# `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
* Added `Applicative` and `Alternative` instances for `ReadP` and `ReadPrec`
* Added `Bits`, `Bounded`, and `Integral` instances for `CDev`
* Added `Eq` and `Ord` instances for `Control.Exception.ErrorCall`
* Added `Eq`, `Ord`, `Read`, and `Show` instances for data types in `GHC.Generics`
* Added `Functor`, `Applicative`, `Alternative`, and `MonadPlus` instances for `ArrowMonad`
* Added `Functor`, `Applicative`, and `Monad` instances for `First` and `Last`
* Added `Monoid`, `Eq`, `Ord`, `Read`, and `Show` instances for `Const`
* Added `Read` and `Show` instances for `Down`
* Added `Eq`, `Ord`, `Read`, and `Show` instances for `ZipList`
* Added `Monad` instance for `WrappedMonad`
* Added `Data` and `IsList` instances for `Version`
* `Applicative` instance for strict and lazy `ST`
* `Bits` instance for `Bool`
* `Foldable` instance for `Either`, `(,)` and `Const`
* `Functor` instance for `Handler`, `ArgOrder`, `OptDescr`, and `ArgDescr`
* `Num` instance for `Sum` and `Product`
* `Read` instance for `Fixed`
* `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.
## Supported versions of GHC/`base`
* `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!