New quotes_linter() to replace single_quotes_linter()

DESCRIPTION

@@ -139,6 +139,7 @@ Collate:
     'path_utils.R'
     'pipe_call_linter.R'
     'pipe_continuation_linter.R'
+    'quotes_linter.R'
     'redundant_equals_linter.R'
     'redundant_ifelse_linter.R'
     'regex_subset_linter.R'
@@ -147,7 +148,6 @@ Collate:
     'seq_linter.R'
     'settings.R'
     'settings_utils.R'
-    'single_quotes_linter.R'
     'sort_linter.R'
     'spaces_inside_linter.R'
     'spaces_left_parentheses_linter.R'

NAMESPACE

@@ -103,6 +103,7 @@ export(paren_brace_linter)
 export(paste_linter)
 export(pipe_call_linter)
 export(pipe_continuation_linter)
+export(quotes_linter)
 export(redundant_equals_linter)
 export(redundant_ifelse_linter)
 export(regex_subset_linter)

NEWS.md

@@ -1,5 +1,10 @@
 # lintr (development version)
 
+## Deprecations
+
+* `single_quotes_linter()` is deprecated in favor of the more generalizable `quotes_linter()` (#1729, @MichaelChirico).
+* `unneeded_concatentation_linter()` is deprecated in favor of `unnecessary_concatenation_linter()` for naming consistency (#1707, @IndrajeetPatil).
+
 ## Bug fixes
 
 * `fixed_regex_linter()` is more robust to errors stemming from unrecognized escapes (#1545, #1845, @IndrajeetPatil).
@@ -44,14 +49,14 @@
   the style guide on handling this case awaits clarification: https://github.com/tidyverse/style/issues/191.
   (#1346, @MichaelChirico)
 
-* The new `indentation_linter()` is part of the default linters. See "New linters" for more details.
-
-* For naming consistency, `unneeded_concatenation_linter()` has been deprecated in favor of
-  `unnecessary_concatenation_linter()` (#1797, @IndrajeetPatil).
-
 * `undesirable_function_linter()` and `undesirable_operator_linter()` now produce an error 
   if empty vector of undesirable functions or operators is provided (#1867, @IndrajeetPatil).
 
+* New linters which are also included as defaults (see "New linters" for more details):
+   + `indentation_linter()`
+   + `quotes_linter()`
+   + `unnecessary_concatenation_linter()`
+
 ## New and improved features
 
 * New `get_r_string()` helper to get the R-equivalent value of a string, especially useful for R-4-style raw strings.
@@ -131,6 +136,11 @@
 
 * `implicit_assignment_linter()` for checking implicit assignments in function calls (@IndrajeetPatil and @AshesITR, #1777).
 
+* `quotes_linter()` is a generalized version of (now deprecated) `single_quotes_linter()`. It accepts an argument `delimite_char` to specify whether `"` or `'` should be the accepted method for delimiting character literals. The default, `"`, reflects the Tidyverse guide recommendation and matches the behavior of `single_quotes_linter()`.
+* `quotes_linter()` is a generalized version of (now deprecated) `single_quotes_linter()`. It accepts an argument `quote_char` to specify whether `"` or `'` should be the accepted method for quoting character literals. The default, `"`, reflects the Tidyverse style guide recommendation and matches the behavior of `single_quotes_linter()`.
+
+* `unnecessary_concatenation_linter()` is simply `unneeded_concatenation_linter()`, renamed.
+
 ## Notes
 
 * {lintr} now depends on R version 3.5.0, in line with the tidyverse policy for R version compatibility.

