RHSForm                 extract right-hand side of a formula
anySpecial              Detect whether there are any 'specials' in a
                        formula term
expandDoubleVerts       Expand terms with "||" notation into separate
                        "|" terms
expandGrpVar            apply
findReTrmClasses        list of specials - taken from enum.R
isNested                Is f1 nested within f2?
mkReTrms                Create list of structures needed for models
                        with random effects
no_specials             Drop 'specials' from a formula
nobars                  Omit terms separated by vertical bars in a
                        formula
subbars                 "Substitute bars"
