;; along with GNU Emacs; see the file COPYING. If not, write to
;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+;;; Commentary:
+
+;; A smart editing mode for C code. It knows a lot about C syntax and tries
+;; to position the curser according to C layout conventions. You can
+;; change the details of the layout style with option variables. Load it
+;; and do M-x describe-mode for details.
+
;;; Code:
(defvar c-mode-abbrev-table nil
(define-key c-mode-map "\ea" 'c-beginning-of-statement)
(define-key c-mode-map "\ee" 'c-end-of-statement)
(define-key c-mode-map "\eq" 'c-fill-paragraph)
+ (define-key c-mode-map "\C-c\C-n" 'c-forward-conditional)
+ (define-key c-mode-map "\C-c\C-p" 'c-backward-conditional)
+ (define-key c-mode-map "\C-c\C-u" 'c-up-conditional)
(define-key c-mode-map "\177" 'backward-delete-char-untabify)
(define-key c-mode-map "\t" 'c-indent-command))
(c-brace-offset . -4)
(c-label-offset . -4)
(c-continued-statement-offset . 4))
- (C++
+ ("C++"
(c-indent-level . 4)
(c-continued-statement-offset . 4)
(c-brace-offset . -4)
(defconst c-tab-always-indent t
"*Non-nil means TAB in C mode should always reindent the current line,
regardless of where in the line point is when the TAB command is used.")
+
+;;; Regular expression used internally to recognize labels in switch
+;;; statements.
+(defconst c-switch-label-regexp "case[ \t'/(]\\|default\\(\\S_\\|'\\)")
+
\f
(defun c-mode ()
"Major mode for editing C code.
(setq comment-column 32)
(make-local-variable 'comment-start-skip)
(setq comment-start-skip "/\\*+ *")
- (make-local-variable 'comment-indent-hook)
- (setq comment-indent-hook 'c-comment-indent)
+ (make-local-variable 'comment-indent-function)
+ (setq comment-indent-function 'c-comment-indent)
(make-local-variable 'parse-sexp-ignore-comments)
(setq parse-sexp-ignore-comments t)
(run-hooks 'c-mode-hook))
;; Check for obvious entry to comment.
(save-excursion
(beginning-of-line)
- (skip-chars-forward " \t")
+ (skip-chars-forward " \t\n")
(and (looking-at comment-start-skip)
(setq comment-start-place (point))))))
(if (or first-line
(eq (calculate-c-indent) t)
;; t if this line contains a comment starter.
(setq first-line
- (save-excursion (beginning-of-line)
- (prog1
- (re-search-forward comment-start-skip
- (save-excursion (end-of-line)
- (point))
- t)
- (setq comment-start-place (point))))))
+ (save-excursion
+ (beginning-of-line)
+ (prog1
+ (re-search-forward comment-start-skip
+ (save-excursion (end-of-line)
+ (point))
+ t)
+ (setq comment-start-place (point))))))
;; Inside a comment: fill one comment paragraph.
(let ((fill-prefix
;; The prefix for each line of this paragraph
(progn (re-search-forward comment-start-skip)
(make-string (current-column) ?\ ))
(if first-line (forward-line 1))
- (buffer-substring (point)
- (progn
- (move-to-column
- (calculate-c-indent-within-comment t)
- t)
- (point))))))
+
+ (let ((line-width (progn (end-of-line) (current-column))))
+ (beginning-of-line)
+ (prog1
+ (buffer-substring
+ (point)
+
+ ;; How shall we decide where the end of the
+ ;; fill-prefix is?
+ ;; calculate-c-indent-within-comment bases its value
+ ;; on the indentation of previous lines; if they're
+ ;; indented specially, it could return a column
+ ;; that's well into the current line's text. So
+ ;; we'll take at most that many space, tab, or *
+ ;; characters, and use that as our fill prefix.
+ (let ((max-prefix-end
+ (progn
+ (move-to-column
+ (calculate-c-indent-within-comment t)
+ t)
+ (point))))
+ (beginning-of-line)
+ (skip-chars-forward " \t*" max-prefix-end)
+ (point)))
+
+ ;; If the comment is only one line followed by a blank
+ ;; line, calling move-to-column above may have added
+ ;; some spaces and tabs to the end of the line; the
+ ;; fill-paragraph function will then delete it and the
+ ;; newline following it, so we'll lose a blank line
+ ;; when we shouldn't. So delete anything
+ ;; move-to-column added to the end of the line. We
+ ;; record the line width instead of the position of the
+ ;; old line end because move-to-column might break a
+ ;; tab into spaces, and the new characters introduced
+ ;; there shouldn't be deleted.
