Returns a list containing the terms in a given formula
list_rhs.formula(object)list_rhs.formula returns a list of formula terms, with an additional numerical vector attribute "sign" with of the same length, giving the corresponding term's sign as +1 or -1.
formula A formula having a right-hand-side that can be interpretated as a rpm specification.
returns a list containing terms in a given
formula, handling + and - operators and parentheses, and
keeping track of whether a term has a plus or a minus sign.