Function: c-ts-common-comment-indent-new-line

c-ts-common-comment-indent-new-line is a byte-compiled function defined in c-ts-common.el.gz.

Signature

(c-ts-common-comment-indent-new-line &optional SOFT)

Documentation

Break line at point and indent, continuing comment if within one.

This is like comment-indent-new-line, but specialized for C-style // and /* */ comments. SOFT works the same as in comment-indent-new-line.

Source Code

;; Defined in /usr/src/emacs/lisp/progmodes/c-ts-common.el.gz
(defun c-ts-common-comment-indent-new-line (&optional soft)
  "Break line at point and indent, continuing comment if within one.

This is like `comment-indent-new-line', but specialized for C-style //
and /* */ comments.  SOFT works the same as in
`comment-indent-new-line'."
  ;; I want to experiment with explicitly listing out all each cases and
  ;; handle them separately, as opposed to fiddling with `comment-start'
  ;; and friends.  This will have more duplicate code and will be less
  ;; generic, but in the same time might save us from writing cryptic
  ;; code to handle all sorts of edge cases.
  ;;
  ;; For this command, let's try to make it basic: if the current line
  ;; is a // comment, insert a newline and a // prefix; if the current
  ;; line is in a /* comment, insert a newline and a * prefix.  No
  ;; auto-fill or other smart features.
  (let ((insert-line-break
         (lambda ()
	   (delete-horizontal-space)
	   (if soft
	       (insert-and-inherit ?\n)
	     (newline 1)))))
    (cond
     ;; Line starts with //, or ///, or ////...
     ;; Or //! (used in rust).
     ((save-excursion
        (beginning-of-line)
        (re-search-forward
         (rx "//" (group (* (any "/!")) (* " ")))
         (line-end-position)
         t nil))
      (let ((offset (- (match-beginning 0) (line-beginning-position)))
            (whitespaces (match-string 1)))
        (funcall insert-line-break)
        (delete-region (line-beginning-position) (point))
        (insert (make-string offset ?\s) "//" whitespaces)))

     ;; Line starts with /* or /**.
     ((save-excursion
        (beginning-of-line)
        (re-search-forward
         (rx "/*" (group (? "*") (* " ")))
         (line-end-position)
         t nil))
      (let ((offset (- (match-beginning 0) (line-beginning-position)))
            (whitespace-and-star-len (length (match-string 1))))
        (funcall insert-line-break)
        (delete-region (line-beginning-position) (point))
        (insert
         (make-string offset ?\s)
         " *"
         (make-string whitespace-and-star-len ?\s))))

     ;; Line starts with *.
     ((save-excursion
        (beginning-of-line)
        (looking-at (rx (group (* " ") (any "*|") (* " ")))))
      (let ((prefix (match-string 1)))
        (funcall insert-line-break)
        (delete-region (line-beginning-position) (point))
        (insert prefix)))

     ;; Line starts with whitespaces or no space.  This is basically the
     ;; default case since (rx (* " ")) matches anything.
     ((save-excursion
        (beginning-of-line)
        (looking-at (rx (* " "))))
      (let ((whitespaces (match-string 0)))
        (funcall insert-line-break)
        (delete-region (line-beginning-position) (point))
        (insert whitespaces))))))