README.markdown

base-orphans

Scope

base-orphans defines orphan instances that mimic instances available in later versions of base to a wider (older) range of compilers. base-orphans does not export anything except the orphan instances themselves and complements base-compat.

Note that base-orphans doesn't cover every possible instance. See the What is not covered section for exceptions.

Usage

To use base-orphans, simply import Data.Orphans ().

What is covered

• Alternative, MonadPlus, and MonadZip instances for Proxy
• Alternative, Applicative, Bounded, Data, Enum, Foldable, Functor, Ix, Monad, MonadFix, MonadPlus, MonadZip, and Traversable instances for data types in GHC.Generics
• Alternative, Eq, Ord, Read, Show, Foldable, and Traversable instances for ZipList
• Applicative instance for K1 from GHC.Generics
• Applicative, Bits, Bounded, Data, Enum, Eq1, FiniteBits, Floating, Foldable, Fractional, Functor, Ix, Ord1, Monad, MonadFix, MonadZip, Monoid, Num, Read, Read1, Real, RealFloat, RealFrac, Semigroup, Show, Show1, Storable, and Traversable instances for Down
• Applicative and Alternative instances for ReadP and ReadPrec
• Applicative instance for strict and lazy ST
• Applicative, Foldable, Functor, Monad, and Traversable instances for Complex, Dual, First, Last, Product, and Sum
• Bits instance for Bool
• Bits, Bounded, and Integral instances for CDev
• Bits, Bounded, Enum, FiniteBits, Floating, Fractional, Integral, IsString, Ix, Num, Real, RealFloat, RealFrac, and Storable instances for Const and Identity
• Data instances for All, Any, and Const, IntPtr, WordPtr, WrappedArrow and WrappedMonad
• Data, MonadFix and MonadZip instances for Alt, Dual, First, Last, Product, and Sum
• Data and IsList instances for Version and ZipList
• Eq{1,2}, Ord{1,2}, Show{1,2}, and Read{1,2} instances for (,,) and (,,,)
• Eq and Ord instances for Control.Exception.ErrorCall
• Eq, Ord, Read, and Show instances for data types in GHC.Generics
• Eq, Ord, Bounded, Enum, and Ix instances for Solo
• Eq and Ord instances for Generically1
• Eq and Ord instances for SChar, SNat, and SSymbol
• Eq1, Read1, and Show1 instances for Complex
• Eq1, Ord1, Read1, and Show1 instances for NonEmpty
• Enum, Bounded, Num, Real, Integral, Fractional, RealFrac, Floating, and RealFloat instances for Compose
• Foldable instance for Either, (,) and Const
• Foldable and Traversable instances for Alt from Data.Monoid
• Functor, Applicative, and Monad instances for (,,) a b and (,,,) a b c
• Functor instances for (,,,,) a b c d, (,,,,,) a b c d e, and (,,,,,) a b c d e f
• Functor instance for Handler, ArgOrder, OptDescr, and ArgDescr
• Functor, Applicative, Alternative, and MonadPlus instances for ArrowMonad
• Functor, Applicative, Monad, Alternative, and MonadPlus instances for Kleisli
• Ix instances for tuples of size 6 through 15
• Ix instances for integral types in Foreign.C.Types, Foreign.Ptr, and System.Posix.Types
• Monad instance for (,)
• Monad instance for WrappedMonad
• MonadFail, Monoid, and Semigroup instances for strict ST
• MonadFix and MonadZip instances for Complex
• MonadZip instance for Maybe
• Monoid, Eq, Ord, Read, and Show instances for Const
• Monoid instances for Identity and IO
• Num instance for Sum and Product
• Read instance for Fixed
• Semigroup instances for IO, Event and Lifetime
• Semigroup instances for V1, U1, Par1, Rec1, K1, M1, (:*:), and (:.:) from GHC.Generics. Monoid instances for the same types (except V1).
• Semigroup and Monoid instances for Data.Functor.Product and Data.Functor.Compose
• Show instance for Fingerprint
• Storable instance for (), Complex, and Ratio
• TestEquality instance for Compose
• Traversable instance for Either, (,) and Const
• Ord instance for TyCon and TypeRep.
• Typeable instance for most data types, typeclasses, and promoted data constructors (when possible)

What is not covered

base-orphans does not define the following instances:

• Generic or Generic1 instances. These can be found in the Generics.Deriving.Instances module of the generic-deriving library.
• The Alternative IO and MonadPlus IO instances. These can be found in the Control.Monad.Trans.Error module of the transformers library.

Supported versions of GHC/base

• ghc-9.10.* / base-4.20.*
• ghc-9.8.* / base-4.19.*
• ghc-9.6.* / base-4.18.*
• ghc-9.4.* / base-4.17.*
• ghc-9.2.* / base-4.16.*
• ghc-9.0.* / base-4.15.*
• ghc-8.10.* / base-4.14.*
• ghc-8.8.* / base-4.13.*
• ghc-8.6.* / base-4.12.*
• ghc-8.4.* / base-4.11.*
• ghc-8.2.* / base-4.10.*
• ghc-8.0.* / base-4.9.*

We also make an attempt to keep base-orphans building with GHC HEAD, but due to its volatility, it may not work at any given point in time. If it doesn't, please report it!

Patches are welcome; add tests for new code!