{-| Derives an instance of @Monoid@. It uses the product construction of monoids. @mappend@ on two different constructors is undefined. -} module Data.Derive.Monoid(makeMonoid) where {- import Data.Monoid hiding (First) example :: Sample instance Monoid a => Monoid (Sample a) where mempty = head [First, Second (const mempty 1) (const mempty 2), Third (const mempty 1)] mappend (First) (First) = First mappend (Second x1 x2) (Second y1 y2) = Second (mappend x1 y1) (mappend x2 y2) mappend (Third x1) (Third y1) = Third (mappend x1 y1) mappend _ _ | length [First{},Second{},Third{}] > 1 = error "Monoid.mappend: Different constructors for Sample" -} -- GENERATED START import Data.Derive.DSL.DSL import Data.Derive.Internal.Derivation makeMonoid :: Derivation makeMonoid = derivationDSL "Monoid" dslMonoid dslMonoid = List [Instance ["Monoid"] "Monoid" (App "Just" (List [List [App "InsDecl" (List [App "()" (List []),App "PatBind" (List [App "()" (List []),App "PVar" (List [App "()" (List []),App "Ident" (List [ App "()" (List []),String "mempty"])]),App "UnGuardedRhs" (List [ App "()" (List []),App "App" (List [App "()" (List []),App "Var" ( List [App "()" (List []),App "UnQual" (List [App "()" (List []), App "Ident" (List [App "()" (List []),String "head"])])]),App "List" (List [App "()" (List []),MapCtor (Application (Concat ( List [List [App "Con" (List [App "()" (List []),App "UnQual" (List [App "()" (List []),App "Ident" (List [App "()" (List []),CtorName ])])])],MapField (App "Paren" (List [App "()" (List []), Application (List [App "Var" (List [App "()" (List []),App "UnQual" (List [App "()" (List []),App "Ident" (List [App "()" ( List []),String "const"])])]),App "Var" (List [App "()" (List []), App "UnQual" (List [App "()" (List []),App "Ident" (List [App "()" (List []),String "mempty"])])]),App "Lit" (List [App "()" (List [] ),App "Int" (List [App "()" (List []),FieldIndex,ShowInt FieldIndex])])])]))])))])])]),App "Nothing" (List [])])]),App "InsDecl" (List [App "()" (List []),App "FunBind" (List [App "()" (List []),Concat (List [MapCtor (App "Match" (List [App "()" (List []),App "Ident" (List [App "()" (List []),String "mappend"]),List [App "PParen" (List [App "()" (List []),App "PApp" (List [App "()" (List []),App "UnQual" (List [App "()" (List []),App "Ident" (List [App "()" (List []),CtorName])]),MapField (App "PVar" (List [App "()" (List []),App "Ident" (List [App "()" (List []),Concat (List [String "x",ShowInt FieldIndex])])]))])]),App "PParen" (List [App "()" (List []),App "PApp" (List [App "()" (List []),App "UnQual" ( List [App "()" (List []),App "Ident" (List [App "()" (List []), CtorName])]),MapField (App "PVar" (List [App "()" (List []),App "Ident" (List [App "()" (List []),Concat (List [String "y",ShowInt FieldIndex])])]))])])],App "UnGuardedRhs" (List [App "()" (List [] ),Application (Concat (List [List [App "Con" (List [App "()" (List []),App "UnQual" (List [App "()" (List []),App "Ident" (List [App "()" (List []),CtorName])])])],MapField (App "Paren" (List [App "()" (List []),Application (List [App "Var" (List [App "()" (List []),App "UnQual" (List [App "()" (List []),App "Ident" (List [App "()" (List []),String "mappend"])])]),App "Var" (List [App "()" ( List []),App "UnQual" (List [App "()" (List []),App "Ident" (List [App "()" (List []),Concat (List [String "x",ShowInt FieldIndex])] )])]),App "Var" (List [App "()" (List []),App "UnQual" (List [App "()" (List []),App "Ident" (List [App "()" (List []),Concat (List [String "y",ShowInt FieldIndex])])])])])]))]))]),App "Nothing" ( List [])])),List [App "Match" (List [App "()" (List []),App "Ident" (List [App "()" (List []),String "mappend"]),List [App "PWildCard" (List [App "()" (List [])]),App "PWildCard" (List [App "()" (List [])])],App "GuardedRhss" (List [App "()" (List []),List [App "GuardedRhs" (List [App "()" (List []),List [App "Qualifier" (List [App "()" (List []),App "InfixApp" (List [App "()" (List []) ,App "App" (List [App "()" (List []),App "Var" (List [App "()" ( List []),App "UnQual" (List [App "()" (List []),App "Ident" (List [App "()" (List []),String "length"])])]),App "List" (List [App "()" (List []),MapCtor (App "RecConstr" (List [App "()" (List []), App "UnQual" (List [App "()" (List []),App "Ident" (List [App "()" (List []),CtorName])]),List []]))])]),App "QVarOp" (List [App "()" (List []),App "UnQual" (List [App "()" (List []),App "Symbol" ( List [App "()" (List []),String ">"])])]),App "Lit" (List [App "()" (List []),App "Int" (List [App "()" (List []),Int 1,ShowInt ( Int 1)])])])])],App "App" (List [App "()" (List []),App "Var" ( List [App "()" (List []),App "UnQual" (List [App "()" (List []), App "Ident" (List [App "()" (List []),String "error"])])]),App "Lit" (List [App "()" (List []),App "String" (List [App "()" (List []),Concat (List [String "Monoid.mappend: Different constructors for ",DataName]),Concat ( List [String "Monoid.mappend: Different constructors for ", DataName])])])])])]]),App "Nothing" (List [])])]])])])]]))] -- GENERATED STOP