Bool
-> Type
-> Q Exp
makeTextShowForType _ tsFun :: TextShowFun
tsFun _ tvMap :: Map Name (Name, Name)
tvMap sl :: Bool
sl (VarT tyName :: Name
tyName) =
    Name -> Q Exp
varE (Name -> Q Exp) -> Name -> Q Exp
forall a b. (a -> b) -> a -> b
$ case Name -> Map Name (Name, Name) -> Maybe (Name, Name)
forall k a. Ord k => k -> Map k a -> Maybe a
Map.lookup Name
tyName Map Name (Name, Name)
tvMap of
         Just (spExp :: Name
spExp, slExp :: Name
slExp) -> if Bool
sl then Name
slExp else Name
spExp
         Nothing             -> if Bool
sl then TextShowClass -> TextShowFun -> Name
showListName TextShowClass
TextShow TextShowFun
tsFun
                                      else TextShowClass -> TextShowFun -> Name
showPrecName TextShowClass
TextShow TextShowFun
tsFun
makeTextShowForType tsClass :: TextShowClass
tsClass tsFun :: TextShowFun
tsFun conName :: Name
conName tvMap :: Map Name (Name, Name)
tvMap sl :: Bool
sl (SigT ty :: Type
ty _) =
    TextShowClass
-> TextShowFun
-> Name
-> Map Name (Name, Name)
-> Bool
-> Type
-> Q Exp
makeTextShowForType TextShowClass
tsClass TextShowFun
tsFun Name
conName Map Name (Name, Name)
tvMap Bool
sl Type
ty
makeTextShowForType tsClass :: TextShowClass
tsClass tsFun :: TextShowFun
tsFun conName :: Name
conName tvMap :: Map Name (Name, Name)
tvMap sl :: Bool
sl (ForallT _ _ ty :: Type
ty) =
    TextShowClass
-> TextShowFun
-> Name
-> Map Name (Name, Name)
-> Bool
-> Type
-> Q Exp
makeTextShowForType TextShowClass
tsClass TextShowFun
tsFun Name
conName Map Name (Name, Name)
tvMap Bool
sl Type
ty
makeTextShowForType tsClass :: TextShowClass
tsClass tsFun :: TextShowFun
tsFun conName :: Name
conName tvMap :: Map Name (Name, Name)
tvMap sl :: Bool
sl ty :: Type
ty = do
    let tyCon :: Type
        tyArgs :: [Type]
        tyCon :: Type
tyCon :| tyArgs :: Cxt
tyArgs = Type -> NonEmpty Type
unapplyTy Type
ty

        numLastArgs :: Int
        numLastArgs :: Int
numLastArgs = Int -> Int -> Int
forall a. Ord a => a -> a -> a
min (TextShowClass -> Int
forall a. Enum a => a -> Int
fromEnum TextShowClass
tsClass) (Cxt -> Int
forall (t :: * -> *) a. Foldable t => t a -> Int
length Cxt
tyArgs)

        lhsArgs, rhsArgs :: [Type]
        (lhsArgs :: Cxt
lhsArgs, rhsArgs :: Cxt
rhsArgs) = Int -> Cxt -> (Cxt, Cxt)
forall a. Int -> [a] -> ([a], [a])
splitAt (Cxt -> Int
forall (t :: * -> *) a. Foldable t => t a -> Int
length Cxt
tyArgs Int -> Int -> Int
forall a. Num a => a -> a -> a
- Int
numLastArgs) Cxt
tyArgs

        tyVarNames :: [Name]
        tyVarNames :: [Name]
tyVarNames = Map Name (Name, Name) -> [Name]
forall k a. Map k a -> [k]
Map.keys Map Name (Name, Name)
tvMap

    Bool
itf <- Type -> Q Bool
isTyFamily Type
tyCon
    if (Type -> Bool) -> Cxt -> Bool
forall (t :: * -> *) a. Foldable t => (a -> Bool) -> t a -> Bool
any (Type -> [Name] -> Bool
`mentionsName` [Name]
tyVarNames) Cxt
lhsArgs
          Bool -> Bool -> Bool
|| Bool
itf Bool -> Bool -> Bool
&& (Type -> Bool) -> Cxt -> Bool
forall (t :: * -> *) a. Foldable t => (a -> Bool) -> t a -> Bool
any (Type -> [Name] -> Bool
`mentionsName` [Name]
tyVarNames) Cxt
tyArgs
       then TextShowClass -> Name -> Q Exp
forall a. TextShowClass -> Name -> a
outOfPlaceTyVarError TextShowClass
tsClass Name
conName
       else if (Type -> Bool) -> Cxt -> Bool
forall (t :: * -> *) a. Foldable t => (a -> Bool) -> t a -> Bool
any (Type -> [Name] -> Bool
`mentionsName` [Name]
tyVarNames) Cxt
rhsArgs
               then [Q Exp] -> Q Exp
appsE ([Q Exp] -> Q Exp) -> [Q Exp] -> Q Exp
forall a b. (a -> b) -> a -> b
$ [ Name -> Q Exp
varE (Name -> Q Exp) -> Name -> Q Exp
forall a b. (a -> b) -> a -> b
$ Bool -> TextShowClass -> TextShowFun -> Name
showPrecOrListName Bool
sl (Int -> TextShowClass
forall a. Enum a => Int -> a
toEnum Int
numLastArgs) TextShowFun
tsFun]
                            [Q Exp] -> [Q Exp] -> [Q Exp]
forall a. [a] -> [a] -> [a]
++ (Bool -> Type -> Q Exp) -> [Bool] -> Cxt -> [Q Exp]
forall a b c. (a -> b -> c) -> [a] -> [b] -> [c]
zipWith (TextShowClass
-> TextShowFun
-> Name
-> Map Name (Name, Name)
-> Bool
-> Type
-> Q Exp
makeTextShowForType TextShowClass
tsClass TextShowFun
tsFun Name
conName Map Name (Name, Name)
tvMap)
                                       ([Bool] -> [Bool]
forall a. [a] -> [a]
cycle [Bool
False,Bool
True])
                                       (Cxt -> Cxt -> Cxt
forall a. [a] -> [a] -> [a]
interleave Cxt
rhsArgs Cxt
rhsArgs)
               else Name -> Q Exp
varE (Name -> Q Exp) -> Name -> Q Exp
forall a b. (a -> b) -> a -> b
$ if Bool
sl then TextShowClass -> TextShowFun -> Name
showListName TextShowClass
TextShow TextShowFun
tsFun
                                 else TextShowClass -> TextShowFun -> Name
showPrecName TextShowClass
TextShow TextShowFun
tsFun

-------------------------------------------------------------------------------
-- Template Haskell reifying and AST manipulation
-------------------------------------------------------------------------------

-- For the given Types, generate an instance context and head. Coming up with
-- the instance type isn't as simple as dropping the last types, as you need to
-- be wary of kinds being instantiated with *.
-- See Note [Type inference in derived instances]
buildTypeInstance :: TextShowClass
                  -- ^ TextShow, TextShow1, or TextShow2
                  -> Name
                  -- ^ The type constructor or data family name
                  -> Cxt
                  -- ^ The datatype context
                  -> [Type]
                  -- ^ The types to instantiate the instance with
                  -> DatatypeVariant
                  -- ^ Are we dealing with a data family instance or not
                  -> Q (Cxt, Type)
buildTypeInstance :: TextShowClass
-> Name -> Cxt -> Cxt -> DatatypeVariant -> Q (Cxt, Type)
buildTypeInstance tsClass :: TextShowClass
tsClass tyConName :: Name
tyConName dataCxt :: Cxt
dataCxt varTysOrig :: Cxt
varTysOrig variant :: DatatypeVariant
variant = do
    -- Make sure to expand through type/kind synonyms! Otherwise, the
    -- eta-reduction check might get tripped up over type variables in a
    -- synonym that are actually dropped.
    -- (See GHC Trac #11416 for a scenario where this actually happened.)
    Cxt
varTysExp <- (Type -> TypeQ) -> Cxt -> CxtQ
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
mapM Type -> TypeQ
resolveTypeSynonyms Cxt
varTysOrig

    let remainingLength :: Int
        remainingLength :: Int
remainingLength = Cxt -> Int
forall (t :: * -> *) a. Foldable t => t a -> Int
length Cxt
varTysOrig Int -> Int -> Int
forall a. Num a => a -> a -> a
- TextShowClass -> Int
forall a. Enum a => a -> Int
fromEnum TextShowClass
tsClass

        droppedTysExp :: [Type]
        droppedTysExp :: Cxt
droppedTysExp = Int -> Cxt -> Cxt
forall a. Int -> [a] -> [a]
drop Int
remainingLength Cxt
varTysExp

        droppedStarKindStati :: [StarKindStatus]
        droppedStarKindStati :: [StarKindStatus]
droppedStarKindStati = (Type -> StarKindStatus) -> Cxt -> [StarKindStatus]
forall a b. (a -> b) -> [a] -> [b]
map Type -> StarKindStatus
canRealizeKindStar Cxt
droppedTysExp

