linearise discrete get_labels() logic

Author: teunbrand

R/scale-.R

@@ -1074,47 +1074,38 @@ ScaleDiscrete <- ggproto("ScaleDiscrete", Scale,
       return(NULL)
     }
 
-    if (is.null(self$labels)) {
+    labels <- self$labels
+    if (is.null(labels)) {
       return(NULL)
     }
 
-    if (identical(self$labels, NA)) {
+    if (identical(labels, NA)) {
       cli::cli_abort(
         "Invalid {.arg labels} specification. Use {.code NULL}, not {.code NA}.",
         call = self$call
       )
     }
 
-    if (is.waiver(self$labels)) {
+    if (is.waiver(labels)) {
       if (!is.null(names(breaks))) {
-        return(names(breaks))
-      }
-      if (is.numeric(breaks)) {
+        labels <- names(breaks)
+      } else if (is.numeric(breaks)) {
         # Only format numbers, because on Windows, format messes up encoding
-        format(breaks, justify = "none")
+        labels <- format(breaks, justify = "none")
       } else {
-        as.character(breaks)
+        labels <- as.character(breaks)
       }
-    } else if (is.function(self$labels)) {
-      self$labels(breaks)
-    } else {
-      if (!is.null(names(self$labels))) {
-        # If labels have names, use them to match with breaks
-        labels <- breaks
-
-        map <- match(names(self$labels), labels, nomatch = 0)
-        labels[map] <- self$labels[map != 0]
-        labels
-      } else {
-        labels <- self$labels
+    } else if (is.function(labels)) {
+      labels <- labels(breaks)
+    } else if (!is.null(names(labels))) {
+      # If labels have names, use them to match with breaks
+      map <- match(names(self$labels), breaks, nomatch = 0)
+      labels <- replace(breaks, map, labels[map != 0])
+    } else if (!is.null(attr(breaks, "pos"))) {
+      # Need to ensure that if breaks were dropped, corresponding labels are too
+      labels <- labels[attr(breaks, "pos")]
+    }
 
-        # Need to ensure that if breaks were dropped, corresponding labels are too
-        pos <- attr(breaks, "pos")
-        if (!is.null(pos)) {
-          labels <- labels[pos]
-        }
-        labels
-      }
     }
   },