# `base-orphans`
[][Hackage: base-orphans]
[](http://packdeps.haskellers.com/reverse/base-orphans)
[][Haskell.org]
[][tl;dr Legal: MIT]
[](https://travis-ci.org/haskell-compat/base-orphans)
[Hackage: base-orphans]:
http://hackage.haskell.org/package/base-orphans
"base-orphans package on Hackage"
[Haskell.org]:
http://www.haskell.org
"The Haskell Programming Language"
[tl;dr Legal: MIT]:
https://tldrlegal.com/license/mit-license
"MIT License"
## 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](http://hackage.haskell.org/package/base-compat).
Note that `base-orphans` doesn't cover every possible instance. See the
[What is not covered](#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`, `Data`, `Eq1`, `Foldable`, `Functor`, `Ord1`, `Monad`,
`MonadFix`, `MonadZip`, `Monoid`, `Num`, `Read`, `Read1`, `Semigroup`,
`Show`, `Show1`, 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`, and `WordPtr`
* `Data`, `MonadFix` and `MonadZip` instances for `Alt`, `Dual`, `First`, `Last`,
`Product`, and `Sum`
* `Data` and `IsList` instances for `Version`
* `Eq` and `Ord` instances for `Control.Exception.ErrorCall`
* `Eq`, `Ord`, `Read`, and `Show` instances for data types in `GHC.Generics`
* `Eq1`, `Ord1`, `Read1`, and `Show1` instances for `NonEmpty`
* `Foldable` instance for `Either`, `(,)` and `Const`
* `Foldable` and `Traversable` instances for `Alt` from `Data.Monoid`
* `Functor` instance for `Handler`, `ArgOrder`, `OptDescr`, and `ArgDescr`
* `Functor`, `Applicative`, `Alternative`, and `MonadPlus` instances for `ArrowMonad`
* `Monad` instance for `(,)`
* `Monad` instance for `WrappedMonad`
* `MonadFail`, `Monoid`, and `Semigroup` instances for strict `ST`
* `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`).
* `Show` instance for `Fingerprint`
* `Storable` instance for `()`, `Complex`, and `Ratio`
* `Traversable` instance for `Either`, `(,)` and `Const`
* `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`](https://hackage.haskell.org/package/generic-deriving-1.8.0/docs/Generics-Deriving-Instances.html)
module of the [`generic-deriving`](https://hackage.haskell.org/package/generic-deriving)
library.
* The `Alternative IO` and `MonadPlus IO` instances. These can be found in the
[`Control.Monad.Trans.Error`](http://hackage.haskell.org/package/transformers-0.4.3.0/docs/src/Control-Monad-Trans-Error.html#line-69)
module of the [`transformers`](http://hackage.haskell.org/package/transformers) library.
## Supported versions of GHC/`base`
* `ghc-8.6.4` / `base-4.12.0.0`
* `ghc-8.6.3` / `base-4.12.0.0`
* `ghc-8.6.2` / `base-4.12.0.0`
* `ghc-8.6.1` / `base-4.12.0.0`
* `ghc-8.4.3` / `base-4.11.1.0`
* `ghc-8.4.2` / `base-4.11.1.0`
* `ghc-8.4.1` / `base-4.11.0.0`
* `ghc-8.2.2` / `base-4.10.1.0`
* `ghc-8.2.1` / `base-4.10.0.0`
* `ghc-8.0.2` / `base-4.9.1.0`
* `ghc-8.0.1` / `base-4.9.0.0`
* `ghc-7.10.3` / `base-4.8.2.0`
* `ghc-7.10.2` / `base-4.8.1.0`
* `ghc-7.10.1` / `base-4.8.0.0`
* `ghc-7.8.4` / `base-4.7.0.2`
* `ghc-7.8.3` / `base-4.7.0.1`
* `ghc-7.8.2` / `base-4.7.0.0`
* `ghc-7.8.1` / `base-4.7.0.0`
* `ghc-7.6.3` / `base-4.6.0.1`
* `ghc-7.6.2` / `base-4.6.0.1`
* `ghc-7.6.1` / `base-4.6.0.0`
* `ghc-7.4.2` / `base-4.5.1.0`
* `ghc-7.4.1` / `base-4.5.0.0`
* `ghc-7.2.2` / `base-4.4.1.0`
* `ghc-7.2.1` / `base-4.4.0.0`
* `ghc-7.0.4` / `base-4.3.1.0`
* `ghc-7.0.3` / `base-4.3.1.0`
* `ghc-7.0.2` / `base-4.3.1.0`
* `ghc-7.0.1` / `base-4.3.0.0`
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!