Stock deriving extensions
Contents
DeriveFoldableexample- Using the
stockderiving strategy
The Haskell report specifies that the following classes may appear in a deriving clause: Eq, Ord, Enum, Ix, Bounded, Read, and Show. We call these “stock” derivable classes, which means the classes and rules for deriving them are standard; stock deriving is the standard deriving strategy for standard typeclasses.
The following GHC language extensions make additional classes stock derivable:
| Extension | Derivable typeclasses |
|---|---|
| DeriveFunctor | Functor |
| DeriveFoldable | Foldable |
| DeriveTraversable | Traversable |
| DeriveGeneric | Generic, Generic1 |
| DeriveLift | Lift |
| DeriveDataTypeable | Data |
DeriveTraversable implies DeriveFunctor and DeriveFoldable.