New helper function for knit_print methods

[Puzzled-Face]

The following code fragments are emerging as common features of knit_print methods. helper functions may be appropriate.

Labels for counts of 1 and >1

knit_print.foo <- function(x, ..., label = c("patient", "patients")) {
  assert_character(label, min.len = 1, max.len = 2, any.missing = FALSE)

  if (length(label) == 1) {
    label[2] <- paste0(label[1], "s")
  }
  ....
}

Provide default values for ...

knit_print.foo <- function(x, ...) {
  param <- list(...)
  if (!("col.names" %in% names(param))) {
    param[["col.names"]] <- c("Lower", "Upper", <some label>)
  }
  if (!("caption" %in% names(param))) {
    param[["caption"]] <- <some caption>
  }
  x <- tidy(x)
  param[["x"]] <- x
  rv <- kableExtra::add_header_above(
    do.call(knitr::kable, param),
    c(<some label> = 2, " " = 1)
  )
...
}