Modulederiving-compat-0.6.8Haskell2010

Data.Enum.Deriving

Exports functions to mechanically derive Enum instances.

Contents

Synopsis

Enum

valuederiveEnum :: Name -> Q [Dec]

Generates an Enum instance declaration for the given data type or data family instance.

valuemakeSucc :: Name -> Q Exp

Generates a lambda expression which behaves like succ (without requiring an Enum instance).

valuemakePred :: Name -> Q Exp

Generates a lambda expression which behaves like pred (without requiring an Enum instance).

valuemakeToEnum :: Name -> Q Exp

Generates a lambda expression which behaves like toEnum (without requiring an Enum instance).

valuemakeFromEnum :: Name -> Q Exp

Generates a lambda expression which behaves like fromEnum (without requiring an Enum instance).

valuemakeEnumFrom :: Name -> Q Exp

Generates a lambda expression which behaves like enumFrom (without requiring an Enum instance).

valuemakeEnumFromThen :: Name -> Q Exp

Generates a lambda expression which behaves like enumFromThen (without requiring an Enum instance).

Be aware of the following potential gotchas:

Type variables of kind * are assumed to have Enum constraints. If this is not desirable, use makeToEnum or one of its cousins.
Generated Enum instances for poly-kinded data family instances are likely to require the use of the TypeInType extension on GHC 8.0, 8.2, or 8.4.