importexport.RdSurv and ggplot are imported from, respectively, the
survival and ggplot2 packages and are exported from
rms so that the user does not have to attach these packages to do
simple things.
Surv(time, time2, event,
type = c("right", "left", "interval", "counting", "interval2", "mstate"),
origin = 0)
ggplot(data = NULL, mapping = aes(), ..., environment = parent.frame())see documentation in the original packages