Update utilities-tidy-eval.R and use as_label() (#4076)

Close #4063

Author: yutannihilation

NAMESPACE

@@ -143,6 +143,7 @@ S3method(widthDetails,titleGrob)
 S3method(widthDetails,zeroGrob)
 export("%+%")
 export("%+replace%")
+export(":=")
 export(.data)
 export(.pt)
 export(.stroke)
@@ -271,7 +272,9 @@ export(annotation_logticks)
 export(annotation_map)
 export(annotation_raster)
 export(arrow)
+export(as_label)
 export(as_labeller)
+export(as_name)
 export(autolayer)
 export(autoplot)
 export(benchplot)

R/facet-.r

@@ -213,8 +213,8 @@ Facet <- ggproto("Facet", NULL,
 #'   # Let's enquote the named argument `var` to make it auto-quoting:
 #'   var <- enquo(var)
 #'
-#'   # `quo_name()` will create a nice default name:
-#'   nm <- quo_name(var)
+#'   # `as_label()` will create a nice default name:
+#'   nm <- as_label(var)
 #'
 #'   # Now let's unquote everything at the right place. Note that we also
 #'   # unquote `n` just in case the data frame has a column named

R/quick-plot.r

@@ -89,10 +89,10 @@ qplot <- function(x, y, ..., data, facets = NULL, margins = FALSE,
 
 
   if (is.null(xlab)) {
-    xlab <- quo_name(exprs$x)
+    xlab <- as_label(exprs$x)
   }
   if (is.null(ylab)) {
-    ylab <- quo_name(exprs$y)
+    ylab <- as_label(exprs$y)
   }
 
   if (missing(data)) {

R/utilities-tidy-eval.R

@@ -17,6 +17,22 @@
 #'   captured with [enquo()] or [enquos()]:
 #'   \code{expr(mean(!!enquo(arg), na.rm = TRUE))}.
 #'
+#' * \code{\link[rlang]{as_name}()} transforms a quoted variable name
+#'   into a string. Supplying something else than a quoted variable
+#'   name is an error.
+#'
+#'   That's unlike \code{\link[rlang]{as_label}()} which also returns
+#'   a single string but supports any kind of R object as input,
+#'   including quoted function calls and vectors. Its purpose is to
+#'   summarise that object into a single label. That label is often
+#'   suitable as a default name.
+#'
+#'   If you don't know what a quoted expression contains (for instance
+#'   expressions captured with \code{enquo()} could be a variable
+#'   name, a call to a function, or an unquoted constant), then use
+#'   \code{as_label()}. If you know you have quoted a simple variable
+#'   name, or would like to enforce this, use \code{as_name()}.
+#'
 #' To learn more about tidy eval and how to use these tools, visit
 #' \url{https://tidyeval.tidyverse.org} and the
 #' \href{https://adv-r.hadley.nz/metaprogramming.html}{Metaprogramming
@@ -25,12 +41,14 @@
 #' @md
 #' @name tidyeval
 #' @keywords internal
-#' @aliases          quo quos enquo enquos quo_name
-#'                   sym ensym syms ensyms
-#'                   expr exprs enexpr enexprs
-#'                   .data
-#' @export           quo quos enquo enquos quo_name
-#' @export           sym ensym syms ensyms
-#' @export           expr enexpr enexprs
-#' @export           .data
+#' @aliases expr enquo enquos sym syms .data := as_name as_label
+#' @export expr enquo enquos sym syms .data := as_name as_label
+NULL
+
+# For backward-compatibility, keep exporting the old ones
+
+#' @name tidyeval
+#' @keywords internal
+#' @aliases quo_name quo quos enexpr enexprs ensym ensyms
+#' @export quo_name quo quos enexpr enexprs ensym ensyms
 NULL