#4173 lambda functions in discrete scales & facets (#4188)

Author: netique

NEWS.md

@@ -126,6 +126,9 @@
 
 * The scale arguments `limits`, `breaks`, `minor_breaks`, `labels`, `rescaler`
   and `oob` now accept purrr style lambda notation (@teunbrand, #4427).
+  
+* `as_labeller()` (and therefore also `labeller()`) now handles functions in
+  purrr-style lambda notation (@netique, #4188).
 
 # ggplot2 3.3.3
 This is a small patch release mainly intended to address changes in R and CRAN.

R/labeller.r

@@ -318,6 +318,8 @@ as_labeller <- function(x, default = label_value, multi_line = TRUE) {
       x(labels)
     } else if (is.function(x)) {
       default(lapply(labels, x))
+    } else if (is.formula(x)) {
+      default(lapply(labels, as_function(x)))
     } else if (is.character(x)) {
       default(lapply(labels, function(label) x[label]))
     } else {