    -- Check there are enough types to drop and that all of them are either of
    -- kind * or kind k (for some kind variable k). If not, throw an error.
    Bool -> Q () -> Q ()
forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
when (Int
remainingLength Int -> Int -> Bool
forall a. Ord a => a -> a -> Bool
< 0 Bool -> Bool -> Bool
|| (StarKindStatus -> Bool) -> [StarKindStatus] -> Bool
forall (t :: * -> *) a. Foldable t => (a -> Bool) -> t a -> Bool
any (StarKindStatus -> StarKindStatus -> Bool
forall a. Eq a => a -> a -> Bool
== StarKindStatus
NotKindStar) [StarKindStatus]
droppedStarKindStati) (Q () -> Q ()) -> Q () -> Q ()
forall a b. (a -> b) -> a -> b
$
      TextShowClass -> Name -> Q ()
forall a. TextShowClass -> Name -> a
derivingKindError TextShowClass
tsClass Name
tyConName

    let droppedKindVarNames :: [Name]
        droppedKindVarNames :: [Name]
droppedKindVarNames = [StarKindStatus] -> [Name]
catKindVarNames [StarKindStatus]
droppedStarKindStati

        -- Substitute kind * for any dropped kind variables
        varTysExpSubst :: [Type]
        varTysExpSubst :: Cxt
varTysExpSubst = (Type -> Type) -> Cxt -> Cxt
forall a b. (a -> b) -> [a] -> [b]
map ([Name] -> Type -> Type
substNamesWithKindStar [Name]
droppedKindVarNames) Cxt
varTysExp

        remainingTysExpSubst, droppedTysExpSubst :: [Type]
        (remainingTysExpSubst :: Cxt
remainingTysExpSubst, droppedTysExpSubst :: Cxt
droppedTysExpSubst) =
          Int -> Cxt -> (Cxt, Cxt)
forall a. Int -> [a] -> ([a], [a])
splitAt Int
remainingLength Cxt
varTysExpSubst

        -- All of the type variables mentioned in the dropped types
        -- (post-synonym expansion)
        droppedTyVarNames :: [Name]
        droppedTyVarNames :: [Name]
droppedTyVarNames = Cxt -> [Name]
forall a. TypeSubstitution a => a -> [Name]
freeVariables Cxt
droppedTysExpSubst

    -- If any of the dropped types were polykinded, ensure that they are of kind *
    -- after substituting * for the dropped kind variables. If not, throw an error.
    Bool -> Q () -> Q ()
forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
unless ((Type -> Bool) -> Cxt -> Bool
forall (t :: * -> *) a. Foldable t => (a -> Bool) -> t a -> Bool
all Type -> Bool
hasKindStar Cxt
droppedTysExpSubst) (Q () -> Q ()) -> Q () -> Q ()
forall a b. (a -> b) -> a -> b
$
      TextShowClass -> Name -> Q ()
forall a. TextShowClass -> Name -> a
derivingKindError TextShowClass
tsClass Name
tyConName

    let preds    :: [Maybe Pred]
        kvNames  :: [[Name]]
        kvNames' :: [Name]
        -- Derive instance constraints (and any kind variables which are specialized
        -- to * in those constraints)
        (preds :: [Maybe Type]
preds, kvNames :: [[Name]]
kvNames) = [(Maybe Type, [Name])] -> ([Maybe Type], [[Name]])
forall a b. [(a, b)] -> ([a], [b])
unzip ([(Maybe Type, [Name])] -> ([Maybe Type], [[Name]]))
-> [(Maybe Type, [Name])] -> ([Maybe Type], [[Name]])
forall a b. (a -> b) -> a -> b
$ (Type -> (Maybe Type, [Name])) -> Cxt -> [(Maybe Type, [Name])]
forall a b. (a -> b) -> [a] -> [b]
map (TextShowClass -> Type -> (Maybe Type, [Name])
deriveConstraint TextShowClass
tsClass) Cxt
remainingTysExpSubst
        kvNames' :: [Name]
kvNames' = [[Name]] -> [Name]
forall (t :: * -> *) a. Foldable t => t [a] -> [a]
concat [[Name]]
kvNames

        -- Substitute the kind variables specialized in the constraints with *
        remainingTysExpSubst' :: [Type]
        remainingTysExpSubst' :: Cxt
remainingTysExpSubst' =
          (Type -> Type) -> Cxt -> Cxt
forall a b. (a -> b) -> [a] -> [b]
map ([Name] -> Type -> Type
substNamesWithKindStar [Name]
kvNames') Cxt
remainingTysExpSubst

        -- We now substitute all of the specialized-to-* kind variable names with
        -- *, but in the original types, not the synonym-expanded types. The reason
        -- we do this is a superficial one: we want the derived instance to resemble
        -- the datatype written in source code as closely as possible. For example,
        -- for the following data family instance:
        --
        --   data family Fam a
        --   newtype instance Fam String = Fam String
        --
        -- We'd want to generate the instance:
        --
        --   instance C (Fam String)
        --
        -- Not:
        --
        --   instance C (Fam [Char])
        remainingTysOrigSubst :: [Type]
        remainingTysOrigSubst :: Cxt
remainingTysOrigSubst =
          (Type -> Type) -> Cxt -> Cxt
forall a b. (a -> b) -> [a] -> [b]
map ([Name] -> Type -> Type
substNamesWithKindStar ([Name] -> [Name] -> [Name]
forall a. Eq a => [a] -> [a] -> [a]
union [Name]
droppedKindVarNames [Name]
kvNames'))
            (Cxt -> Cxt) -> Cxt -> Cxt
forall a b. (a -> b) -> a -> b
$ Int -> Cxt -> Cxt
forall a. Int -> [a] -> [a]
take Int
remainingLength Cxt
varTysOrig

        isDataFamily :: Bool
        isDataFamily :: Bool
isDataFamily = case DatatypeVariant
variant of
                         Datatype        -> Bool
False
                         Newtype         -> Bool
False
                         DataInstance    -> Bool
True
                         NewtypeInstance -> Bool
True

        remainingTysOrigSubst' :: [Type]
        -- See Note [Kind signatures in derived instances] for an explanation
        -- of the isDataFamily check.
        remainingTysOrigSubst' :: Cxt
remainingTysOrigSubst' =
          if Bool
isDataFamily
             then Cxt
remainingTysOrigSubst
             else (Type -> Type) -> Cxt -> Cxt
forall a b. (a -> b) -> [a] -> [b]
map Type -> Type
unSigT Cxt
remainingTysOrigSubst

        instanceCxt :: Cxt
        instanceCxt :: Cxt
instanceCxt = [Maybe Type] -> Cxt
forall a. [Maybe a] -> [a]
catMaybes [Maybe Type]
preds

        instanceType :: Type
        instanceType :: Type
instanceType = Type -> Type -> Type
AppT (Name -> Type
ConT (Name -> Type) -> Name -> Type
forall a b. (a -> b) -> a -> b
$ TextShowClass -> Name
textShowClassName TextShowClass
tsClass)
                     (Type -> Type) -> Type -> Type
forall a b. (a -> b) -> a -> b
$ Name -> Cxt -> Type
applyTyCon Name
tyConName Cxt
remainingTysOrigSubst'

    -- If the datatype context mentions any of the dropped type variables,
    -- we can't derive an instance, so throw an error.
    Bool -> Q () -> Q ()
forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
when ((Type -> Bool) -> Cxt -> Bool
forall (t :: * -> *) a. Foldable t => (a -> Bool) -> t a -> Bool
any (Type -> [Name] -> Bool
`predMentionsName` [Name]
droppedTyVarNames) Cxt
dataCxt) (Q () -> Q ()) -> Q () -> Q ()
forall a b. (a -> b) -> a -> b
$
      Name -> Type -> Q ()
forall a. Name -> Type -> a
datatypeContextError Name
tyConName Type
instanceType
    -- Also ensure the dropped types can be safely eta-reduced. Otherwise,
    -- throw an error.
    Bool -> Q () -> Q ()
forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
unless (Cxt -> Cxt -> Bool
canEtaReduce Cxt
remainingTysExpSubst' Cxt
droppedTysExpSubst) (Q () -> Q ()) -> Q () -> Q ()
forall a b. (a -> b) -> a -> b
$
      Type -> Q ()
forall a. Type -> a
etaReductionError Type
instanceType
    (Cxt, Type) -> Q (Cxt, Type)
forall (m :: * -> *) a. Monad m => a -> m a
return (Cxt
instanceCxt, Type
instanceType)