+
+ ;; If you can see a better way to do this, please make
+ ;; the change. This seems very messy to me.
+ (delete-region (progn (move-to-column line-width)
+ (point))
+ (progn (end-of-line) (point))))))))
+
(paragraph-start
;; Lines containing just a comment start or just an end
;; should not be filled into paragraphs they are next to.
- (concat paragraph-start
- "\\|^[ \t]*/\\*[ \t]*$\\|^[ \t]*\\*/[ \t]*$\\|^[^ \t/*]"))
+ (concat
+ paragraph-start
+ "\\|^[ \t]*/\\*[ \t]*$\\|^[ \t]*\\*/[ \t]*$\\|^[ \t/*]*$"))
(paragraph-separate
- (concat paragraph-separate
- "\\|^[ \t]*/\\*[ \t]*$\\|^[ \t]*\\*/[ \t]*$\\|^[^ \t/*]"))
+ (concat
+ paragraph-separate
+ "\\|^[ \t]*/\\*[ \t]*$\\|^[ \t]*\\*/[ \t]*$\\|^[ \t/*]*$"))
(chars-to-delete 0))
(save-restriction
;; Don't fill the comment together with the code following it.
;; given the narrowing) and don't leave it on its own line.
(goto-char (point-max))
(forward-line -1)
- (search-forward "*/")
+ (search-forward "*/" nil 'move)
(beginning-of-line)
(if (looking-at "[ \t]*\\*/")
(delete-indentation)))))
;; So quickly rule out most other uses of colon
;; and do no indentation for them.
(and (eq last-command-char ?:)
- (not (looking-at "case[ \t'/(]\\|default\\>"))
+ (not (looking-at c-switch-label-regexp))
(save-excursion
(skip-chars-forward "a-zA-Z0-9_$")
(skip-chars-forward " \t")
(t
(skip-chars-forward " \t")
(if (listp indent) (setq indent (car indent)))
- (cond ((or (looking-at "case[ \t'/(]\\|default\\>")
+ (cond ((or (looking-at c-switch-label-regexp)
(and (looking-at "[A-Za-z]")
(save-excursion
(forward-sexp 1)
(setq indent (save-excursion
(forward-char)
(backward-sexp)
+ (c-backward-to-start-of-if)
(current-indentation))))
((and (looking-at "while\\b")
(save-excursion
(looking-at "DEFUN\\b"))
c-argdecl-indent
(if (and (looking-at "\\sw\\|\\s_")
- (looking-at "[^\"\n=]*(")
+ ;; This is careful to stop at the first
+ ;; paren if we have
+ ;; int foo Proto ((int, int));
+ (looking-at "[^\"\n=(]*(")
(progn
(goto-char (1- (match-end 0)))
(setq lim (point))
;; Make sure the "function decl" we found
;; is not inside a comment.
(progn
+ ;; Move back to the `(' starting arglist
+ (goto-char lim)
(beginning-of-line)
(while (and (not comment)
(search-forward "/*" lim t))
(defun c-beginning-of-statement (count)
"Go to the beginning of the innermost C statement.
With prefix arg, go back N - 1 statements. If already at the beginning of a
-statement then go to the beginning of the preceeding one.
-If within a string or comment, move by sentences instead of statements."
+statement then go to the beginning of the preceding one.
+If within a string or comment, or next to a comment (only whitespace between),
+move by sentences instead of statements."
(interactive "p")
(let ((here (point)) state)
(save-excursion
(beginning-of-defun)
(setq state (parse-partial-sexp (point) here nil nil)))
- (if (or (nth 3 state) (nth 4 state))
+ (if (or (nth 3 state) (nth 4 state)
+ (looking-at (concat "[ \t]*" comment-start-skip))
+ (save-excursion (skip-chars-backward " \t")
+ (goto-char (- (point) 2))
+ (looking-at "\\*/")))
(forward-sentence (- count))
(while (> count 0)
(c-beginning-of-statement-1)
(interactive)
(push-mark (point))
(end-of-defun)
- (push-mark (point))
+ (push-mark (point) nil t)
(beginning-of-defun)
(backward-paragraph))
\f
+;; Idea of ENDPOS is, indent each line, stopping when
+;; ENDPOS is encountered. But it's too much of a pain to make that work.
(defun indent-c-exp (&optional endpos)
- "Indent each line of the C grouping following point.
-If optional arg ENDPOS is given, indent each line, stopping when
-ENDPOS is encountered."
+ "Indent each line of the C grouping following point."
(interactive)
(let* ((indent-stack (list nil))
(opoint (point)) ;; May be altered below.
