Add cross argument to num_range() (#362)

And use tidyverse recycling rules if `FALSE`

NEWS.md

@@ -1,8 +1,12 @@
 # tidyselect (development version)
 
+* `num_range()` now recycles its arguments using tidyverse rules (#355).
+  In addition, it gains a `cross` argument that allows you to take the
+  cartesian product of these arguments instead.
+
 * `eval_select(allow_empty = FALSE)` gains a new argument to yield a better error
   message in case of empty selection (@olivroy, #327)
-  
+
 * `eval_select()` and `eval_relocate()` gain a new `error_arg` argument that can be specified to throw a better error message when `allow_empty = FALSE`.
 
 * `eval_select()` and `eval_relocate()` throw a classed error message when `allow_empty = FALSE` (@olivroy, #347).
@@ -45,17 +49,17 @@
 
   * `any_of()` generates a more informative error if you supply too many
     arguments (#241).
-  
-  * `all_of()` (like `any_of()`) returns an integer vector to make it easier 
-    to combine in functions (#270, #294). It also fails when it can't find 
+
+  * `all_of()` (like `any_of()`) returns an integer vector to make it easier
+    to combine in functions (#270, #294). It also fails when it can't find
     variables even when `strict = FALSE`.
-  
+
   * `matches()` recognises and correctly uses stringr pattern objects
     (`stringr::regex()`, `stringr::fixed()`, etc) (#238). It also now
     works with named vectors (#250).
-  
+
   * `num_range()` gains a `suffix` argument (#229).
-  
+
   * `where()` is now exported, like all other select helpers (#201),
     and gives more informative errors (#236).
 
@@ -65,27 +69,27 @@
 * `eval_select()` always returns a named vector, even when renaming is not
   permitted (#220).
 
-* `eval_select()` and `eval_relocate()` gain new `allow_empty` argument which 
+* `eval_select()` and `eval_relocate()` gain new `allow_empty` argument which
   makes it possible to forbid empty selections with `allow_empty = FALSE` (#252).
 
 * `eval_select(allow_rename = FALSE)` no longer fails with empty
-  selections (#221, @eutwt) or with predicate functions (#225). It now properly 
+  selections (#221, @eutwt) or with predicate functions (#225). It now properly
   fails with partial renaming (#305).
 
 * `peek_var()` error now generates hyperlink to docs with recent RStudio (#289).
 
 * `vars_pull()` generates more informative error messages (#234, #258, #318)
   and gains `error_call` and `error_arg` arguments.
 
-* Errors produced by tidyselect should now be more informative. Evaluation 
-  errors are now chained, with the child error call is set to the `error_call` 
-  argument of `eval_select()` and `eval_rename()`. We've also improved 
-  backtraces of base errors, and done better at propagating the root 
+* Errors produced by tidyselect should now be more informative. Evaluation
+  errors are now chained, with the child error call is set to the `error_call`
+  argument of `eval_select()` and `eval_rename()`. We've also improved
+  backtraces of base errors, and done better at propagating the root
   `error_call` to vctrs input checkers.
 
 * `tidyselect_verbosity` is no longer used; deprecation messaging is now
   controlled by `lifecycle_verbosity` like all other packages (#317).
-  
+
 # tidyselect 1.1.2
 
 * Fix for CRAN checks.

R/helpers-pattern.R

@@ -174,14 +174,32 @@ matches <- function(match,
 #' @param range A sequence of integers, like `1:5`.
 #' @param width Optionally, the "width" of the numeric range. For example,
 #'   a range of 2 gives "01", a range of three "001", etc.
+#' @inheritParams rlang::args_dots_empty
+#' @param cross Whether to take the cartesian product of `prefix`, `range`, and `suffix`.
+#'   If `FALSE`, the default, these arguments are recycled using [tidyverse rules][vctrs::vector_recycling_rules].
 #' @export
 num_range <- function(prefix,
                       range,
                       suffix = "",
                       width = NULL,
+                      ...,
+                      cross = FALSE,
                       vars = NULL) {
+  check_dots_empty()
+  check_bool(cross)
+  check_number_whole(width, allow_null = TRUE)
+
   vars <- vars %||% peek_vars(fn = "num_range")
 
+  if (cross) {
+    args <- vctrs::vec_expand_grid(prefix = prefix, range = range, suffix = suffix, .error_call = current_env())
+  } else {
+    args <- vctrs::vec_recycle_common(prefix = prefix, range = range, suffix = suffix)
+  }
+  prefix <- args$prefix
+  range <- args$range
+  suffix <- args$suffix
+
   if (!is_null(width)) {
     range <- sprintf(paste0("%0", width, "d"), range)
   }