-- | Attempt to derive a constraint on a Type. If successful, return
-- Just the constraint and any kind variable names constrained to *.
-- Otherwise, return Nothing and the empty list.
--
-- See Note [Type inference in derived instances] for the heuristics used to
-- come up with constraints.
deriveConstraint :: TextShowClass -> Type -> (Maybe Pred, [Name])
deriveConstraint :: TextShowClass -> Type -> (Maybe Type, [Name])
deriveConstraint tsClass :: TextShowClass
tsClass t :: Type
t
  | Bool -> Bool
not (Type -> Bool
isTyVar Type
t) = (Maybe Type
forall a. Maybe a
Nothing, [])
  | Type -> Bool
hasKindStar Type
t   = (Type -> Maybe Type
forall a. a -> Maybe a
Just (Name -> Name -> Type
applyClass ''TextShow Name
tName), [])
  | Bool
otherwise = case Int -> Type -> Maybe [Name]
hasKindVarChain 1 Type
t of
      Just ns :: [Name]
ns | TextShowClass
tsClass TextShowClass -> TextShowClass -> Bool
forall a. Ord a => a -> a -> Bool
>= TextShowClass
TextShow1
              -> (Type -> Maybe Type
forall a. a -> Maybe a
Just (Name -> Name -> Type
applyClass ''TextShow1 Name
tName), [Name]
ns)
      _ -> case Int -> Type -> Maybe [Name]
hasKindVarChain 2 Type
t of
           Just ns :: [Name]
ns | TextShowClass
tsClass TextShowClass -> TextShowClass -> Bool
forall a. Eq a => a -> a -> Bool
== TextShowClass
TextShow2
                   -> (Type -> Maybe Type
forall a. a -> Maybe a
Just (Name -> Name -> Type
applyClass ''TextShow2 Name
tName), [Name]
ns)
           _ -> (Maybe Type
forall a. Maybe a
Nothing, [])
  where
    tName :: Name
    tName :: Name
tName = Type -> Name
varTToName Type
t

{-
Note [Kind signatures in derived instances]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

It is possible to put explicit kind signatures into the derived instances, e.g.,

  instance C a => C (Data (f :: * -> *)) where ...

But it is preferable to avoid this if possible. If we come up with an incorrect
kind signature (which is entirely possible, since our type inferencer is pretty
unsophisticated - see Note [Type inference in derived instances]), then GHC will
flat-out reject the instance, which is quite unfortunate.

Plain old datatypes have the advantage that you can avoid using any kind signatures
at all in their instances. This is because a datatype declaration uses all type
variables, so the types that we use in a derived instance uniquely determine their
kinds. As long as we plug in the right types, the kind inferencer can do the rest
of the work. For this reason, we use unSigT to remove all kind signatures before
splicing in the instance context and head.

Data family instances are trickier, since a data family can have two instances that
are distinguished by kind alone, e.g.,

  data family Fam (a :: k)
  data instance Fam (a :: * -> *)
  data instance Fam (a :: *)

If we dropped the kind signatures for C (Fam a), then GHC will have no way of
knowing which instance we are talking about. To avoid this scenario, we always
include explicit kind signatures in data family instances. There is a chance that
the inferred kind signatures will be incorrect, but if so, we can always fall back
on the make- functions.

Note [Type inference in derived instances]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Type inference is can be tricky to get right, and we want to avoid recreating the
entirety of GHC's type inferencer in Template Haskell. For this reason, we will
probably never come up with derived instance contexts that are as accurate as
GHC's. But that doesn't mean we can't do anything! There are a couple of simple
things we can do to make instance contexts that work for 80% of use cases:

1. If one of the last type parameters is polykinded, then its kind will be
   specialized to * in the derived instance. We note what kind variable the type
   parameter had and substitute it with * in the other types as well. For example,
   imagine you had

     data Data (a :: k) (b :: k)

   Then you'd want to derived instance to be:

     instance C (Data (a :: *))

   Not:

     instance C (Data (a :: k))

2. We naïvely come up with instance constraints using the following criteria:

   (i)   If there's a type parameter n of kind *, generate a TextShow n constraint.
   (ii)  If there's a type parameter n of kind k1 -> k2 (where k1/k2 are * or kind
         variables), then generate a TextShow1 n constraint, and if k1/k2 are kind
         variables, then substitute k1/k2 with * elsewhere in the types. We must
         consider the case where they are kind variables because you might have a
         scenario like this:

           newtype Compose (f :: k2 -> *) (g :: k1 -> k2) (a :: k1)
             = Compose (f (g a))

         Which would have a derived TextShow1 instance of:

           instance (TextShow1 f, TextShow1 g) => TextShow1 (Compose f g) where ...
   (iii) If there's a type parameter n of kind k1 -> k2 -> k3 (where k1/k2/k3 are
         * or kind variables), then generate a TextShow2 constraint and perform
         kind substitution as in the other cases.
-}

-------------------------------------------------------------------------------
-- Error messages
-------------------------------------------------------------------------------

-- | Either the given data type doesn't have enough type variables, or one of
-- the type variables to be eta-reduced cannot realize kind *.
derivingKindError :: TextShowClass -> Name -> a
derivingKindError :: TextShowClass -> Name -> a
derivingKindError tsClass :: TextShowClass
tsClass tyConName :: Name
tyConName = String -> a
forall a. HasCallStack => String -> a
error
    (String -> a) -> (String -> String) -> String -> a
forall b c a. (b -> c) -> (a -> b) -> a -> c
. String -> String -> String
showString "Cannot derive well-kinded instance of form ‘"
    (String -> String) -> (String -> String) -> String -> String
forall b c a. (b -> c) -> (a -> b) -> a -> c
. String -> String -> String
showString String
className
    (String -> String) -> (String -> String) -> String -> String
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Char -> String -> String
showChar ' '
    (String -> String) -> (String -> String) -> String -> String
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Bool -> (String -> String) -> String -> String
showParen Bool
True
      ( String -> String -> String
showString (Name -> String
nameBase Name
tyConName)
      (String -> String) -> (String -> String) -> String -> String
forall b c a. (b -> c) -> (a -> b) -> a -> c
. String -> String -> String
showString " ..."
      )
    (String -> String) -> (String -> String) -> String -> String
forall b c a. (b -> c) -> (a -> b) -> a -> c
. String -> String -> String
showString "‘\n\tClass "
    (String -> String) -> (String -> String) -> String -> String
forall b c a. (b -> c) -> (a -> b) -> a -> c
. String -> String -> String
showString String
className
    (String -> String) -> (String -> String) -> String -> String
forall b c a. (b -> c) -> (a -> b) -> a -> c
. String -> String -> String
showString " expects an argument of kind "
    (String -> String) -> (String -> String) -> String -> String
forall b c a. (b -> c) -> (a -> b) -> a -> c
. String -> String -> String
showString (Type -> String
forall a. Ppr a => a -> String
pprint (Type -> String) -> (Int -> Type) -> Int -> String
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Int -> Type
createKindChain (Int -> String) -> Int -> String
forall a b. (a -> b) -> a -> b
$ TextShowClass -> Int
forall a. Enum a => a -> Int
fromEnum TextShowClass
tsClass)
    (String -> a) -> String -> a
forall a b. (a -> b) -> a -> b
$ ""
  where
    className :: String
    className :: String
className = Name -> String
nameBase (Name -> String) -> Name -> String
forall a b. (a -> b) -> a -> b
$ TextShowClass -> Name
textShowClassName TextShowClass
tsClass

-- | One of the last type variables cannot be eta-reduced (see the canEtaReduce
-- function for the criteria it would have to meet).
etaReductionError :: Type -> a
etaReductionError :: Type -> a
etaReductionError instanceType :: Type
instanceType = String -> a
forall a. HasCallStack => String -> a
error (String -> a) -> String -> a
forall a b. (a -> b) -> a -> b
$
    "Cannot eta-reduce to an instance of form \n\tinstance (...) => "
    String -> String -> String
forall a. [a] -> [a] -> [a]
++ Type -> String
forall a. Ppr a => a -> String
pprint Type
instanceType

-- | The data type has a DatatypeContext which mentions one of the eta-reduced
-- type variables.
datatypeContextError :: Name -> Type -> a
datatypeContextError :: Name -> Type -> a
datatypeContextError dataName :: Name
dataName instanceType :: Type
instanceType = String -> a
forall a. HasCallStack => String -> a
error
    (String -> a) -> (String -> String) -> String -> a
forall b c a. (b -> c) -> (a -> b) -> a -> c
. String -> String -> String
showString "Can't make a derived instance of ‘"
    (String -> String) -> (String -> String) -> String -> String
forall b c a. (b -> c) -> (a -> b) -> a -> c
. String -> String -> String
showString (Type -> String
forall a. Ppr a => a -> String
pprint Type
instanceType)
    (String -> String) -> (String -> String) -> String -> String
forall b c a. (b -> c) -> (a -> b) -> a -> c
. String -> String -> String
showString "‘:\n\tData type ‘"
    (String -> String) -> (String -> String) -> String -> String
forall b c a. (b -> c) -> (a -> b) -> a -> c
. String -> String -> String
showString (Name -> String
nameBase Name
dataName)
    (String -> String) -> (String -> String) -> String -> String
forall b c a. (b -> c) -> (a -> b) -> a -> c
. String -> String -> String
showString "‘ must not have a class context involving the last type argument(s)"
    (String -> a) -> String -> a
forall a b. (a -> b) -> a -> b
$ ""

