In cases where a classification needs to be based on a result that has been reduced to a scalar, \ref{_cmatch_to-scalar_} does not solve the whole problem: for this, \ref{_classify-scalar_} may be used. In addition to performing the action of the former (if {\tt @yields} is provided), the resulting classification itself will match on the scalar result. While this is not strictly necessary---the predicate itself is already scalar---this is important for systems or templates that derive the classification result from the name of the classification. The vector analog to \ref{_classify-scalar_} is \ref{_classify-vector_}. The results are undefined if the classification would have otherwise yielded a scalar value (that is, do not use this to force a scalar into a vector). It may work in an intuitive way, but it's not designed to. \ref{_vector-to-class_} converts a vector into a classification.