Generics.Instant.TH

This module contains Template Haskell code that can be used to automatically generate the boilerplate code for the generic deriving library.

Main generator

deriveAll :: Name -> Q [Dec]

Given the type and the name (as string) for the type to derive, generate the Constructor instances and the Representable instance.

deriveAllL :: [Name] -> Q [Dec]

Same as deriveAll, but taking a list as input.

Individual generators

deriveConstructors :: Name -> Q [Dec]

Given a datatype name, derive datatypes and instances of class Constructor.

deriveRepresentable :: Name -> Q [Dec]

Given the type and the name (as string) for the Representable type synonym to derive, generate the Representable instance.

deriveRep :: Name -> Q [Dec]

Derive only the Rep type synonym. Not needed if deriveRepresentable is used.

Utilities

simplInstance :: Name -> Name -> Name -> Name -> Q [Dec]

Given the names of a generic class, a type to instantiate, a function in the class and the default implementation, generates the code for a basic generic instance.

gadtInstance :: Name -> Name -> Name -> Name -> Q [Dec]

Given the names of a generic class, a GADT type to instantiate, a function in the class and the default implementation, generates the code for a basic generic instance. This is tricky in general because we have to analyze the return types of each of the GADT constructors and give instances accordingly.

genRepName :: Name -> Name

typeVariables :: Info -> [TyVarBndr]

tyVarBndrToName :: TyVarBndr -> Name