R/lintr-deprecated.R

@@ -213,3 +213,16 @@ find_column_fun <- function(content, newline_locs) {
     line_number - newline_locs[matched_line_number]
   }
 }
+
+#' Single quotes linter
+#' @rdname lintr-deprecated
+#' @export
+single_quotes_linter <- function() {
+  lintr_deprecated(
+    old = "single_quotes_linter",
+    new = "quotes_linter",
+    version = "3.1.0",
+    type = "Linter"
+  )
+  quotes_linter()
+}

R/quotes_linter.R

@@ -0,0 +1,90 @@
+#' Character string quote linter
+#'
+#' Check that the desired quote delimiter is used for string constants.
+#'
+#' @param delimiter Which quote delimiter to accept. Defaults to the tidyverse
+#'   default of `"` (double-quoted strings).
+#'
+#' @examples
+#' # will produce lints
+#' lint(
+#'   text = "c('a', 'b')",
+#'   linters = quotes_linter()
+#' )
+#'
+#' # okay
+#' lint(
+#'   text = 'c("a", "b")',
+#'   linters = quotes_linter()
+#' )
+#'
+#' code_lines <- "paste0(x, '\"this is fine\"')"
+#' writeLines(code_lines)
+#' lint(
+#'   text = code_lines,
+#'   linters = quotes_linter()
+#' )
+#'
+#' # okay
+#' lint(
+#'   text = "c('a', 'b')",
+#'   linters = quotes_linter(delimiter = "'")
+#' )
+#'
+#' @evalRd rd_tags("quotes_linter")
+#' @seealso
+#' - [linters] for a complete list of linters available in lintr.
+#' - <https://style.tidyverse.org/syntax.html#character-vectors>
+#' @export
+quotes_linter <- function(delimiter = c('"', "'")) {
+  delimiter <- match.arg(delimiter)
+  if (delimiter == '"') {
+    quote_regex <- rex(
+      start,
+      zero_or_one(character_class("rR")),
+      single_quote,
+      any_non_double_quotes,
+      single_quote,
+      end
+    )
+    lint_message <- "Only use double-quotes." # nolint: object_usage_linter. An apparent codetools bug.
+  } else {
+    quote_regex <- rex(
+      start,
+      zero_or_one(character_class("rR")),
+      double_quote,
+      any_non_single_quotes,
+      double_quote,
+      end
+    )
+    lint_message <- "Only use single-quotes."
+  }
+  Linter(function(source_expression) {
+    if (!is_lint_level(source_expression, "file")) {
+      return(list())
+    }
+
+    content <- source_expression$full_parsed_content
+    str_idx <- which(content$token == "STR_CONST")
+    quote_matches <- which(re_matches(content[str_idx, "text"], quote_regex))
+
+    lapply(
+      quote_matches,
+      function(id) {
+        with(content[str_idx[id], ], {
+          line <- source_expression$file_lines[[line1]]
+          col2 <- if (line1 == line2) col2 else nchar(line)
+          Lint(
+            filename = source_expression$filename,
+            line_number = line1,
+            column_number = col1,
+            type = "style",
+            message = lint_message,
+            line = line,
+            ranges = list(c(col1, col2))
+          )
+        })
+      }
+    )
+  })
+}

R/zzz.R

@@ -29,9 +29,9 @@ default_linters <- modify_defaults(
   object_usage_linter(),
   paren_body_linter(),
   pipe_continuation_linter(),
+  quotes_linter(),
   semicolon_linter(),
   seq_linter(),
-  single_quotes_linter(),
   spaces_inside_linter(),
   spaces_left_parentheses_linter(),
   T_and_F_symbol_linter(),

inst/lintr/linters.csv

@@ -61,14 +61,15 @@ paren_brace_linter,style readability deprecated
 paste_linter,best_practices consistency configurable
 pipe_call_linter,style readability
 pipe_continuation_linter,style readability default
+quotes_linter,style consistency readability default configurable
 redundant_equals_linter,best_practices readability efficiency common_mistakes
 redundant_ifelse_linter,best_practices efficiency consistency configurable
 regex_subset_linter,best_practices efficiency
 routine_registration_linter,best_practices efficiency robustness
 semicolon_linter,style readability default configurable
 semicolon_terminator_linter,style readability deprecated configurable
 seq_linter,robustness efficiency consistency best_practices default
-single_quotes_linter,style consistency readability default
+single_quotes_linter,style consistency readability deprecated
 sort_linter,readability best_practices efficiency
 spaces_inside_linter,style readability default
 spaces_left_parentheses_linter,style readability default