sprinkle comments

Author: teunbrand

R/aes.R

@@ -130,6 +130,7 @@ new_aesthetic <- function(x, env = globalenv()) {
   x
 }
 
+# TODO: remove `local()` when S7 has fixed S7/#390
 #' @export
 local({
   S7::method(print, class_mapping) <- function(x, ...) {

R/plot-build.R

@@ -26,6 +26,7 @@
 #' @keywords internal
 #' @export
 ggplot_build <- function(plot, ...) {
+  # TODO: Swap to S7 generic once S7/#543 is resolved
   env <- try_prop(plot, "plot_env")
   if (!is.null(env)) {
     attach_plot_env(env)
@@ -199,6 +200,7 @@ layer_grob <- get_layer_grob
 #' @param data plot data generated by [ggplot_build()]
 #' @export
 ggplot_gtable <- function(data) {
+  # TODO: Swap to S7 generic once S7/#543 is resolved
   attach_plot_env(data@plot@plot_env)
   UseMethod("ggplot_gtable")
 }

R/theme-elements.R

@@ -466,6 +466,7 @@ element_render <- function(theme, element, ..., name = NULL) {
 #' @keywords internal
 #' @export
 element_grob <- function(element, ...) {
+  # TODO: Swap to S7 generic once S7/#543 is resolved
   UseMethod("element_grob")
 }