[nongnu] elpa/lua-mode 8b9d895 311/468: Fix comments being spilled into the code (issue #25)

[Philip Kaludercic]

branch: elpa/lua-mode
commit 8b9d895b4a5672377d7cc3ff80f0a8555267c2b9
Author: immerrr <immerrr+lua@gmail.com>
Commit: immerrr <immerrr+lua@gmail.com>

    Fix comments being spilled into the code (issue #25)
---
 lua-mode.el       | 23 +++++++++++++++++++++++
 test/test-fill.el | 40 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 63 insertions(+)

diff --git a/lua-mode.el b/lua-mode.el
index 6684c12..2fd79e6 100644
--- a/lua-mode.el
+++ b/lua-mode.el
@@ -731,6 +731,7 @@ Groups 6-9 can be used in any of argument regexps."
   (lua--setq-local comment-start                  lua-comment-start)
   (lua--setq-local comment-start-skip             lua-comment-start-skip)
   (lua--setq-local comment-use-syntax             t)
+  (lua--setq-local fill-paragraph-function        #'lua--fill-paragraph)
   (with-no-warnings
     (lua--setq-local comment-use-global-state     t))
   (lua--setq-local imenu-generic-expression       lua-imenu-generic-expression)
@@ -776,6 +777,28 @@ Groups 6-9 can be used in any of argument regexps."
 
 ;; private functions
 
+(defun lua--fill-paragraph (&optional justify region)
+  ;; Implementation of forward-paragraph for filling.
+  ;;
+  ;; This function works around a corner case in the following situations:
+  ;;
+  ;;     <>
+  ;;     -- some very long comment ....
+  ;;     some_code_right_after_the_comment
+  ;;
+  ;; If point is at the beginning of the comment line, fill paragraph code
+  ;; would have gone for comment-based filling and done the right thing, but it
+  ;; does not find a comment at the beginning of the empty line before the
+  ;; comment and falls back to text-based filling ignoring comment-start and
+  ;; spilling the comment into the code.
+  (while (and (not (eobp))
+              (progn (move-to-left-margin)
+                     (looking-at paragraph-separate)))
+    (forward-line 1))
+  (let ((fill-paragraph-handle-comment t))
+    (fill-paragraph justify region)))
+
+
 (defun lua-prefix-key-update-bindings ()
   (let (old-cons)
     (if (eq lua-prefix-mode-map (keymap-parent lua-mode-map))
diff --git a/test/test-fill.el b/test/test-fill.el
new file mode 100644
index 0000000..8b93d10
--- /dev/null
+++ b/test/test-fill.el
@@ -0,0 +1,40 @@
+;; -*- flycheck-disabled-checkers: (emacs-lisp-checkdoc) -*-
+(load (concat (file-name-directory (or load-file-name (buffer-file-name)
+                                       default-directory))
+              "utils.el") nil 'nomessage 'nosuffix)
+
+
+
+(defun expect-filled-as (strs etalon)
+  (expect
+   (lua-buffer-strs
+    (let ((fill-column 10))
+      (lua-insert-goto-<>
+       strs)
+      (execute-kbd-macro (kbd "M-q"))))
+   :to-equal
+   etalon))
+
+
+
+(describe "Test fill-paragraph"
+  (it "filling single-line comment"
+    (expect-filled-as '("<>-- foo bar baz qux")
+                      '("-- foo bar"
+                        "-- baz qux")))
+  (it "filling comment after code"
+    (expect-filled-as '("<>foo -- bar baz")
+                      '("foo -- bar"
+                        "    -- baz")))
+  (xit "filling multiline comment"
+    (expect-filled-as '("<>--[[ foo bar baz ]]")
+                      '("--[[ foo bar"
+                        "     baz ]]")))
+  (it "does not spill comments into code (issue #25)"
+    (expect-filled-as '("<>"
+                        "-- foo bar baz qux"
+                        "foo_func()")
+                      '(""
+                        "-- foo bar"
+                        "-- baz qux"
+                        "foo_func()"))))