Functions not objects (#557)

* Option to control whether undesirable function names can appear as symbol

Closes #556

* Use inlined source

* Simplify

* Add expectation

* Remove examples

* Make test more concise

* operator spacing

Co-authored-by: AshesITR <alexander.rosenstock@web.de>
Co-authored-by: Michael Chirico <michaelchirico4@gmail.com>

R/undesirable_function_linter.R

@@ -1,12 +1,22 @@
-#' @describeIn linters  Report the use of undesirable functions, e.g. \code{return}, \code{options},
-#'                      or \code{sapply} and suggest an alternative.
-#' @param fun  Named character vector, where the names are the names of the undesirable functions,
-#'             and the values are the text for the alternative function to use (or \code{NA}).
+#' @describeIn linters Report the use of undesirable functions, e.g.
+#'   \code{return}, \code{options}, or \code{sapply} and suggest an alternative.
+#' @param fun Named character vector, where the names are the names of the
+#'   undesirable functions, and the values are the text for the alternative
+#'   function to use (or \code{NA}).
+#' @param symbol_is_undesirable Whether to consider the use of an undesirable
+#'   function name as a symbol undesirable or not.
 #' @export
-undesirable_function_linter <- function(fun=default_undesirable_functions) {
+undesirable_function_linter <- function(fun = default_undesirable_functions,
+                                        symbol_is_undesirable = TRUE) {
+  stopifnot(is.logical(symbol_is_undesirable))
   function(source_file) {
+    if (symbol_is_undesirable) {
+      vals <- c("SYMBOL_FUNCTION_CALL", "SYMBOL")
+    } else {
+      vals <- "SYMBOL_FUNCTION_CALL"
+    }
     lapply(
-      ids_with_token(source_file, c("SYMBOL_FUNCTION_CALL", "SYMBOL"), fun=`%in%`),
+      ids_with_token(source_file, vals, fun = `%in%`),
       function(id) {
         token <- with_id(source_file, id)
         fun_name <- token[["text"]]

tests/testthat/test-undesirable_function_linter.R

@@ -16,3 +16,12 @@ test_that("linter returns correct linting", {
               ),
               linter)
 })
+
+test_that("it's possible to NOT lint symbols", {
+  linter <- undesirable_function_linter(
+    fun = c("dir" = NA, "log10" = "use log()"),
+    symbol_is_undesirable = FALSE
+  )
+  expect_lint("dir <- 'path/to/a/directory'", NULL, linter)
+  expect_lint("lapply(x, log10)", NULL, linter)
+})