SGI Freeware 1999 August/SGI Freeware 1999 August.iso/dist/fw_xemacs.idb/usr/freeware/lib/xemacs-20.4/lisp/modes/c-fill.el.z/c-fill.el

Text File | 1998-05-21 | 8.7 KB | 273 lines

;;; C comment mode - An auto-filled comment mode for gnu c-mode.
;;;
;;; Author:      Robert Mecklenburg
;;;        Computer Science Dept.
;;;              University of Utah
;;; From: [e-mail] (Robert Mecklenburg)
;;;   Also [e-mail]
;;; (c) 1986, University of Utah
;;;
;;; Everyone is granted permission to copy, modify and redistribute
;;; this file, provided the people they give it to can.

;;; Synched up with: Not in FSF.

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;
;;; I have written a "global comment" minor-mode which performs auto-fill,
;;; fill-paragraph, and auto-indentation functions.  This function only
;;; works for comments which occupy an entire line (not comments to the
;;; right of code).  The mode has several options set through variables.
;;; If the variable c-comment-starting-blank is non-nil multi-line
;;; comments come out like this:
;;;
;;;     /*
;;;      * Your favorite
;;;      * multi-line comment.
;;;      */
;;;
;;; otherwise they look like this:
;;;
;;;     /* Your Favorite
;;;      * multi-line comment.
;;;      */
;;;
;;; If the variable c-comment-hanging-indent is non-nil K&R style comments
;;; are indented automatically like this:
;;;
;;;     /* my_func - For multi-line comments with hanging indent
;;;      *         the text is lined up after the dash.
;;;      */
;;;
;;; otherwise the text "the text" (!) is lined up under my_func.  If a
;;; comment fits (as typed) on a single line it remains a single line
;;; comment even if c-comment-starting-blank is set.  If
;;; c-comment-indenting is non-nil hitting carriage return resets the
;;; indentation for the next line to the current line's indentation
;;; (within the comment) like this:
;;;
;;;     /* Typing along merrily....
;;;      *     Now I indent with spaces, when I hit return
;;;      *     the indentation is automatically set to
;;;      *     ^ here.
;;;      */
;;;
;;; Due to my lack of understanding of keymaps this permanently resets M-q
;;; to my own fill function.  I would like to have the comment mode
;;; bindings only in comment mode but I can't seem to get that to work.
;;; If some gnu guru can clue me in, I'd appreciate it.
;;;
(defvar c-comment-starting-blank t
  "*Controls whether global comments have an initial blank line.")
(defvar c-comment-indenting t
  "*If set global comments are indented to the level of the previous line.")
(defvar c-comment-hanging-indent t
  "*If true, comments will be automatically indented to the dash.")
(defvar c-hang-already-done t
  "If true we have performed the haning indent already for this comment.")


;;;
;;; c-comment-map - This is a sparse keymap for comment mode which
;;;             gets inserted when c-comment is called.
;;;
(defvar c-comment-mode-map ()
  "Keymap used in C comment mode.")
(if c-comment-mode-map
    ()
  (setq c-comment-mode-map (copy-keymap c-mode-map))
  (define-key c-comment-mode-map "\e\r" 'newline)
  (define-key c-comment-mode-map "\eq" 'set-fill-and-fill)
  (define-key c-comment-mode-map "\r" 'set-fill-and-return))

;;;
;;; c-comment - This is a filled comment mode which can format
;;;         indented text, do hanging indents, and symetric
;;;         placement of comment delimiters.
;;;
(defun c-comment ()
  "Edit a C comment with filling and indentation.
This performs hanging indentation, symmetric placement of delimiters,
 and Indented-Text mode style indentation.  Type 'M-x apropos
c-comment' for information on options."
  (interactive)
  (let
      ;; Save old state.
      ((auto-fill-function (if c-comment-indenting
                   'do-indented-auto-fill 'do-auto-fill))
;       (comment-start nil)
       (comment-multi-line t)
       (comment-start-skip "/*\\*+[     ]*")
       (paragraph-start-ref paragraph-start)
       fill-prefix paragraph-start paragraph-separate opoint)

    ;; Determine if we are inside a comment.
    (setq in-comment
      (save-excursion
        (and (re-search-backward "/\\*\\|\\*/" 0 t)
         (string= "/*" (buffer-substring (point) (+ (point) 2))))))

    ;; Indent the comment and set the fill prefix to comment continuation
    ;; string.  If we are already in a comment get the indentation on
    ;; the current line.
    (setq c-hang-already-done nil)

    ;; Set the beginning of the comment and insert the blank line if needed.
    (use-local-map c-comment-mode-map)
    (if (not in-comment)
    (progn (c-indent-line)
           (insert "/* ")
           (setq fill-prefix (get-current-fill (point)))
           (recursive-edit)

