R/defaults.R

In yonicd/chunky: Rstudio Addin to Wrap Script in Rmarkdown Chunks

# forked from https://github.com/yihui/knitr/blob/master/R/defaults.R
#' @importFrom stats setNames
new_defaults <- function(value = list()) {
  defaults <- value

  get <- function(name, default = FALSE, drop = TRUE, regex=FALSE, ...) {
    if (default) defaults <- value # this is only a local version
    if (missing(name)) {
      defaults
    } else {
      if (drop && length(name) == 1) {
        if (regex) {
          name_grep <- grep(name, names(defaults), value = TRUE, ...)
          stats::setNames(defaults[name_grep], name_grep)
        } else {
          defaults[[name]]
        }
      } else {
        stats::setNames(defaults[name], name)
      }
    }
  }

  set <- function(...) {
    dots <- list(...)
    if (length(dots) == 0) return()
    if (is.null(names(dots)) && length(dots) == 1 && is.list(dots[[1]])) {
      if (length(dots <- dots[[1]]) == 0) {
        return()
      }
    }
    defaults <<- merge(dots)
    invisible(NULL)
  }

  merge <- function(values) merge_list(defaults, values)

  restore <- function(target = value) defaults <<- target

  append <- function(...) {
    dots <- list(...)
    if (length(dots) == 0) return()
    if (is.null(names(dots)) && length(dots) == 1 && is.list(dots[[1]])) {
      if (length(dots <- dots[[1]]) == 0) {
        return()
      }
    }
    dots <- sapply(names(dots), function(x) dots[[x]] <- c(defaults[[x]], dots[[x]]), simplify = FALSE)
    defaults <<- merge(dots)
    invisible(NULL)
  }

  list(get = get, set = set, append = append, merge = merge, restore = restore)
}

#' @title Default and current chunky options
#'
#' @description Options for functions in the chunky package. When running R code, the object \code{chunky_opts}
#' (default options) is not modified by chunk headers (local chunk options are
#' merged with default options), whereas \code{chunky_opts_current} (current options)
#' changes with different chunk headers and it always reflects the options for
#' the current chunk.
#'
#' Normally we set up the global options once in the first code chunk in a
#' document using \code{chunky_opts$set()}, so that all \emph{latter} chunks will
#' use these options. Note the global options set in one chunk will not affect
#' the options in this chunk itself, and that is why we often need to set global
#' options in a separate chunk.
#'
#' Below is a list of default chunk options, retrieved via
#' \code{chunky_opts$get()}:
#'
#' \Sexpr[results=verbatim]{str(chunky::chunky_opts$get())}
# @references Usage: \url{https://yihui.name/knitr/objects/}
#'
#   A list of available options:
#   \url{https://yihui.name/knitr/options/#chunk_options}
#' @note \code{chunky_opts_current} is read-only in the sense that it does nothing if
#'   you call \code{chunky_opts_current$set()}; you can only query the options via
#'   \code{chunky_opts_current$get()}.
#' @export
#' @rdname chunkyOpts
#' @examples chunky_opts$get('name')
chunky_opts <- new_defaults(list(
  basic=FALSE,
  name='chunky',
  counter=TRUE,
  chunk_opts=NULL,
  full_doc=FALSE,
  token='^#{2} -{4}(.*?)-{4+}$'
))

#' @rdname chunkyOpts
#' @export
chunky_opts_current <- new_defaults()

# merge elements of y into x with the same names
merge_list <- function(x, y) {
  x[names(y)] <- y
  x
}