| Description: | 'deriving-compat' provides Template Haskell functions that mimic 'deriving'
extensions that were introduced or modified in recent versions of GHC.
Currently, the following typeclasses/extensions are covered:
* Deriving 'Bounded'
* Deriving 'Enum'
* Deriving 'Ix'
* Deriving 'Eq'
* Deriving 'Ord'
* Deriving 'Read'
* Deriving 'Show'
* 'DeriveFoldable'
* 'DeriveFunctor'
* 'DeriveTraversable'
* 'GeneralizedNewtypeDeriving' (with GHC 8.2 or later)
* 'DerivingVia' (with GHC 8.2 or later)
See the "Data.Deriving" module for a full list of backported changes.
In addition, 'deriving-compat' also provides some additional 'deriving'
functionality that has not yet been merged into upstream GHC. Aside from the
GHC 'deriving' extensions mentioned above, 'deriving-compat' also permits
deriving instances of classes in the 'Data.Functor.Classes' module, covering
the 'Eq1', 'Eq2', 'Ord1', 'Ord2', 'Read1', 'Read2', 'Show1', and 'Show2'
classes. This extra functionality is outside of the main scope of
'deriving-compat', as it does not backport extensions that exist in today's
GHC. Nevertheless, the underlying Template Haskell machinery needed to derive
'Eq' and friends extends very naturally to 'Eq1' and friends, so this extra
functionality is included in 'deriving-compat' as a convenience.
Note that some recent GHC typeclasses/extensions are not covered by this
package:
* 'DeriveDataTypeable'
* 'DeriveGeneric', which was introducted in GHC 7.2 for deriving 'Generic'
instances, and modified in GHC 7.6 to allow derivation of 'Generic1' instances.
Use 'Generics.Deriving.TH' from
'<http://hackage.haskell.org/package/generic-deriving generic-deriving>' to
derive 'Generic(1)' using Template Haskell.
* 'DeriveLift', which was introduced in GHC 8.0 for deriving 'Lift' instances.
Use 'Language.Haskell.TH.Lift' from
'<http://hackage.haskell.org/package/th-lift th-lift>' to derive 'Lift' using
Template Haskell.
* The 'Bifunctor' typeclass, which was introduced in GHC 7.10, as well as the
'Bifoldable' and 'Bitraversable' typeclasses, which were introduced in GHC 8.2.
Use 'Data.Bifunctor.TH' from '<http://hackage.haskell.org/package/bifunctors
bifunctors>' to derive these typeclasses using Template Haskell. |
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