R/title.R

In hadley/colformat: Coloured Formatting for Columns

style_title <- style_bold

#' Prepare a column title for formatting
#'
#' Call [format()] on the result to render column titles.
#'
#' @param x A character vector of column titles.
#' @inheritParams rlang::args_dots_empty
#' @export
#' @examples
#' format(new_pillar_title(names(trees)))
new_pillar_title <- function(x, ...) {
  "!!!!DEBUG new_pillar_title(`v(x)`)"
  if (!missing(...)) {
    check_dots_empty(action = warn)
  }

  if (is.null(x)) {
    width <- 0L
  } else if (all(is.na(x) | x == "")) {
    width <- 0L
    x <- NULL
  } else {
    width <- get_max_extent(format_title(x, width = Inf))
    stopifnot(!is.na(width))
  }

  ret <- structure(list(x), class = "pillar_title")

  ret <- set_width(ret, width)
  ret <- set_min_width(ret, min(width, get_min_title_width(width)))
  ret
}

get_min_title_width <- function(width) {
  title_chars <- get_pillar_option_min_title_chars()
  if (!is.numeric(title_chars) || length(title_chars) != 1 || title_chars < 0) {
    stop("Option pillar.min_title_chars must be a nonnegative number", call. = FALSE)
  }

  if (is.infinite(title_chars)) {
    return(width)
  }

  # We don't use the ellipsis if we don't truncate, a solution with min()
  # is difficult to make work in all corner cases (and slower too)
  if (width <= title_chars) {
    return(width)
  }
  title_chars + 2L
}

#' @export
format.pillar_title <- function(x, width = NULL, ..., footnote_idx = 0L) {
  title <- x[[1]]
  if (is.null(title)) {
    return(character())
  }

  if (is.null(width)) {
    width <- get_width(x)
  }

  footnote <- (footnote_idx > 0L)
  title <- format_title(title, width, footnote)
  if (footnote) {
    title <- gsub("\u02df$", superdigit(footnote_idx), title)
  }
  style_title(title)
}