R/frag.R

In xmlwriter: Fast and Elegant XML Generation

#' Create a frag xml_fragment
#'
#' Create a `frag` xml_fragment, that allows for multiple elements and nested
#' `frag`s.
#' @inheritParams xml_fragment
#' @export
#' @param .attr a list of attributes to add to the parent of the fragment
#' @return an [xml_fragment()] object
#' @example example/xml_fragment.R
#' @family xml_fragment
frag <- function(..., .attr = NULL){
  rcpp_frag(list(...), as.list(.attr))
}

# frag <- function(..., .attr = NULL){
#   n <- list(...)
#   is_list <- sapply(n, is.list)
#
#   # turn all none-lists into text nodes
#   if (length(n) > 0){
#     no_name <- if (is.null(names(n))) {TRUE} else {names(n) == ""}
#
#     n[is_list] <- lapply(n[is_list], unclass)
#     n[!is_list] <- lapply(n[!is_list], .text)
#     n[(!is_list) & no_name] <- lapply(n[(!is_list) & no_name], as.character)
#
#     # check for unnamed elements
#     if (any(no_name & is_list)) {
#       stop("unnamed elements are not allowed in xml fragments")
#     }
#   }
#
#   .attr <- lapply(.attr, as.character)
#   # TODO improve on the attributes, replace names with ".names" etc.
#   attributes(n) <- c(attributes(n), .attr)
#   class(n) <- "xml_fragment"
#   n
# }