    {-# LANGUAGE CPP                  #-}

    #if MIN_VERSION_base(4,6,0)
    # if !(MIN_VERSION_base(4,7,0))
    {-# LANGUAGE FlexibleContexts     #-}
    {-# LANGUAGE GADTs                #-}
    {-# LANGUAGE KindSignatures       #-}
    {-# LANGUAGE OverloadedStrings    #-}
    {-# LANGUAGE PolyKinds            #-}
    {-# LANGUAGE UndecidableInstances #-}
    # endif

    {-# OPTIONS_GHC -fno-warn-orphans #-}
    #endif
    {-|
    Module:      TextShow.GHC.TypeLits
    Copyright:   (C) 2014-2017 Ryan Scott
    License:     BSD-style (see the file LICENSE)
    Maintainer:  Ryan Scott
    Stability:   Provisional
    Portability: GHC

    'TextShow' instances for data types in the @GHC.TypeLits@ module.
    Only provided if using @base-4.6.0.0@ or later.

    /Since: 2/
    -}
    module TextShow.GHC.TypeLits () where

    #if MIN_VERSION_base(4,6,0)
    import Prelude ()
    import Prelude.Compat

    import TextShow.Classes (TextShow(..))
    import TextShow.Data.Integral ()

    # if MIN_VERSION_base(4,7,0)
    import GHC.TypeLits (SomeNat(..), SomeSymbol(..), natVal, symbolVal)
    import TextShow.Data.Char ()
    # else
    import Data.Text.Lazy.Builder (singleton)
    import GHC.TypeLits (IsEven(..), IsZero(..), Kind, Sing, SingE(fromSing))
    # endif

    # if MIN_VERSION_base(4,7,0)
    -- | Only available with @base-4.7.0.0@ or later.
    --
    -- /Since: 2/
    instance TextShow SomeNat where
        showbPrec p (SomeNat x) = showbPrec p $ natVal x
        {-# INLINE showbPrec #-}

    -- | Only available with @base-4.7.0.0@ or later.
    --
    -- /Since: 2/
    instance TextShow SomeSymbol where
        showb (SomeSymbol x) = showbList $ symbolVal x
        {-# INLINE showb #-}
    # else
    -- | Only available with @base-4.6@.
    --
    -- /Since: 2/
    instance TextShow (IsEven n) where
        showb IsEvenZero = singleton '0'
        showb (IsEven x) = "(2 * " <> showb x <> singleton ')'
        showb (IsOdd  x) = "(2 * " <> showb x <> " + 1)"
        {-# INLINE showb #-}

    -- | Only available with @base-4.6@.
    --
    -- /Since: 2/
    instance TextShow (IsZero n) where
        showb IsZero     = singleton '0'
        showb (IsSucc n) = singleton '(' <> showb n <> " + 1)"
        {-# INLINE showb #-}

    -- | Only available with @base-4.6@.
    --
    -- /Since: 2/
    instance (SingE (Kind :: k) rep, TextShow rep) => TextShow (Sing (a :: k)) where
        showbPrec p = showbPrec p . fromSing
        {-# INLINE showbPrec #-}
    # endif

    #endif