           ;; If the comment fits on one line, place the close
           ;; comment at the end of the line.  Otherwise, newline.
           (setq opoint (point))
           (if (and (save-excursion (beginning-of-line)
                    (search-forward "/*" opoint t))
            (<= (+ (current-column) 3) 79))
           (insert " */")
         (insert "\n*/"))

           (c-indent-line))
      (progn (setq fill-prefix (get-current-fill (point)))
         (recursive-edit)
         (search-forward "*/" (buffer-size) t)
         (forward-line 1)))

    ;; If starting blank enabled, insert a newline, etc., but only if
    ;; this comment requires multiple lines.
    (if c-comment-starting-blank
    (save-excursion
      (setq opoint (point))
      (forward-line -1)
      (if (or (null (search-forward "/*" opoint t))
          (null (search-forward "*/" opoint t)))
          (progn
        (search-backward "/*")
        (re-search-forward comment-start-skip opoint t)
        (setq fill-prefix (get-current-fill (point)))
        (if (not (looking-at "\n"))
            (insert ?\n fill-prefix))))))
;            (indent-new-comment-line))))))

    ;; Move cursor to indentation.
    (c-indent-line)
    (use-local-map c-mode-map)
    )
  )


;;;
;;; set-fill-and-fill - Get the current fill for this line and fill
;;;             the paragraph.
;;;
(defun set-fill-and-fill (arg)
  "Get the fill-prefix and fill the current paragraph."

  (interactive "P")
  (setq fill-prefix (get-current-fill (point)))
  (fill-paragraph arg))

;;;
;;; set-fill-and-return - Set the current fill prefix and
;;;               indent-new-comment-line.
;;;
(defun set-fill-and-return ()
  "Set the current fill prefix and move to the next line."

  (interactive)
  (if c-comment-indenting
      (setq fill-prefix (get-current-fill (point))))
  (insert ?\n fill-prefix))

;;;
;;; do-indented-auto-fill - Perform the auto-fill function, but get
;;;                 the fill-prefix first.
;;;
(defun do-indented-auto-fill ()
  "Perform auto-fill, but get fill-prefix first."

  (let ((opoint (point)))
    (save-excursion
      (move-to-column (1+ fill-column))
      (skip-chars-backward "^ \t\n")
      (if (bolp)
      (re-search-forward "[ \t]" opoint t))
      ;; If there is a space on the line before fill-point,
      ;; and nonspaces precede it, break the line there.
      (if (save-excursion
        (skip-chars-backward " \t")
        (not (bolp)))

      ;; If we are wrapping to a new line, figure out the indentation on
      ;; the current line first.
      (progn
        (setq fill-prefix (get-current-fill opoint))
        (insert ?\n fill-prefix)))))
;        (indent-new-comment-line)))))
  )


;;;
;;; get-current-fill - Get the fill-prefix for the current line.  This
;;;                assumes that the valid fill prefix is between
;;;                (beginning-of-line) and (point).
;;;
(defun get-current-fill (pnt)
  "Get the current fill prefix.
A valid fill prefix must be between the beginning of the line and point."

  (let ((opoint pnt) fill last-char)
    (save-excursion
      (beginning-of-line)
      (setq fill
        (buffer-substring (point)
                  (progn
                (re-search-forward comment-start-skip opoint t)
                (point))))

      ;; Be sure there is trailing white space.
      (setq last-char (substring fill (1- (length fill)) (length fill)))
      (if (and (not (string= " " last-char))
           (not (string= "    " last-char)))
      (setq fill (concat fill " ")))

      (setq fill (replace-letter fill "/" " "))

      ;; Get the hanging indentation if we haven't already.
      (if (and c-comment-hanging-indent (not c-hang-already-done))
      (let ((curr (point))
        (opnt (progn (end-of-line) (point))))
        (beginning-of-line)
        (if (search-forward " - " opnt t)
        (progn
          (setq fill (concat fill (make-string (- (point) curr) 32)))
          (setq c-hang-already-done t)))))

      ;; Set the paragraph delimiters.
      (setq paragraph-start (concat paragraph-start-ref
                    "\\|^"
                    (regexp-quote
                     (substring fill
                        0 (1- (length fill))))
                    "$"))
      (setq paragraph-separate paragraph-start))
    fill)
  )


;;;
;;; replace-letter - Given a string, an old letter and a new letter,
;;;              perform the substitution.
;;;
(defun replace-letter (str old-letter new-letter)
  (let (new-str c
    (sp 0)
    (size (length str)))
    (while (< sp size)
      (setq c (substring str sp (1+ sp)))
      (setq new-str (concat new-str (if (string= c old-letter) new-letter c)))
      (setq sp (1+ sp)))
    new-str))