--generate-parser
--generate-serializer
--generate-aggregate
--root-element-all
--custom-type envelope=v//envelope_base/envelope.hxx
--custom-parser envelope=envelope_base_pimpl/envelope-pimpl.hxx
--custom-serializer envelope=envelope_base_simpl/envelope-simpl.hxx
--hxx-epilogue #include "body.hxx"