-- | The data type mentions one of the n eta-reduced type variables in a place other
-- than the last nth positions of a data type in a constructor's field.
outOfPlaceTyVarError :: TextShowClass -> Name -> a
outOfPlaceTyVarError :: TextShowClass -> Name -> a
outOfPlaceTyVarError tsClass :: TextShowClass
tsClass conName :: Name
conName = String -> a
forall a. HasCallStack => String -> a
error
    (String -> a) -> (String -> String) -> String -> a
forall b c a. (b -> c) -> (a -> b) -> a -> c
. String -> String -> String
showString "Constructor ‘"
    (String -> String) -> (String -> String) -> String -> String
forall b c a. (b -> c) -> (a -> b) -> a -> c
. String -> String -> String
showString (Name -> String
nameBase Name
conName)
    (String -> String) -> (String -> String) -> String -> String
forall b c a. (b -> c) -> (a -> b) -> a -> c
. String -> String -> String
showString "‘ must only use its last "
    (String -> String) -> (String -> String) -> String -> String
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Int -> String -> String
forall a. Show a => a -> String -> String
shows Int
n
    (String -> String) -> (String -> String) -> String -> String
forall b c a. (b -> c) -> (a -> b) -> a -> c
. String -> String -> String
showString " type variable(s) within the last "
    (String -> String) -> (String -> String) -> String -> String
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Int -> String -> String
forall a. Show a => a -> String -> String
shows Int
n
    (String -> String) -> (String -> String) -> String -> String
forall b c a. (b -> c) -> (a -> b) -> a -> c
. String -> String -> String
showString " argument(s) of a data type"
    (String -> a) -> String -> a
forall a b. (a -> b) -> a -> b
$ ""
  where
    n :: Int
    n :: Int
n = TextShowClass -> Int
forall a. Enum a => a -> Int
fromEnum TextShowClass
tsClass

-------------------------------------------------------------------------------
-- Expanding type synonyms
-------------------------------------------------------------------------------

applySubstitutionKind :: Map Name Kind -> Type -> Type
#if MIN_VERSION_template_haskell(2,8,0)
applySubstitutionKind :: Map Name Type -> Type -> Type
applySubstitutionKind = Map Name Type -> Type -> Type
forall a. TypeSubstitution a => Map Name Type -> a -> a
applySubstitution
#else
applySubstitutionKind _ t = t
#endif

substNameWithKind :: Name -> Kind -> Type -> Type
substNameWithKind :: Name -> Type -> Type -> Type
substNameWithKind n :: Name
n k :: Type
k = Map Name Type -> Type -> Type
applySubstitutionKind (Name -> Type -> Map Name Type
forall k a. k -> a -> Map k a
Map.singleton Name
n Type
k)

substNamesWithKindStar :: [Name] -> Type -> Type
substNamesWithKindStar :: [Name] -> Type -> Type
substNamesWithKindStar ns :: [Name]
ns t :: Type
t = (Name -> Type -> Type) -> Type -> [Name] -> Type
forall (t :: * -> *) a b.
Foldable t =>
(a -> b -> b) -> b -> t a -> b
foldr' ((Name -> Type -> Type -> Type) -> Type -> Name -> Type -> Type
forall a b c. (a -> b -> c) -> b -> a -> c
flip Name -> Type -> Type -> Type
substNameWithKind Type
starK) Type
t [Name]
ns

-------------------------------------------------------------------------------
-- Class-specific constants
-------------------------------------------------------------------------------

-- | A representation of which TextShow variant is being derived.
data TextShowClass = TextShow | TextShow1 | TextShow2
  deriving (Int -> TextShowClass
TextShowClass -> Int
TextShowClass -> [TextShowClass]
TextShowClass -> TextShowClass
TextShowClass -> TextShowClass -> [TextShowClass]
TextShowClass -> TextShowClass -> TextShowClass -> [TextShowClass]
(TextShowClass -> TextShowClass)
-> (TextShowClass -> TextShowClass)
-> (Int -> TextShowClass)
-> (TextShowClass -> Int)
-> (TextShowClass -> [TextShowClass])
-> (TextShowClass -> TextShowClass -> [TextShowClass])
-> (TextShowClass -> TextShowClass -> [TextShowClass])
-> (TextShowClass
    -> TextShowClass -> TextShowClass -> [TextShowClass])
-> Enum TextShowClass
forall a.
(a -> a)
-> (a -> a)
-> (Int -> a)
-> (a -> Int)
-> (a -> [a])
-> (a -> a -> [a])
-> (a -> a -> [a])
-> (a -> a -> a -> [a])
-> Enum a
enumFromThenTo :: TextShowClass -> TextShowClass -> TextShowClass -> [TextShowClass]
$cenumFromThenTo :: TextShowClass -> TextShowClass -> TextShowClass -> [TextShowClass]
enumFromTo :: TextShowClass -> TextShowClass -> [TextShowClass]
$cenumFromTo :: TextShowClass -> TextShowClass -> [TextShowClass]
enumFromThen :: TextShowClass -> TextShowClass -> [TextShowClass]
$cenumFromThen :: TextShowClass -> TextShowClass -> [TextShowClass]
enumFrom :: TextShowClass -> [TextShowClass]
$cenumFrom :: TextShowClass -> [TextShowClass]
fromEnum :: TextShowClass -> Int
$cfromEnum :: TextShowClass -> Int
toEnum :: Int -> TextShowClass
$ctoEnum :: Int -> TextShowClass
pred :: TextShowClass -> TextShowClass
$cpred :: TextShowClass -> TextShowClass
succ :: TextShowClass -> TextShowClass
$csucc :: TextShowClass -> TextShowClass
Enum, TextShowClass -> TextShowClass -> Bool
(TextShowClass -> TextShowClass -> Bool)
-> (TextShowClass -> TextShowClass -> Bool) -> Eq TextShowClass
forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
/= :: TextShowClass -> TextShowClass -> Bool
$c/= :: TextShowClass -> TextShowClass -> Bool
== :: TextShowClass -> TextShowClass -> Bool
$c== :: TextShowClass -> TextShowClass -> Bool
Eq, Eq TextShowClass
Eq TextShowClass =>
(TextShowClass -> TextShowClass -> Ordering)
-> (TextShowClass -> TextShowClass -> Bool)
-> (TextShowClass -> TextShowClass -> Bool)
-> (TextShowClass -> TextShowClass -> Bool)
-> (TextShowClass -> TextShowClass -> Bool)
-> (TextShowClass -> TextShowClass -> TextShowClass)
-> (TextShowClass -> TextShowClass -> TextShowClass)
-> Ord TextShowClass
TextShowClass -> TextShowClass -> Bool
TextShowClass -> TextShowClass -> Ordering
TextShowClass -> TextShowClass -> TextShowClass
forall a.
Eq a =>
(a -> a -> Ordering)
-> (a -> a -> Bool)
-> (a -> a -> Bool)
-> (a -> a -> Bool)
-> (a -> a -> Bool)
-> (a -> a -> a)
-> (a -> a -> a)
-> Ord a
min :: TextShowClass -> TextShowClass -> TextShowClass
$cmin :: TextShowClass -> TextShowClass -> TextShowClass
max :: TextShowClass -> TextShowClass -> TextShowClass
$cmax :: TextShowClass -> TextShowClass -> TextShowClass
>= :: TextShowClass -> TextShowClass -> Bool
$c>= :: TextShowClass -> TextShowClass -> Bool
> :: TextShowClass -> TextShowClass -> Bool
$c> :: TextShowClass -> TextShowClass -> Bool
<= :: TextShowClass -> TextShowClass -> Bool
$c<= :: TextShowClass -> TextShowClass -> Bool
< :: TextShowClass -> TextShowClass -> Bool
$c< :: TextShowClass -> TextShowClass -> Bool
compare :: TextShowClass -> TextShowClass -> Ordering
$ccompare :: TextShowClass -> TextShowClass -> Ordering
$cp1Ord :: Eq TextShowClass
Ord)

