exporting a previously internal fn (#116)

**What changes are proposed in this pull request?**


**Reference GitHub issue associated with pull request.** _e.g., 'closes
#1'_
closes #39 


--------------------------------------------------------------------------------

Reviewer Checklist (if item does not apply, mark is as complete)

- [ ] Ensure all package dependencies are installed:
`devtools::install_dev_deps()`
- [ ] PR branch has pulled the most recent updates from master branch:
`usethis::pr_merge_main()`
- [ ] If a bug was fixed, a unit test was added.
- [ ] Run `pkgdown::build_site()`. Check the R console for errors, and
review the rendered website.
- [ ] Code coverage is suitable for any new functions/features:
`devtools::test_coverage()`
- [ ] `usethis::use_spell_check()` runs with no spelling errors in
documentation

When the branch is ready to be merged:
- [ ] Update `NEWS.md` with the changes from this pull request under the
heading "`# cards (development version)`". If there is an issue
associated with the pull request, reference it in parentheses at the end
update (see `NEWS.md` for examples).
- [ ] Increment the version number using `usethis::use_version(which =
"dev")`
- [ ] Run `usethis::use_spell_check()` again
- [ ] Approve Pull Request
- [ ] Merge the PR. Please use "Squash and merge".

NAMESPACE

@@ -2,6 +2,7 @@
 
 S3method(print,card)
 export("%>%")
+export(alias_as_fmt_fn)
 export(all_ard_groups)
 export(all_ard_variables)
 export(all_of)

R/apply_statistic_fmt_fn.R

@@ -1,6 +1,7 @@
 #' Apply Formatting Functions
 #'
 #' Apply the formatting functions to each of the raw statistics.
+#' Function aliases are converted to functions using `alias_as_fmt_fn()`.
 #'
 #' @param x (`data.frame`)\cr
 #'   an ARD data frame of class 'card'
@@ -24,14 +25,40 @@ apply_statistic_fmt_fn <- function(x) {
           .data$statistic,
           .data$statistic_fmt_fn,
           function(x, fn) {
-            if (!is.null(fn)) do.call(.convert_alias_to_fmt_fn(fn), args = list(x))
+            if (!is.null(fn)) do.call(alias_as_fmt_fn(fn), args = list(x))
             else NULL
           }
         )
     )
 }
 
-.convert_alias_to_fmt_fn <- function(x, call = caller_env()) {
+
+
+#' Convert Alias to Function
+#'
+#' @description
+#' Accepted aliases are non-negative integers and strings.
+#'
+#' The integers are converted to functions that round the statistics
+#' to the number of decimal places to match the integer.
+#'
+#' The formatting strings come in the form `"xx"`, `"xx.x"`, `"xx.x%"`, etc.
+#' The number of `x`s that appear after the decimal place indicate the number of
+#' decimal places the statistics will be rounded to.
+#' The number of `x`s that appear before the decimal place indicate the leading
+#' spaces that are added to the result.
+#' If the string ends in `"%"`, results are scaled by 100 before rounding.
+#'
+#' @param x a non-negative integer, string alias, or function
+#' @param call call environment for error messaging
+#'
+#' @return a function
+#' @export
+#'
+#' @examples
+#' alias_as_fmt_fn(1)
+#' alias_as_fmt_fn("xx.x")
+alias_as_fmt_fn <- function(x, call = caller_env()) {
   if (is.function(x))
     return(x)
   if (is_integerish(x) && x >= 0L)

_pkgdown.yml

@@ -44,6 +44,7 @@ reference:
       - nest_for_ard
       - default_stat_labels
       - check_ard_structure
+      - alias_as_fmt_fn
   - subtitle: "Wrangle ARD"
     contents:
       - flatten_ard