BOOST_PROTO_MAX_LOGICAL_ARITY — Controls the maximum number of sub-grammars that proto::or_<> and proto::and_<> accept.
proto::or_<>
proto::and_<>
BOOST_PROTO_MAX_LOGICAL_ARITY
BOOST_PROTO_MAX_LOGICAL_ARITY defaults to 8. It may be set higher or lower. Setting it higher will have a negative effect on compile times.