as.character.formula    Converts a formula to character representation
formula.tools-package   Tools for working with formulas, expressions,
                        calls and other R objects
get.vars-methods        Get variable (names) from various R objects
invert-methods          Invert relative operators
is.cat                  Identify variables by there variable type:
                        categorical or continuous
is.one.sided-methods    is.one.sided, is.two.sided
lhs-methods             Manipulate the component parts of formulas,
                        expressions, calls, name/symbols and list and
                        vectors of such objects.
terms.call              terms method for call object
