# Pastebin 415esCiO
mkInstanceDeclaration :: String -> Name -> [VarBangType] -> Q [Dec]
mkInstanceDeclaration tagName typeConstr fields = do
  fieldsExps <- fmap ListE $
    forM fields $ \(fieldName, _, _) ->
      [e|($(stringE $ nameBase fieldName), $(varE fieldName) el & $(appTypeE $(varE $ mkName "field") $(strTyLit $ nameBase fieldName)) %~ (fmap) (pack . show))|]
  [d|
    instance Applicative f => Component2 f $(conT typeConstr) where
      tag2 = $(stringE tagName)
      attributes2 $(varP $ mkName "el") = $(pure fieldsExps)
    |]