(save-excursion (forward-char 1)
(beginning-of-defun)
(setq funbeg (point)))
+ (setq opoint funbeg)
;; Try to find containing open,
;; but don't scan past that fcn-start.
(save-restriction
(narrow-to-region funbeg (point))
(condition-case nil
(save-excursion
- (backward-up-list 1) (point))
+ (backward-up-list 1)
+ (point))
;; We gave up: must be between fcns.
;; Set opoint to beg of prev fcn
;; since otherwise calculate-c-indent
restart outer-loop-done inner-loop-done state ostate
this-indent last-sexp
at-else at-brace at-while
- last-depth
+ last-depth this-point
(next-depth 0))
;; If the braces don't match, get an error right away.
(save-excursion
(and (re-search-forward
comment-start-skip
(save-excursion (end-of-line) (point)) t)
+ ;; Make sure this isn't a comment alone on a line
+ ;; (which should be indented like code instead).
+ (save-excursion
+ (goto-char (match-beginning 0))
+ (skip-chars-backward " \t")
+ (not (bolp)))
;; Make sure the comment starter we found
;; is not actually in a string or quoted.
(let ((new-state
(if (and (car (cdr (cdr state)))
(>= (car (cdr (cdr state))) 0))
(setq last-sexp (car (cdr (cdr state)))))
- (if (or (nth 4 ostate))
+ ;; If this line started within a comment, indent it as such.
+ (if (or (nth 4 ostate) (nth 7 ostate))
(c-indent-line))
- (if (or (nth 3 state))
+ ;; If it ends outside of comments or strings, exit the inner loop.
+ ;; Otherwise move on to next line.
+ (if (or (nth 3 state) (nth 4 state) (nth 7 state))
(forward-line 1)
(setq inner-loop-done t)))
(and endpos
(point)))))
(forward-line 1)
(skip-chars-forward " \t")
- (if (eolp)
+ ;; Don't really reindent if the line is just whitespace,
+ ;; or if it is past the endpos.
+ ;; (The exit test in the outer while
+ ;; does not exit until we have passed the first line
+ ;; past the region.)
+ (if (or (eolp) (and endpos (>= (point) endpos)))
nil
(if (and (car indent-stack)
(>= (car indent-stack) 0))
;; Is it a new statement? Is it an else?
;; Find last non-comment character before this line
(save-excursion
+ (setq this-point (point))
(setq at-else (looking-at "else\\W"))
(setq at-brace (= (following-char) ?{))
(setq at-while (looking-at "while\\b"))
(current-indentation))))
((and at-while (c-backward-to-start-of-do opoint))
(setq this-indent (current-indentation)))
+ ((eq (preceding-char) ?\,)
+ (goto-char this-point)
+ (setq this-indent (calculate-c-indent)))
(t (setq this-indent (car indent-stack)))))))
;; Just started a new nesting level.
;; Compute the standard indent for this level.
(if (car indent-stack)
(- (car indent-stack))
opoint))))
+ ;; t means we are in a block comment and should
+ ;; calculate accordingly.
+ (if (eq val t)
+ (setq val (calculate-c-indent-within-comment)))
(setcar indent-stack
(setq this-indent val))))
;; Adjust line indentation according to its contents
- (if (or (looking-at "case[ \t'/(]\\|default\\>")
+ (if (or (looking-at c-switch-label-regexp)
(and (looking-at "[A-Za-z]")
(save-excursion
(forward-sexp 1)
(if (= (following-char) ?})
(setq this-indent (- this-indent c-indent-level)))
(if (= (following-char) ?{)
- (setq this-indent (+ this-indent c-brace-offset)))
+ ;; Don't move an open-brace in column 0.
+ ;; This is good when constructs such as
+ ;; `extern "C" {' surround a function definition
+ ;; that should be indented as usual.
+ ;; It is also good for nested functions.
+ ;; It is bad when an open-brace is indented at column 0
+ ;; and you want to fix that, but we can't win 'em all.
+ (if (zerop (current-column))
+ (setq this-indent 0)
+ (setq this-indent (+ this-indent c-brace-offset))))
;; Don't leave indentation in empty lines.
(if (eolp) (setq this-indent 0))
;; Put chosen indentation into effect.
(defun c-indent-region (start end)
(save-excursion
(goto-char start)
- (let ((endmark (copy-marker end)))
- (and (bolp) (not (eolp))
- (c-indent-line))
- (indent-c-exp endmark)
+ ;; Advance to first nonblank line.
+ (skip-chars-forward " \t\n")
+ (beginning-of-line)
+ (let ((endmark (copy-marker end))
+ (c-tab-always-indent t))
+ (while (and (bolp) (not (eolp)))
+ ;; Indent one line as with TAB.
