BOOST_PROTO_MAX_LOGICAL_ARITY — Controls the maximum number of sub-grammars that proto::or_<> and proto::and_<> accept.
// In header: <boost/proto/proto_fwd.hpp> 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.
