as_name
(Package: lazyeval) :
Coerce an object to a name or call.
These are a S3 generics with built-in methods for names, calls, formuals, and strings. The distinction between a name and a call is particularly important when coercing from a string. Coercing to a call will parse the string, coercing to a name will create a (potentially) non-syntactic name.
f_rhs
(Package: lazyeval) :
Get/set formula components.
f_rhs extracts the righthand side, f_lhs extracts the lefthand side, and f_env extracts the environment. All functions throw an error if f is not a formula.
f_eval_rhs evaluates the RHS of a formula and f_eval_lhs evaluates the LHS. f_eval is a shortcut for f_eval_rhs since that is what you most commonly need.