-- | A representation of which TextShow method is being used to
-- implement something.
data TextShowFun = ShowbPrec | ShowtPrec | ShowtlPrec

fromStringName :: TextShowFun -> Name
fromStringName :: TextShowFun -> Name
fromStringName ShowbPrec  = 'TB.fromString
fromStringName ShowtPrec  = 'TS.pack
fromStringName ShowtlPrec = 'TL.pack

singletonName :: TextShowFun -> Name
singletonName :: TextShowFun -> Name
singletonName ShowbPrec  = 'TB.singleton
singletonName ShowtPrec  = 'TS.singleton
singletonName ShowtlPrec = 'TL.singleton

showParenName :: TextShowFun -> Name
showParenName :: TextShowFun -> Name
showParenName ShowbPrec  = 'showbParen
showParenName ShowtPrec  = 'showtParen
showParenName ShowtlPrec = 'showtlParen

showCommaSpaceName :: TextShowFun -> Name
showCommaSpaceName :: TextShowFun -> Name
showCommaSpaceName ShowbPrec  = 'showbCommaSpace
showCommaSpaceName ShowtPrec  = 'showtCommaSpace
showCommaSpaceName ShowtlPrec = 'showtlCommaSpace

showSpaceName :: TextShowFun -> Name
showSpaceName :: TextShowFun -> Name
showSpaceName ShowbPrec  = 'showbSpace
showSpaceName ShowtPrec  = 'showtSpace
showSpaceName ShowtlPrec = 'showtlSpace

showPrecConstName :: TextShowClass -> TextShowFun -> Name
showPrecConstName :: TextShowClass -> TextShowFun -> Name
showPrecConstName tsClass :: TextShowClass
tsClass  ShowbPrec  = TextShowClass -> Name
showbPrecConstName TextShowClass
tsClass
showPrecConstName TextShow ShowtPrec  = 'showtPrecConst
showPrecConstName TextShow ShowtlPrec = 'showtlPrecConst
showPrecConstName _        _          = String -> Name
forall a. HasCallStack => String -> a
error "showPrecConstName"

showbPrecConstName :: TextShowClass -> Name
showbPrecConstName :: TextShowClass -> Name
showbPrecConstName TextShow  = 'showbPrecConst
showbPrecConstName TextShow1 = 'liftShowbPrecConst
showbPrecConstName TextShow2 = 'liftShowbPrec2Const

textShowClassName :: TextShowClass -> Name
textShowClassName :: TextShowClass -> Name
textShowClassName TextShow  = ''TextShow
textShowClassName TextShow1 = ''TextShow1
textShowClassName TextShow2 = ''TextShow2

showPrecName :: TextShowClass -> TextShowFun -> Name
showPrecName :: TextShowClass -> TextShowFun -> Name
showPrecName tsClass :: TextShowClass
tsClass  ShowbPrec  = TextShowClass -> Name
showbPrecName TextShowClass
tsClass
showPrecName TextShow ShowtPrec  = 'showtPrec
showPrecName TextShow ShowtlPrec = 'showtlPrec
showPrecName _        _          = String -> Name
forall a. HasCallStack => String -> a
error "showPrecName"

showbPrecName :: TextShowClass -> Name
showbPrecName :: TextShowClass -> Name
showbPrecName TextShow  = 'showbPrec
showbPrecName TextShow1 = 'liftShowbPrec
showbPrecName TextShow2 = 'liftShowbPrec2

showListName :: TextShowClass -> TextShowFun -> Name
showListName :: TextShowClass -> TextShowFun -> Name
showListName tsClass :: TextShowClass
tsClass  ShowbPrec  = TextShowClass -> Name
showbListName TextShowClass
tsClass
showListName TextShow ShowtPrec  = 'showtPrec
showListName TextShow ShowtlPrec = 'showtlPrec
showListName _        _          = String -> Name
forall a. HasCallStack => String -> a
error "showListName"

showbListName :: TextShowClass -> Name
showbListName :: TextShowClass -> Name
showbListName TextShow  = 'showbList
showbListName TextShow1 = 'liftShowbList
showbListName TextShow2 = 'liftShowbList2

showPrecOrListName :: Bool -- ^ showbListName if True, showbPrecName if False
                   -> TextShowClass
                   -> TextShowFun
                   -> Name
showPrecOrListName :: Bool -> TextShowClass -> TextShowFun -> Name
showPrecOrListName False = TextShowClass -> TextShowFun -> Name
showPrecName
showPrecOrListName True  = TextShowClass -> TextShowFun -> Name
showListName

-- | A type-restricted version of 'const'. This is useful when generating the lambda
-- expression in 'makeShowbPrec' for a data type with only nullary constructors (since
-- the expression wouldn't depend on the precedence). For example, if you had @data
-- Nullary = Nullary@ and attempted to run @$(makeShowbPrec ''Nullary) Nullary@, simply
-- ignoring the precedence argument would cause the type signature of @$(makeShowbPrec
-- ''Nullary)@ to be @a -> Nullary -> Builder@, not @Int -> Nullary -> Builder@.
showbPrecConst :: Builder
               -> Int -> a -> Builder
showbPrecConst :: Builder -> Int -> a -> Builder
showbPrecConst b :: Builder
b _ _ = Builder
b

showtPrecConst :: TS.Text
               -> Int -> a -> TS.Text
showtPrecConst :: Text -> Int -> a -> Text
showtPrecConst t :: Text
t _ _ = Text
t

showtlPrecConst :: TL.Text
                -> Int -> a -> TL.Text
showtlPrecConst :: Text -> Int -> a -> Text
showtlPrecConst tl :: Text
tl _ _ = Text
tl

liftShowbPrecConst :: Builder
                   -> (Int -> a -> Builder) -> ([a] -> Builder)
                   -> Int -> f a -> Builder
liftShowbPrecConst :: Builder
-> (Int -> a -> Builder)
-> ([a] -> Builder)
-> Int
-> f a
-> Builder
liftShowbPrecConst b :: Builder
b _ _ _ _ = Builder
b

liftShowbPrec2Const :: Builder
                    -> (Int -> a -> Builder) -> ([a] -> Builder)
                    -> (Int -> b -> Builder) -> ([b] -> Builder)
                    -> Int -> f a b -> Builder
liftShowbPrec2Const :: Builder
-> (Int -> a -> Builder)
-> ([a] -> Builder)
-> (Int -> b -> Builder)
-> ([b] -> Builder)
-> Int
-> f a b
-> Builder
liftShowbPrec2Const b :: Builder
b _ _ _ _ _ _ = Builder
b

-------------------------------------------------------------------------------
-- StarKindStatus
-------------------------------------------------------------------------------

-- | Whether a type is not of kind *, is of kind *, or is a kind variable.
data StarKindStatus = NotKindStar
                    | KindStar
                    | IsKindVar Name
  deriving StarKindStatus -> StarKindStatus -> Bool
(StarKindStatus -> StarKindStatus -> Bool)
-> (StarKindStatus -> StarKindStatus -> Bool) -> Eq StarKindStatus
forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
/= :: StarKindStatus -> StarKindStatus -> Bool
$c/= :: StarKindStatus -> StarKindStatus -> Bool
== :: StarKindStatus -> StarKindStatus -> Bool
$c== :: StarKindStatus -> StarKindStatus -> Bool
Eq

-- | Does a Type have kind * or k (for some kind variable k)?
canRealizeKindStar :: Type -> StarKindStatus
canRealizeKindStar :: Type -> StarKindStatus
canRealizeKindStar t :: Type
t
  | Type -> Bool
hasKindStar Type
t = StarKindStatus
KindStar
  | Bool
otherwise = case Type
t of
#if MIN_VERSION_template_haskell(2,8,0)
                     SigT _ (VarT k :: Name
k) -> Name -> StarKindStatus
IsKindVar Name
k
#endif
                     _               -> StarKindStatus
NotKindStar

-- | Returns 'Just' the kind variable 'Name' of a 'StarKindStatus' if it exists.
-- Otherwise, returns 'Nothing'.
starKindStatusToName :: StarKindStatus -> Maybe Name
starKindStatusToName :: StarKindStatus -> Maybe Name
starKindStatusToName (IsKindVar n :: Name
n) = Name -> Maybe Name
forall a. a -> Maybe a
Just Name
n
starKindStatusToName _             = Maybe Name
forall a. Maybe a
Nothing

-- | Concat together all of the StarKindStatuses that are IsKindVar and extract
-- the kind variables' Names out.
catKindVarNames :: [StarKindStatus] -> [Name]
catKindVarNames :: [StarKindStatus] -> [Name]
catKindVarNames = (StarKindStatus -> Maybe Name) -> [StarKindStatus] -> [Name]
forall a b. (a -> Maybe b) -> [a] -> [b]
mapMaybe StarKindStatus -> Maybe Name
starKindStatusToName

