refactor function_left_parentheses_linter() to XPath

DESCRIPTION

@@ -85,7 +85,7 @@ Collate:
     'extract.R'
     'extraction_operator_linter.R'
     'fixed_regex_linter.R'
-    'function_left_parentheses.R'
+    'function_left_parentheses_linter.R'
     'get_source_expressions.R'
     'ids_with_token.R'
     'ifelse_censor_linter.R'

R/function_left_parentheses_linter.R

@@ -0,0 +1,32 @@
+#' Function left parentheses linter
+#'
+#' Check that all left parentheses in a function call do not have spaces before them.
+#'
+#' @evalRd rd_tags("function_left_parentheses_linter")
+#' @seealso
+#'   [linters] for a complete list of linters available in lintr. \cr
+#'   <https://style.tidyverse.org/syntax.html#parentheses>
+#' @export
+function_left_parentheses_linter <- function() { # nolint: object_length.
+  xpath <- "
+    //FUNCTION[@col2 != following-sibling::OP-LEFT-PAREN/@col1 - 1] |
+    //expr[SYMBOL_FUNCTION_CALL and @col2 != following-sibling::OP-LEFT-PAREN/@col1 - 1]
+  "
+
+  Linter(function(source_expression) {
+    if (!is_lint_level(source_expression, "expression")) {
+      return(list())
+    }
+
+    xml <- source_expression$xml_parsed_content
+    bad_exprs <- xml2::xml_find_all(xml, xpath)
+
+    xml_nodes_to_lints(
+      bad_exprs,
+      source_expression = source_expression,
+      lint_message = "Remove spaces before the left parenthesis in a function call.",
+      range_start_xpath = "number(./@col2 + 1)", # start after function / fun
+      range_end_xpath = "number(./following-sibling::OP-LEFT-PAREN/@col1 - 1)" # end before (
+    )
+  })
+}

tests/testthat/test-function_left_parentheses_linter.R

@@ -27,4 +27,15 @@ test_that("returns the correct linting", {
   expect_lint("base::print(blah, f (1))", msg, linter)
   expect_lint("`+` (1, 1)", msg, linter)
   expect_lint("test <- function (x) { }", msg, linter)
+
+  expect_lint(
+    "blah  (1)",
+    list(message = msg, column_number = 5L, ranges = list(c(5L, 6L))),
+    linter
+  )
+  expect_lint(
+    "test <- function  (x) { }",
+    list(message = msg, column_number = 17L, ranges = list(c(17L, 18L))),
+    linter
+  )
 })