Better strategy for finding geoms/stats by name

Author: hadley

R/geom-defaults.r

@@ -13,7 +13,7 @@
 #' @rdname update_defaults
 update_geom_defaults <- function(geom, new) {
   if (is.character(geom)) {
-    g <- find_subclass("Geom", geom)
+    g <- find_subclass("Geom", geom, parent.frame())
   } else if (inherits(geom, "Geom")) {
     g <- geom
   } else {
@@ -29,7 +29,7 @@ update_geom_defaults <- function(geom, new) {
 #' @export
 update_stat_defaults <- function(stat, new) {
   if (is.character(stat)) {
-    g <- find_subclass("Stat", stat)
+    g <- find_subclass("Stat", stat, parent.frame())
   } else if (inherits(stat, "Stat")) {
     g <- stat
   } else {

R/layer.r

@@ -87,11 +87,11 @@ layer <- function(geom = NULL, stat = NULL,
   }
 
   if (is.character(geom))
-    geom <- find_subclass("Geom", geom)
+    geom <- find_subclass("Geom", geom, parent.frame())
   if (is.character(stat))
-    stat <- find_subclass("Stat", stat)
+    stat <- find_subclass("Stat", stat, parent.frame())
   if (is.character(position))
-    position <- find_subclass("Position", position)
+    position <- find_subclass("Position", position, parent.frame())
 
   # Special case for na.rm parameter needed by all layers
   if (is.null(params$na.rm)) {
@@ -316,14 +316,13 @@ Layer <- ggproto("Layer", NULL,
 is.layer <- function(x) inherits(x, "Layer")
 
 
-find_subclass <- function(super, class) {
+find_subclass <- function(super, class, env) {
   name <- paste0(super, camelize(class, first = TRUE))
-  if (!exists(name)) {
-    stop("No ", tolower(super), " called ", name, ".", call. = FALSE)
-  }
+  obj <- find_global(name, env = env)
 
-  obj <- get(name)
-  if (!inherits(obj, super)) {
+  if (is.null(name)) {
+    stop("No ", tolower(super), " called ", name, ".", call. = FALSE)
+  } else if (!inherits(obj, super)) {
     stop("Found object is not a ", tolower(super), ".", call. = FALSE)
   }
 

R/utilities-help.r

@@ -1,8 +1,8 @@
 
 rd_aesthetics <- function(type, name) {
   obj <- switch(type,
-    geom = find_subclass("Geom", name),
-    stat = find_subclass("Stat", name)
+    geom = find_subclass("Geom", name, globalenv()),
+    stat = find_subclass("Stat", name, globalenv())
   )
   aes <- rd_aesthetics_item(obj)