-------------------------------------------------------------------------------
-- PrimShow
-------------------------------------------------------------------------------

data PrimShow = PrimShow
  { PrimShow -> Q Exp -> Q Exp
primShowBoxer      :: Q Exp -> Q Exp
  , PrimShow -> TextShowFun -> Q Exp
primShowPostfixMod :: TextShowFun -> Q Exp
  , PrimShow -> TextShowFun -> Q Exp -> Q Exp
primShowConv       :: TextShowFun -> Q Exp -> Q Exp
  }

primShowTbl :: Map Name PrimShow
primShowTbl :: Map Name PrimShow
primShowTbl = [(Name, PrimShow)] -> Map Name PrimShow
forall k a. Ord k => [(k, a)] -> Map k a
Map.fromList
    [ (''Char#,   PrimShow :: (Q Exp -> Q Exp)
-> (TextShowFun -> Q Exp)
-> (TextShowFun -> Q Exp -> Q Exp)
-> PrimShow
PrimShow
                    { primShowBoxer :: Q Exp -> Q Exp
primShowBoxer      = Q Exp -> Q Exp -> Q Exp
appE (Name -> Q Exp
conE 'C#)
                    , primShowPostfixMod :: TextShowFun -> Q Exp
primShowPostfixMod = TextShowFun -> Q Exp
oneHashE
                    , primShowConv :: TextShowFun -> Q Exp -> Q Exp
primShowConv       = \_ x :: Q Exp
x -> Q Exp
x
                    })
    , (''Double#, PrimShow :: (Q Exp -> Q Exp)
-> (TextShowFun -> Q Exp)
-> (TextShowFun -> Q Exp -> Q Exp)
-> PrimShow
PrimShow
                    { primShowBoxer :: Q Exp -> Q Exp
primShowBoxer      = Q Exp -> Q Exp -> Q Exp
appE (Name -> Q Exp
conE 'D#)
                    , primShowPostfixMod :: TextShowFun -> Q Exp
primShowPostfixMod = TextShowFun -> Q Exp
twoHashE
                    , primShowConv :: TextShowFun -> Q Exp -> Q Exp
primShowConv       = \_ x :: Q Exp
x -> Q Exp
x
                    })
    , (''Float#,  PrimShow :: (Q Exp -> Q Exp)
-> (TextShowFun -> Q Exp)
-> (TextShowFun -> Q Exp -> Q Exp)
-> PrimShow
PrimShow
                    { primShowBoxer :: Q Exp -> Q Exp
primShowBoxer      = Q Exp -> Q Exp -> Q Exp
appE (Name -> Q Exp
conE 'F#)
                    , primShowPostfixMod :: TextShowFun -> Q Exp
primShowPostfixMod = TextShowFun -> Q Exp
oneHashE
                    , primShowConv :: TextShowFun -> Q Exp -> Q Exp
primShowConv       = \_ x :: Q Exp
x -> Q Exp
x
                    })
    , (''Int#,    PrimShow :: (Q Exp -> Q Exp)
-> (TextShowFun -> Q Exp)
-> (TextShowFun -> Q Exp -> Q Exp)
-> PrimShow
PrimShow
                    { primShowBoxer :: Q Exp -> Q Exp
primShowBoxer      = Q Exp -> Q Exp -> Q Exp
appE (Name -> Q Exp
conE 'I#)
                    , primShowPostfixMod :: TextShowFun -> Q Exp
primShowPostfixMod = TextShowFun -> Q Exp
oneHashE
                    , primShowConv :: TextShowFun -> Q Exp -> Q Exp
primShowConv       = \_ x :: Q Exp
x -> Q Exp
x
                    })
    , (''Word#,   PrimShow :: (Q Exp -> Q Exp)
-> (TextShowFun -> Q Exp)
-> (TextShowFun -> Q Exp -> Q Exp)
-> PrimShow
PrimShow
                    { primShowBoxer :: Q Exp -> Q Exp
primShowBoxer      = Q Exp -> Q Exp -> Q Exp
appE (Name -> Q Exp
conE 'W#)
                    , primShowPostfixMod :: TextShowFun -> Q Exp
primShowPostfixMod = TextShowFun -> Q Exp
twoHashE
                    , primShowConv :: TextShowFun -> Q Exp -> Q Exp
primShowConv       = \_ x :: Q Exp
x -> Q Exp
x
                    })
#if MIN_VERSION_base(4,13,0)
    , (''Int8#,   PrimShow :: (Q Exp -> Q Exp)
-> (TextShowFun -> Q Exp)
-> (TextShowFun -> Q Exp -> Q Exp)
-> PrimShow
PrimShow
                    { primShowBoxer :: Q Exp -> Q Exp
primShowBoxer      = Q Exp -> Q Exp -> Q Exp
appE (Name -> Q Exp
conE 'I#) (Q Exp -> Q Exp) -> (Q Exp -> Q Exp) -> Q Exp -> Q Exp
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Q Exp -> Q Exp -> Q Exp
appE (Name -> Q Exp
varE 'extendInt8#)
                    , primShowPostfixMod :: TextShowFun -> Q Exp
primShowPostfixMod = TextShowFun -> Q Exp
oneHashE
                    , primShowConv :: TextShowFun -> Q Exp -> Q Exp
primShowConv       = String -> TextShowFun -> Q Exp -> Q Exp
mkNarrowE "narrowInt8#"
                    })
    , (''Int16#,  PrimShow :: (Q Exp -> Q Exp)
-> (TextShowFun -> Q Exp)
-> (TextShowFun -> Q Exp -> Q Exp)
-> PrimShow
PrimShow
                    { primShowBoxer :: Q Exp -> Q Exp
primShowBoxer      = Q Exp -> Q Exp -> Q Exp
appE (Name -> Q Exp
conE 'I#) (Q Exp -> Q Exp) -> (Q Exp -> Q Exp) -> Q Exp -> Q Exp
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Q Exp -> Q Exp -> Q Exp
appE (Name -> Q Exp
varE 'extendInt16#)
                    , primShowPostfixMod :: TextShowFun -> Q Exp
primShowPostfixMod = TextShowFun -> Q Exp
oneHashE
                    , primShowConv :: TextShowFun -> Q Exp -> Q Exp
primShowConv       = String -> TextShowFun -> Q Exp -> Q Exp
mkNarrowE "narrowInt16#"
                    })
    , (''Word8#,  PrimShow :: (Q Exp -> Q Exp)
-> (TextShowFun -> Q Exp)
-> (TextShowFun -> Q Exp -> Q Exp)
-> PrimShow
PrimShow
                    { primShowBoxer :: Q Exp -> Q Exp
primShowBoxer      = Q Exp -> Q Exp -> Q Exp
appE (Name -> Q Exp
conE 'W#) (Q Exp -> Q Exp) -> (Q Exp -> Q Exp) -> Q Exp -> Q Exp
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Q Exp -> Q Exp -> Q Exp
appE (Name -> Q Exp
varE 'extendWord8#)
                    , primShowPostfixMod :: TextShowFun -> Q Exp
primShowPostfixMod = TextShowFun -> Q Exp
twoHashE
                    , primShowConv :: TextShowFun -> Q Exp -> Q Exp
primShowConv       = String -> TextShowFun -> Q Exp -> Q Exp
mkNarrowE "narrowWord8#"
                    })
    , (''Word16#, PrimShow :: (Q Exp -> Q Exp)
-> (TextShowFun -> Q Exp)
-> (TextShowFun -> Q Exp -> Q Exp)
-> PrimShow
PrimShow
                    { primShowBoxer :: Q Exp -> Q Exp
primShowBoxer      = Q Exp -> Q Exp -> Q Exp
appE (Name -> Q Exp
conE 'W#) (Q Exp -> Q Exp) -> (Q Exp -> Q Exp) -> Q Exp -> Q Exp
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Q Exp -> Q Exp -> Q Exp
appE (Name -> Q Exp
varE 'extendWord16#)
                    , primShowPostfixMod :: TextShowFun -> Q Exp
primShowPostfixMod = TextShowFun -> Q Exp
twoHashE
                    , primShowConv :: TextShowFun -> Q Exp -> Q Exp
primShowConv       = String -> TextShowFun -> Q Exp -> Q Exp
mkNarrowE "narrowWord16#"
                    })
#endif
    ]

#if MIN_VERSION_base(4,13,0)
mkNarrowE :: String -> TextShowFun -> Q Exp -> Q Exp
mkNarrowE :: String -> TextShowFun -> Q Exp -> Q Exp
mkNarrowE narrowStr :: String
narrowStr tsFun :: TextShowFun
tsFun e :: Q Exp
e =
  (Q Exp -> Q Exp -> Q Exp) -> Q Exp -> [Q Exp] -> Q Exp
forall (t :: * -> *) a b.
Foldable t =>
(a -> b -> b) -> b -> t a -> b
foldr (Q Exp -> Q Exp -> Q Exp -> Q Exp
`infixApp` [| (<>) |])
        (Name -> Q Exp
varE (TextShowFun -> Name
singletonName TextShowFun
tsFun) Q Exp -> Q Exp -> Q Exp
`appE` Char -> Q Exp
charE ')')
        [ Name -> Q Exp
varE (TextShowFun -> Name
fromStringName TextShowFun
tsFun) Q Exp -> Q Exp -> Q Exp
`appE` String -> Q Exp
stringE ('('Char -> String -> String
forall a. a -> [a] -> [a]
:String
narrowStr String -> String -> String
forall a. [a] -> [a] -> [a]
++ " ")
        , Q Exp
e
        ]
#endif

oneHashE, twoHashE :: TextShowFun -> Q Exp
oneHashE :: TextShowFun -> Q Exp
oneHashE tsFun :: TextShowFun
tsFun = Name -> Q Exp
varE (TextShowFun -> Name
singletonName TextShowFun
tsFun)  Q Exp -> Q Exp -> Q Exp
`appE` Char -> Q Exp
charE '#'
twoHashE :: TextShowFun -> Q Exp
twoHashE tsFun :: TextShowFun
tsFun = Name -> Q Exp
varE (TextShowFun -> Name
fromStringName TextShowFun
tsFun) Q Exp -> Q Exp -> Q Exp
`appE` String -> Q Exp
stringE "##"

