sprinkle notes

Author: teunbrand

R/aes.R

@@ -131,6 +131,7 @@ new_aesthetic <- function(x, env = globalenv()) {
 }
 
 #' @export
+# TODO: should convert to proper S7 method once bug in S7 is resolved
 `print.ggplot2::mapping` <- function(x, ...) {
   cat("Aesthetic mapping: \n")
 
@@ -146,6 +147,7 @@ new_aesthetic <- function(x, env = globalenv()) {
   invisible(x)
 }
 
+# TODO: should convert to proper S7 method once bug in S7 is resolved
 #' @export
 "[.ggplot2::mapping" <- function(x, i, ...) {
   class_mapping(NextMethod())

R/all-classes.R

@@ -1,15 +1,26 @@
+# S3 classes --------------------------------------------------------------
 
-class_gg     <- S7::new_class("gg", abstract = TRUE)
-class_S3_gg  <- S7::new_S3_class("gg")
+# Meta classes:
+# TODO: These should be replaced once R 4.3.0 is the minimum version as `+`
+# dispatch should work as intended.
+class_gg    <- S7::new_class("gg", abstract = TRUE)
+class_S3_gg <- S7::new_S3_class("gg")
+
+# Proper S3 classes we need awareness for
+class_ggproto <- S7::new_S3_class("ggproto")
+class_gtable  <- S7::new_S3_class("gtable")
+
+# The important ggproto classes that we treat as S3 classes in S7 even though
+# they are their own thing.
 class_scale  <- S7::new_S3_class("Scale")
 class_guides <- S7::new_S3_class("Guides")
 class_coord  <- S7::new_S3_class("Coord")
 class_facet  <- S7::new_S3_class("Facet")
 class_layer  <- S7::new_S3_class("Layer")
 class_layout <- S7::new_S3_class("Layout")
 class_scales_list <- S7::new_S3_class("ScalesList")
-class_ggproto <- S7::new_S3_class("ggproto")
-class_gtable <- S7::new_S3_class("gtable")
+
+# User facing classes -----------------------------------------------------
 
 #' The theme class
 #'

R/plot.R

@@ -198,6 +198,7 @@ is.ggplot <- function(x) {
 #'   print(ggplot(mpg, aes(displ, hwy, colour = .data[[colour]])) +
 #'           geom_point())
 #' }
+# TODO: should convert to proper S7 method once bug in S7 is resolved
 `print.ggplot2::ggplot` <- function(x, newpage = is.null(vp), vp = NULL, ...) {
   set_last_plot(x)
   if (newpage) grid.newpage()
@@ -230,6 +231,10 @@ is.ggplot <- function(x) {
 
 S7::method(plot, class_ggplot) <- `print.ggplot2::ggplot`
 
+# The following extractors and subassignment operators are for a smooth
+# transition and should be deprecated in the release cycle after 4.0.0
+# TODO: should convert to proper S7 method once bug in S7 is resolved
+
 #' @export
 `$.ggplot2::gg` <- function(x, i) {
   `[[`(S7::props(x), i)