add paren_brace_linter (#380)

* cp R/equals_na_lintr.R R/paren_brace_linter.R

* cp tests/testthat/test-equals_na_linter.R tests/testthat/test-paren_brace_linter.R

* add paren_brace_linter; closes #242

* document

* add paren_brace_linter to NEWS.md and README.md

* tweak paren_brace_linter docs

* add paren_brace_linter to default_linters

* improve NEWS entry for paren_brace_linter

DESCRIPTION

@@ -70,6 +70,7 @@ Collate:
     'no_tab_linter.R'
     'object_usage_linter.R'
     'open_curly_linter.R'
+    'paren_brace_linter.R'
     'path_linters.R'
     'pipe_continuation_linter.R'
     'semicolon_terminator_linter.R'

NAMESPACE

@@ -44,6 +44,7 @@ export(object_length_linter)
 export(object_name_linter)
 export(object_usage_linter)
 export(open_curly_linter)
+export(paren_brace_linter)
 export(pipe_continuation_linter)
 export(semicolon_terminator_linter)
 export(seq_linter)

NEWS.md

@@ -1,4 +1,5 @@
 # lintr 1.0.3.9000 # 
+* Added the new `paren_brace_linter()` to the default linters; it checks that there is a space between right parenthesis and an opening curly brace (@bfgray3, #242).
 * Now lintr only tries to generate comments if running in wercker or travis CI (#166)
 * Top level calls that contain function definitions are not properly ignored by
   the object usage linter (#26).

R/paren_brace_linter.R

@@ -0,0 +1,39 @@
+#' @describeIn linters check that there is a space between right
+#' parenthesis and an opening curly brace.
+#' @export
+paren_brace_linter <- function(source_file) {
+  all_matches <- re_matches(
+    source_file[["lines"]],
+    rex("){"),
+    locations = TRUE,
+    global = TRUE
+  )
+  line_numbers <- as.integer(names(source_file[["lines"]]))
+
+  Map(
+    function(line_matches, line_number) {
+      lapply(
+        split(line_matches, seq_len(nrow(line_matches))),
+        function(.match) {
+          start <- .match[["start"]]
+          if (is.na(start)) {
+            return()
+          }
+          end <- .match[["end"]]
+          Lint(
+            filename = source_file[["filename"]],
+            line_number = line_number,
+            column_number = start,
+            type = "style",
+            message = "There should be a space between right parenthesis and an opening curly brace.",
+            line = source_file[["lines"]][[as.character(line_number)]],
+            ranges = list(c(start, end)),
+            linter = "paren_brace_linter"
+          )
+        }
+      )
+    },
+    all_matches,
+    line_numbers
+  )
+}

R/zzz.R

@@ -99,6 +99,7 @@ default_linters <- with_defaults(default = list(),
   object_name_linter("snake_case"),
   object_usage_linter,
   open_curly_linter(),
+  paren_brace_linter,
   pipe_continuation_linter,
   single_quotes_linter,
   spaces_inside_linter,

README.md

@@ -55,6 +55,7 @@ If you need a bit automatic help for re-styling your code, have a look at [the `
   or UPPERCASE.
 * `open_curly_linter`: check that opening curly braces are never on their own
   line and are always followed by a newline.
+* `paren_brace_linter`: check that there is a space between right parenthesis and an opening curly brace.
 * `semicolon_terminator_linter`: check that no semicolons terminate statements.
 * `seq_linter`: check for `1:length(...)`, `1:nrow(...)`, `1:ncol(...)`,
   `1:NROW(...)`, and `1:NCOL(...)` expressions. These often cause bugs when the

tests/testthat/test-paren_brace_linter.R

@@ -0,0 +1,21 @@
+context("paren_brace_linter")
+
+test_that("returns the correct linting", {
+  msg <- rex("There should be a space between right parenthesis and an opening curly brace.")
+
+  expect_lint("blah", NULL, paren_brace_linter)
+  expect_lint("blah <- function() {}", NULL, paren_brace_linter)
+  expect_lint("blah <- function() {\n}", NULL, paren_brace_linter)
+
+  expect_lint(
+    "blah <- function(){}",
+    msg,
+    paren_brace_linter
+  )
+
+  expect_lint(
+    "\nblah <- function(){\n\n\n}",
+    msg,
+    paren_brace_linter
+  )
+})