-------------------------------------------------------------------------------
-- Assorted utilities
-------------------------------------------------------------------------------

integerE :: Int -> Q Exp
integerE :: Int -> Q Exp
integerE = Lit -> Q Exp
litE (Lit -> Q Exp) -> (Int -> Lit) -> Int -> Q Exp
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Integer -> Lit
integerL (Integer -> Lit) -> (Int -> Integer) -> Int -> Lit
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Int -> Integer
forall a b. (Integral a, Num b) => a -> b
fromIntegral

charE :: Char -> Q Exp
charE :: Char -> Q Exp
charE = Lit -> Q Exp
litE (Lit -> Q Exp) -> (Char -> Lit) -> Char -> Q Exp
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Char -> Lit
charL

-- | Returns True if a Type has kind *.
hasKindStar :: Type -> Bool
hasKindStar :: Type -> Bool
hasKindStar VarT{}         = Bool
True
#if MIN_VERSION_template_haskell(2,8,0)
hasKindStar (SigT _ StarT) = Bool
True
#else
hasKindStar (SigT _ StarK) = True
#endif
hasKindStar _              = Bool
False

-- Returns True is a kind is equal to *, or if it is a kind variable.
isStarOrVar :: Kind -> Bool
#if MIN_VERSION_template_haskell(2,8,0)
isStarOrVar :: Type -> Bool
isStarOrVar StarT  = Bool
True
isStarOrVar VarT{} = Bool
True
#else
isStarOrVar StarK  = True
#endif
isStarOrVar _      = Bool
False

-- Generate a list of fresh names with a common prefix, and numbered suffixes.
newNameList :: String -> Int -> Q [Name]
newNameList :: String -> Int -> Q [Name]
newNameList prefix :: String
prefix n :: Int
n = (Int -> Q Name) -> [Int] -> Q [Name]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
mapM (String -> Q Name
newName (String -> Q Name) -> (Int -> String) -> Int -> Q Name
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (String
prefix String -> String -> String
forall a. [a] -> [a] -> [a]
++) (String -> String) -> (Int -> String) -> Int -> String
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Int -> String
forall a. Show a => a -> String
show) [1..Int
n]

-- | @hasKindVarChain n kind@ Checks if @kind@ is of the form
-- k_0 -> k_1 -> ... -> k_(n-1), where k0, k1, ..., and k_(n-1) can be * or
-- kind variables.
hasKindVarChain :: Int -> Type -> Maybe [Name]
hasKindVarChain :: Int -> Type -> Maybe [Name]
hasKindVarChain kindArrows :: Int
kindArrows t :: Type
t =
  let uk :: NonEmpty Type
uk = Type -> NonEmpty Type
uncurryKind (Type -> Type
tyKind Type
t)
  in if (NonEmpty Type -> Int
forall (t :: * -> *) a. Foldable t => t a -> Int
length NonEmpty Type
uk Int -> Int -> Int
forall a. Num a => a -> a -> a
- 1 Int -> Int -> Bool
forall a. Eq a => a -> a -> Bool
== Int
kindArrows) Bool -> Bool -> Bool
&& (Type -> Bool) -> NonEmpty Type -> Bool
forall (t :: * -> *) a. Foldable t => (a -> Bool) -> t a -> Bool
all Type -> Bool
isStarOrVar NonEmpty Type
uk
        then [Name] -> Maybe [Name]
forall a. a -> Maybe a
Just ((Type -> [Name]) -> NonEmpty Type -> [Name]
forall (t :: * -> *) a b. Foldable t => (a -> [b]) -> t a -> [b]
concatMap Type -> [Name]
forall a. TypeSubstitution a => a -> [Name]
freeVariables NonEmpty Type
uk)
        else Maybe [Name]
forall a. Maybe a
Nothing

-- | If a Type is a SigT, returns its kind signature. Otherwise, return *.
tyKind :: Type -> Kind
tyKind :: Type -> Type
tyKind (SigT _ k :: Type
k) = Type
k
tyKind _          = Type
starK

-- | A mapping of type variable Names to their show function Names. For example, in a
-- TextShow2 declaration, a TyVarMap might look like (a ~> sp1, b ~> sp2), where
-- a and b are the last two type variables of the datatype, and sp1 and sp2 are the two
-- functions which show their respective type variables.
type TyVarMap = Map Name (Name, Name)

-- | Checks if a 'Name' represents a tuple type constructor (other than '()')
isNonUnitTuple :: Name -> Bool
isNonUnitTuple :: Name -> Bool
isNonUnitTuple = String -> Bool
isTupleString (String -> Bool) -> (Name -> String) -> Name -> Bool
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Name -> String
nameBase

-- | Parenthesize an infix constructor name if it is being applied as a prefix
-- function (e.g., data Amp a = (:&) a a)
parenInfixConName :: Name -> ShowS
parenInfixConName :: Name -> String -> String
parenInfixConName conName :: Name
conName =
    let conNameBase :: String
conNameBase = Name -> String
nameBase Name
conName
     in Bool -> (String -> String) -> String -> String
showParen (String -> Bool
isInfixDataCon String
conNameBase) ((String -> String) -> String -> String)
-> (String -> String) -> String -> String
forall a b. (a -> b) -> a -> b
$ String -> String -> String
showString String
conNameBase

-- | Applies a typeclass constraint to a type.
applyClass :: Name -> Name -> Pred
#if MIN_VERSION_template_haskell(2,10,0)
applyClass :: Name -> Name -> Type
applyClass con :: Name
con t :: Name
t = Type -> Type -> Type
AppT (Name -> Type
ConT Name
con) (Name -> Type
VarT Name
t)
#else
applyClass con t = ClassP con [VarT t]
#endif

-- | Checks to see if the last types in a data family instance can be safely eta-
-- reduced (i.e., dropped), given the other types. This checks for three conditions:
--
-- (1) All of the dropped types are type variables
-- (2) All of the dropped types are distinct
-- (3) None of the remaining types mention any of the dropped types
canEtaReduce :: [Type] -> [Type] -> Bool
canEtaReduce :: Cxt -> Cxt -> Bool
canEtaReduce remaining :: Cxt
remaining dropped :: Cxt
dropped =
       (Type -> Bool) -> Cxt -> Bool
forall (t :: * -> *) a. Foldable t => (a -> Bool) -> t a -> Bool
all Type -> Bool
isTyVar Cxt
dropped
    Bool -> Bool -> Bool
&& [Name] -> Bool
forall a. Ord a => [a] -> Bool
allDistinct [Name]
droppedNames -- Make sure not to pass something of type [Type], since Type
                                -- didn't have an Ord instance until template-haskell-2.10.0.0
    Bool -> Bool -> Bool
&& Bool -> Bool
not ((Type -> Bool) -> Cxt -> Bool
forall (t :: * -> *) a. Foldable t => (a -> Bool) -> t a -> Bool
any (Type -> [Name] -> Bool
`mentionsName` [Name]
droppedNames) Cxt
remaining)
  where
    droppedNames :: [Name]
    droppedNames :: [Name]
droppedNames = (Type -> Name) -> Cxt -> [Name]
forall a b. (a -> b) -> [a] -> [b]
map Type -> Name
varTToName Cxt
dropped

-- | Extract Just the Name from a type variable. If the argument Type is not a
-- type variable, return Nothing.
varTToName_maybe :: Type -> Maybe Name
varTToName_maybe :: Type -> Maybe Name
varTToName_maybe (VarT n :: Name
n)   = Name -> Maybe Name
forall a. a -> Maybe a
Just Name
n
varTToName_maybe (SigT t :: Type
t _) = Type -> Maybe Name
varTToName_maybe Type
t
varTToName_maybe _          = Maybe Name
forall a. Maybe a
Nothing

-- | Extract the Name from a type variable. If the argument Type is not a
-- type variable, throw an error.
varTToName :: Type -> Name
varTToName :: Type -> Name
varTToName = Name -> Maybe Name -> Name
forall a. a -> Maybe a -> a
fromMaybe (String -> Name
forall a. HasCallStack => String -> a
error "Not a type variable!") (Maybe Name -> Name) -> (Type -> Maybe Name) -> Type -> Name
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Type -> Maybe Name
varTToName_maybe

-- | Peel off a kind signature from a Type (if it has one).
unSigT :: Type -> Type
unSigT :: Type -> Type
unSigT (SigT t :: Type
t _) = Type
t
unSigT t :: Type
t          = Type
t

-- | Is the given type a variable?
isTyVar :: Type -> Bool
isTyVar :: Type -> Bool
isTyVar (VarT _)   = Bool
True
isTyVar (SigT t :: Type
t _) = Type -> Bool
isTyVar Type
t
isTyVar _          = Bool
False