+ (let ((shift-amt (c-indent-line))
+ nextline sexpbeg sexpend)
+ (save-excursion
+ ;; Find beginning of following line.
+ (save-excursion
+ (forward-line 1) (setq nextline (point)))
+ ;; Find first beginning-of-sexp for sexp extending past this line.
+ (beginning-of-line)
+ (while (< (point) nextline)
+ (condition-case nil
+ (progn
+ (forward-sexp 1)
+ (setq sexpend (point-marker)))
+ (error (setq sexpend nil)
+ (goto-char nextline)))
+ (skip-chars-forward " \t\n"))
+ (if sexpend
+ (progn
+ ;; Make sure the sexp we found really starts on the
+ ;; current line and extends past it.
+ (goto-char sexpend)
+ (backward-sexp 1)
+ (setq sexpbeg (point)))))
+ ;; If that sexp ends within the region,
+ ;; indent it all at once, fast.
+ (if (and sexpend (> sexpend nextline) (<= sexpend endmark)
+ (< sexpbeg nextline))
+ (progn
+ (indent-c-exp)
+ (goto-char sexpend)))
+ ;; Move to following line and try again.
+ (and sexpend (set-marker sexpend nil))
+ (forward-line 1)))
(set-marker endmark nil))))
\f
(defun set-c-style (style &optional global)
When going backwards, `#elif' is treated like `#else' followed by `#if'.
When going forwards, `#elif' is ignored."
(interactive "p")
- (let* ((forward (< count 0))
+ (c-forward-conditional (- count) t))
+
+(defun c-backward-conditional (count &optional up-flag)
+ "Move back across a preprocessor conditional, leaving mark behind.
+A prefix argument acts as a repeat count. With a negative argument,
+move forward across a preprocessor conditional."
+ (interactive "p")
+ (c-forward-conditional (- count) up-flag))
+
+(defun c-forward-conditional (count &optional up-flag)
+ "Move forward across a preprocessor conditional, leaving mark behind.
+A prefix argument acts as a repeat count. With a negative argument,
+move backward across a preprocessor conditional."
+ (interactive "p")
+ (let* ((forward (> count 0))
(increment (if forward -1 1))
(search-function (if forward 're-search-forward 're-search-backward))
(opoint (point))
(new))
(save-excursion
(while (/= count 0)
- (if forward (end-of-line))
- (let ((depth 0) found)
+ (let ((depth (if up-flag 0 -1)) found)
(save-excursion
;; Find the "next" significant line in the proper direction.
(while (and (not found)
;; the regexp matcher.
(funcall search-function
"#[ \t]*\\(if\\|elif\\|endif\\)"
- nil t)
- (progn
- (beginning-of-line)
- (looking-at "^[ \t]*#[ \t]*\\(if\\|elif\\|endif\\)")))
- ;; Update depth according to what we found.
+ nil t))
(beginning-of-line)
- (cond ((looking-at "[ \t]*#[ \t]*endif")
- (setq depth (+ depth increment)))
- ((looking-at "[ \t]*#[ \t]*elif")
- (if (and forward (= depth 0))
- (setq found (point))))
- (t (setq depth (- depth increment))))
- ;; If this line exits a level of conditional, exit inner loop.
- (if (< depth 0)
- (setq found (point)))
- ;; When searching forward, start from end of line
- ;; so that we don't find the same line again.
- (if forward (end-of-line))))
+ ;; Now verify it is really a preproc line.
+ (if (looking-at "^[ \t]*#[ \t]*\\(if\\|elif\\|endif\\)")
+ (let ((prev depth))
+ ;; Update depth according to what we found.
+ (beginning-of-line)
+ (cond ((looking-at "[ \t]*#[ \t]*endif")
+ (setq depth (+ depth increment)))
+ ((looking-at "[ \t]*#[ \t]*elif")
+ (if (and forward (= depth 0))
+ (setq found (point))))
+ (t (setq depth (- depth increment))))
+ ;; If we are trying to move across, and we find
+ ;; an end before we find a beginning, get an error.
+ (if (and (< prev 0) (< depth prev))
+ (error (if forward
+ "No following conditional at this level"
+ "No previous conditional at this level")))
+ ;; When searching forward, start from next line
+ ;; so that we don't find the same line again.
+ (if forward (forward-line 1))
+ ;; If this line exits a level of conditional, exit inner loop.
+ (if (< depth 0)
+ (setq found (point)))))))
(or found
(error "No containing preprocessor conditional"))
(goto-char (setq new found)))
- (setq count (- count increment))))
+ (setq count (+ count increment))))
(push-mark)
(goto-char new)))