R/package.R

In gaborcsardi/dynex: Dynamic Manual Page Examples with Roxygen

#' Dynamic examples with roxygen
#'
#' Create dynamic manual page examples, that are commented out if some
#' condition does not hold, e.g. a dependent package is not installed, or
#' the computer is offline.
#'
#' @docType package
#' @name dynex
"_PACKAGE"

#' @export
#' @importFrom roxygen2 roxy_tag_parse tag_examples

roxy_tag_parse.roxy_tag_dynex <- function(x) {
  x <- tag_examples(x)
  mch <- regexpr("^([^\n]*)", x$val, perl = TRUE)
  cond <- substr(x$val, 1, attr(mch,"capture.length"))
  rest <- substr(x$val, attr(mch,"capture.length") + 2L, nchar(x$val))
  restt <- sub("\n+$", "", rest)
  x$val[] <- paste0(
    "\\dontshow{ if (", cond, ") \\{ }\n",
    restt,
    "\\dontshow{ \\} }"
  )
  x
}

#' @export
#' @importFrom roxygen2 roxy_tag_rd rd_section

roxy_tag_rd.roxy_tag_dynex <- function(x, base_path, env) {
  rd_section("examples", x$val)
}