R/z_staticdocs_highlight.R

In hafen/packagedocs: Build Website of Package Documentation

# nolint start
# This file is taken directly from https://github.com/hadley/staticdocs/blob/master/R/highlight.r
# All @export tags were removed as it is only for internal use


#' @importFrom highlight highlight renderer_html formatter_html
src_highlight <- function(text, index) {
  if (str_trim(text) == "") return("")

  expr <- NULL
  try(expr <- getParseData(x = text))
  if (length(expr) == 0) return(text)

  # Custom formatter that adds links to function calls
  formatter <- function(tokens, styles, ...) {
    funcall <- styles == "functioncall"
    for(i in which(funcall)) {
      loc <- find_topic(tokens[i], NULL, index = index)
      if (is.null(loc)) {
        message("Can't find help topic ", tokens[i])
        next
      }
      tokens[i] <- make_link(loc, label = tokens[i])
    }

    formatter_html(tokens, styles, ...)
  }

  renderer <- renderer_html(document = FALSE, formatter = formatter)
  out <- capture.output(highlight(parser.output = expr, renderer = renderer))
  # Drop pre tag
  out <- out[-c(1, length(out))]
  str_c(out, collapse = "\n")
}

# nolint end