From 63f122f101f66f0235094f286cb5f6d86392e49c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ji=C5=99=C3=AD=20Moravec?= <jiri.c.moravec@gmail.com>
Date: Thu, 22 Feb 2024 09:50:18 +1300
Subject: [PATCH] Allows the use = instead of <-
---
R/assignment_linter.R | 15 ++++++++++++---
tests/testthat/test-assignment_linter.R | 8 ++++++++
2 files changed, 20 insertions(+), 3 deletions(-)
diff --git a/R/assignment_linter.R b/R/assignment_linter.R
index da42b51194..fe96dff06d 100644
--- a/R/assignment_linter.R
+++ b/R/assignment_linter.R
@@ -2,6 +2,8 @@
#'
#' Check that `<-` is always used for assignment.
#'
+#' @param allow_equal_assignment Logical, default `FALSE`.
+#' If `TRUE`, `=` instead of `<-` is used for assignment.
#' @param allow_cascading_assign Logical, default `TRUE`.
#' If `FALSE`, [`<<-`][base::assignOps] and `->>` are not allowed.
#' @param allow_right_assign Logical, default `FALSE`. If `TRUE`, `->` and `->>` are allowed.
@@ -70,7 +72,9 @@
#' - <https://style.tidyverse.org/syntax.html#assignment-1>
#' - <https://style.tidyverse.org/pipes.html#assignment-2>
#' @export
-assignment_linter <- function(allow_cascading_assign = TRUE,
+assignment_linter <- function(
+ allow_equal_assignment = FALSE,
+ allow_cascading_assign = TRUE,
allow_right_assign = FALSE,
allow_trailing = TRUE,
allow_pipe_assign = FALSE) {
@@ -88,7 +92,7 @@ assignment_linter <- function(allow_cascading_assign = TRUE,
xpath <- paste(collapse = " | ", c(
# always block = (NB: the parser differentiates EQ_ASSIGN, EQ_SUB, and EQ_FORMALS)
- "//EQ_ASSIGN",
+ if (allow_equal_assignment) "//LEFT_ASSIGN" else "//EQ_ASSIGN",
# -> and ->> are both 'RIGHT_ASSIGN'
if (!allow_right_assign) "//RIGHT_ASSIGN" else if (!allow_cascading_assign) "//RIGHT_ASSIGN[text() = '->>']",
# <-, :=, and <<- are all 'LEFT_ASSIGN'; check the text if blocking <<-.
@@ -108,7 +112,12 @@ assignment_linter <- function(allow_cascading_assign = TRUE,
}
operator <- xml_text(bad_expr)
- lint_message_fmt <- rep("Use <-, not %s, for assignment.", length(operator))
+ lint_message_fmt = rep(
+ paste0("Use ",
+ if (allow_equal_assignment) "=" else "<-",
+ ", not %s, for assignment."),
+ length(operator)
+ )
lint_message_fmt[operator %in% c("<<-", "->>")] <-
"Replace %s by assigning to a specific environment (with assign() or <-) to avoid hard-to-predict behavior."
lint_message_fmt[operator == "%<>%"] <-
diff --git a/tests/testthat/test-assignment_linter.R b/tests/testthat/test-assignment_linter.R
index bae8a048e3..71d008d062 100644
--- a/tests/testthat/test-assignment_linter.R
+++ b/tests/testthat/test-assignment_linter.R
@@ -192,3 +192,11 @@ test_that("multiple lints throw correct messages", {
assignment_linter(allow_cascading_assign = FALSE)
)
})
+
+test_that("equal = instead of <- can be used for assignment", {
+ linter <- assignment_linter(allow_equal_assignment = TRUE)
+ lint_msg <- rex::rex("Use =, not <-, for assignment.")
+
+ expect_lint("blah = 1", NULL, linter)
+ expect_lint("blah <- 1", lint_msg, linter)
+})