-- | Is the given type a type family constructor (and not a data family constructor)?
isTyFamily :: Type -> Q Bool
isTyFamily :: Type -> Q Bool
isTyFamily (ConT n :: Name
n) = do
    Info
info <- Name -> Q Info
reify Name
n
    Bool -> Q Bool
forall (m :: * -> *) a. Monad m => a -> m a
return (Bool -> Q Bool) -> Bool -> Q Bool
forall a b. (a -> b) -> a -> b
$ case Info
info of
#if MIN_VERSION_template_haskell(2,11,0)
         FamilyI OpenTypeFamilyD{} _       -> Bool
True
#else
         FamilyI (FamilyD TypeFam _ _ _) _ -> True
#endif
#if MIN_VERSION_template_haskell(2,9,0)
         FamilyI ClosedTypeFamilyD{} _     -> Bool
True
#endif
         _ -> Bool
False
isTyFamily _ = Bool -> Q Bool
forall (m :: * -> *) a. Monad m => a -> m a
return Bool
False

-- | Are all of the items in a list (which have an ordering) distinct?
--
-- This uses Set (as opposed to nub) for better asymptotic time complexity.
allDistinct :: Ord a => [a] -> Bool
allDistinct :: [a] -> Bool
allDistinct = Set a -> [a] -> Bool
forall a. Ord a => Set a -> [a] -> Bool
allDistinct' Set a
forall a. Set a
Set.empty
  where
    allDistinct' :: Ord a => Set a -> [a] -> Bool
    allDistinct' :: Set a -> [a] -> Bool
allDistinct' uniqs :: Set a
uniqs (x :: a
x:xs :: [a]
xs)
        | a
x a -> Set a -> Bool
forall a. Ord a => a -> Set a -> Bool
`Set.member` Set a
uniqs = Bool
False
        | Bool
otherwise            = Set a -> [a] -> Bool
forall a. Ord a => Set a -> [a] -> Bool
allDistinct' (a -> Set a -> Set a
forall a. Ord a => a -> Set a -> Set a
Set.insert a
x Set a
uniqs) [a]
xs
    allDistinct' _ _           = Bool
True

-- | Does the given type mention any of the Names in the list?
mentionsName :: Type -> [Name] -> Bool
mentionsName :: Type -> [Name] -> Bool
mentionsName = Type -> [Name] -> Bool
go
  where
    go :: Type -> [Name] -> Bool
    go :: Type -> [Name] -> Bool
go (AppT t1 :: Type
t1 t2 :: Type
t2) names :: [Name]
names = Type -> [Name] -> Bool
go Type
t1 [Name]
names Bool -> Bool -> Bool
|| Type -> [Name] -> Bool
go Type
t2 [Name]
names
    go (SigT t :: Type
t _k :: Type
_k)  names :: [Name]
names = Type -> [Name] -> Bool
go Type
t [Name]
names
#if MIN_VERSION_template_haskell(2,8,0)
                              Bool -> Bool -> Bool
|| Type -> [Name] -> Bool
go Type
_k [Name]
names
#endif
    go (VarT n :: Name
n)     names :: [Name]
names = Name
n Name -> [Name] -> Bool
forall (t :: * -> *) a. (Foldable t, Eq a) => a -> t a -> Bool
`elem` [Name]
names
    go _            _     = Bool
False

-- | Does an instance predicate mention any of the Names in the list?
predMentionsName :: Pred -> [Name] -> Bool
#if MIN_VERSION_template_haskell(2,10,0)
predMentionsName :: Type -> [Name] -> Bool
predMentionsName = Type -> [Name] -> Bool
mentionsName
#else
predMentionsName (ClassP n tys) names = n `elem` names || any (`mentionsName` names) tys
predMentionsName (EqualP t1 t2) names = mentionsName t1 names || mentionsName t2 names
#endif

-- | Construct a type via curried application.
applyTy :: Type -> [Type] -> Type
applyTy :: Type -> Cxt -> Type
applyTy = (Type -> Type -> Type) -> Type -> Cxt -> Type
forall (t :: * -> *) b a.
Foldable t =>
(b -> a -> b) -> b -> t a -> b
foldl' Type -> Type -> Type
AppT

-- | Fully applies a type constructor to its type variables.
applyTyCon :: Name -> [Type] -> Type
applyTyCon :: Name -> Cxt -> Type
applyTyCon = Type -> Cxt -> Type
applyTy (Type -> Cxt -> Type) -> (Name -> Type) -> Name -> Cxt -> Type
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Name -> Type
ConT

-- | Split an applied type into its individual components. For example, this:
--
-- @
-- Either Int Char
-- @
--
-- would split to this:
--
-- @
-- [Either, Int, Char]
-- @
unapplyTy :: Type -> NonEmpty Type
unapplyTy :: Type -> NonEmpty Type
unapplyTy = NonEmpty Type -> NonEmpty Type
forall a. NonEmpty a -> NonEmpty a
NE.reverse (NonEmpty Type -> NonEmpty Type)
-> (Type -> NonEmpty Type) -> Type -> NonEmpty Type
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Type -> NonEmpty Type
go
  where
    go :: Type -> NonEmpty Type
    go :: Type -> NonEmpty Type
go (AppT t1 :: Type
t1 t2 :: Type
t2)    = Type
t2 Type -> NonEmpty Type -> NonEmpty Type
forall a. a -> NonEmpty a -> NonEmpty a
<| Type -> NonEmpty Type
go Type
t1
    go (SigT t :: Type
t _)      = Type -> NonEmpty Type
go Type
t
    go (ForallT _ _ t :: Type
t) = Type -> NonEmpty Type
go Type
t
    go t :: Type
t               = Type
t Type -> Cxt -> NonEmpty Type
forall a. a -> [a] -> NonEmpty a
:| []

-- | Split a type signature by the arrows on its spine. For example, this:
--
-- @
-- (Int -> String) -> Char -> ()
-- @
--
-- would split to this:
--
-- @
-- [Int -> String, Char, ()]
-- @
uncurryTy :: Type -> NonEmpty Type
uncurryTy :: Type -> NonEmpty Type
uncurryTy (AppT (AppT ArrowT t1 :: Type
t1) t2 :: Type
t2) = Type
t1 Type -> NonEmpty Type -> NonEmpty Type
forall a. a -> NonEmpty a -> NonEmpty a
<| Type -> NonEmpty Type
uncurryTy Type
t2
uncurryTy (SigT t :: Type
t _)                 = Type -> NonEmpty Type
uncurryTy Type
t
uncurryTy (ForallT _ _ t :: Type
t)            = Type -> NonEmpty Type
uncurryTy Type
t
uncurryTy t :: Type
t                          = Type
t Type -> Cxt -> NonEmpty Type
forall a. a -> [a] -> NonEmpty a
:| []

-- | Like uncurryType, except on a kind level.
uncurryKind :: Kind -> NonEmpty Kind
#if MIN_VERSION_template_haskell(2,8,0)
uncurryKind :: Type -> NonEmpty Type
uncurryKind = Type -> NonEmpty Type
uncurryTy
#else
uncurryKind (ArrowK k1 k2) = k1 <| uncurryKind k2
uncurryKind k              = k :| []
#endif

createKindChain :: Int -> Kind
createKindChain :: Int -> Type
createKindChain = Type -> Int -> Type
go Type
starK
  where
    go :: Kind -> Int -> Kind
    go :: Type -> Int -> Type
go k :: Type
k !Int
0 = Type
k
    go k :: Type
k !Int
n = Type -> Int -> Type
go (Type -> Type -> Type
arrowKCompat Type
starK Type
k) (Int
n Int -> Int -> Int
forall a. Num a => a -> a -> a
- 1)

isNullaryCon :: ConstructorInfo -> Bool
isNullaryCon :: ConstructorInfo -> Bool
isNullaryCon (ConstructorInfo { constructorFields :: ConstructorInfo -> Cxt
constructorFields = [] }) = Bool
True
isNullaryCon _                                            = Bool
False

interleave :: [a] -> [a] -> [a]
interleave :: [a] -> [a] -> [a]
interleave (a1 :: a
a1:a1s :: [a]
a1s) (a2 :: a
a2:a2s :: [a]
a2s) = a
a1a -> [a] -> [a]
forall a. a -> [a] -> [a]
:a
a2a -> [a] -> [a]
forall a. a -> [a] -> [a]
:[a] -> [a] -> [a]
forall a. [a] -> [a] -> [a]
interleave [a]
a1s [a]
a2s
interleave _        _        = []

{-
Note [Matching functions with GADT type variables]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

When deriving TextShow2, there is a tricky corner case to consider:

  data Both a b where
    BothCon :: x -> x -> Both x x

Which show functions should be applied to which arguments of BothCon? We have a
choice, since both the function of type (Int -> a -> Builder) and of type
(Int -> b -> Builder) can be applied to either argument. In such a scenario, the
second show function takes precedence over the first show function, so the
derived TextShow2 instance would be:

  instance TextShow Both where
    liftShowsPrec2 sp1 sp2 p (BothCon x1 x2) =
      showbParen (p > appPrec) $
        "BothCon " <> sp2 appPrec1 x1 <> showbSpace <> sp2 appPrec1 x2

This is not an arbitrary choice, as this definition ensures that
liftShowsPrec2 showsPrec = liftShowsPrec for a derived TextShow1 instance for
Both.
-}