1992-05-30 21:11:25 +00:00
|
|
|
;;; reposition.el --- center a Lisp function or comment on the screen
|
|
|
|
|
1992-07-22 04:22:42 +00:00
|
|
|
;; Copyright (C) 1991 Free Software Foundation, Inc.
|
|
|
|
|
1992-07-16 21:47:34 +00:00
|
|
|
;; Author: Michael D. Ernst <mernst@theory.lcs.mit.edu>
|
|
|
|
;; Maintainer: FSF
|
1991-02-23 20:24:49 +00:00
|
|
|
|
|
|
|
;; This file is part of GNU Emacs.
|
|
|
|
|
|
|
|
;; GNU Emacs is free software; you can redistribute it and/or modify
|
|
|
|
;; it under the terms of the GNU General Public License as published by
|
1992-07-16 21:47:34 +00:00
|
|
|
;; the Free Software Foundation; either version 2, or (at your option)
|
1991-02-23 20:24:49 +00:00
|
|
|
;; any later version.
|
|
|
|
|
|
|
|
;; GNU Emacs is distributed in the hope that it will be useful,
|
|
|
|
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
|
|
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
|
|
;; GNU General Public License for more details.
|
|
|
|
|
|
|
|
;; You should have received a copy of the GNU General Public License
|
|
|
|
;; along with GNU Emacs; see the file COPYING. If not, write to
|
|
|
|
;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
|
|
|
|
|
1992-07-16 21:47:34 +00:00
|
|
|
;;; Commentary:
|
|
|
|
|
1991-02-23 20:29:31 +00:00
|
|
|
;;; Written by Michael D. Ernst, mernst@theory.lcs.mit.edu, Jan 1991.
|
1991-02-23 20:24:49 +00:00
|
|
|
|
|
|
|
;;; Reposition-window makes an entire function definition or comment visible,
|
|
|
|
;;; or, if it is already visible, places it at the top of the window;
|
|
|
|
;;; additional invocations toggle the visibility of comments preceding the
|
|
|
|
;;; code. For the gory details, see the documentation for reposition-window;
|
|
|
|
;;; rather than reading that, you may just want to play with it.
|
|
|
|
|
|
|
|
;;; This tries pretty hard to do the recentering correctly; the precise
|
|
|
|
;;; action depends on what the buffer looks like. If you find a situation
|
|
|
|
;;; where it doesn't behave well, let me know. This function is modeled
|
|
|
|
;;; after one of the same name in ZMACS, but the code is all-new and the
|
|
|
|
;;; behavior in some situations differs.
|
|
|
|
|
1992-07-16 21:47:34 +00:00
|
|
|
;;; Code:
|
|
|
|
|
1991-05-10 21:47:42 +00:00
|
|
|
;;;###autoload
|
1991-02-23 20:24:49 +00:00
|
|
|
(defun reposition-window (&optional arg)
|
|
|
|
"Make the current definition and/or comment visible.
|
|
|
|
Further invocations move it to the top of the window or toggle the
|
|
|
|
visibility of comments that precede it.
|
|
|
|
Point is left unchanged unless prefix ARG is supplied.
|
|
|
|
If the definition is fully onscreen, it is moved to the top of the
|
|
|
|
window. If it is partly offscreen, the window is scrolled to get the
|
|
|
|
definition (or as much as will fit) onscreen, unless point is in a comment
|
|
|
|
which is also partly offscreen, in which case the scrolling attempts to get
|
|
|
|
as much of the comment onscreen as possible.
|
|
|
|
Initially `reposition-window' attempts to make both the definition and
|
|
|
|
preceding comments visible. Further invocations toggle the visibility of
|
|
|
|
the comment lines.
|
|
|
|
If ARG is non-nil, point may move in order to make the whole defun
|
|
|
|
visible (if only part could otherwise be made so), to make the defun line
|
|
|
|
visible (if point is in code and it could not be made so, or if only
|
|
|
|
comments, including the first comment line, are visible), or to make the
|
|
|
|
first comment line visible (if point is in a comment)."
|
|
|
|
(interactive "P")
|
|
|
|
(let* (;; (here (save-excursion (beginning-of-line) (point)))
|
|
|
|
(here (point))
|
|
|
|
;; change this name once I've gotten rid of references to ht.
|
|
|
|
;; this is actually the number of the last screen line
|
|
|
|
(ht (- (window-height (selected-window)) 2))
|
|
|
|
(line (repos-count-screen-lines (window-start) (point)))
|
|
|
|
(comment-height
|
|
|
|
;; The call to max deals with the case of cursor between defuns.
|
|
|
|
(max 0
|
|
|
|
(repos-count-screen-lines-signed
|
|
|
|
;; the beginning of the preceding comment
|
|
|
|
(save-excursion
|
|
|
|
(forward-char 1) (end-of-defun -1)
|
|
|
|
;; Skip whitespace, newlines, and form feeds.
|
|
|
|
(re-search-forward "[^\\s \n\014]")
|
|
|
|
(backward-char 1)
|
|
|
|
(point))
|
|
|
|
here)))
|
|
|
|
(defun-height
|
|
|
|
(repos-count-screen-lines-signed
|
|
|
|
(save-excursion
|
|
|
|
(end-of-defun 1) ; so comments associate with following defuns
|
|
|
|
(beginning-of-defun 1)
|
|
|
|
(point))
|
|
|
|
here))
|
|
|
|
;; This must be positive, so don't use the signed version.
|
|
|
|
(defun-depth (repos-count-screen-lines here
|
|
|
|
(save-excursion
|
|
|
|
(end-of-defun 1)
|
|
|
|
(point))))
|
|
|
|
(defun-line-onscreen-p
|
|
|
|
(and (<= defun-height line)
|
|
|
|
(<= (- line defun-height) ht))))
|
|
|
|
(cond ((or (= comment-height line)
|
|
|
|
(and (= line ht)
|
|
|
|
(> comment-height line)
|
|
|
|
;; if defun line offscreen, we should be in case 4
|
|
|
|
defun-line-onscreen-p))
|
|
|
|
;; Either first comment line is at top of screen or (point at
|
|
|
|
;; bottom of screen, defun line onscreen, and first comment line
|
|
|
|
;; off top of screen). That is, it looks like we just did
|
|
|
|
;; recenter-definition, trying to fit as much of the comment
|
|
|
|
;; onscreen as possible. Put defun line at top of screen; that
|
|
|
|
;; is, show as much code, and as few comments, as possible.
|
|
|
|
|
|
|
|
(if (and arg (> defun-depth (1+ ht)))
|
|
|
|
;; Can't fit whole defun onscreen without moving point.
|
|
|
|
(progn (end-of-defun) (beginning-of-defun) (recenter 0))
|
|
|
|
(recenter (max defun-height 0)))
|
|
|
|
;;(repos-debug-macro "1")
|
|
|
|
)
|
|
|
|
|
|
|
|
((or (= defun-height line)
|
|
|
|
(= line 0)
|
|
|
|
(and (< line comment-height)
|
|
|
|
(< defun-height 0)))
|
|
|
|
;; Defun line or cursor at top of screen, OR cursor in comment
|
|
|
|
;; whose first line is offscreen.
|
|
|
|
;; Avoid moving definition up even if defun runs offscreen;
|
|
|
|
;; we care more about getting the comment onscreen.
|
|
|
|
|
|
|
|
(cond ((= line ht)
|
|
|
|
;; cursor on last screen line (and so in a comment)
|
|
|
|
(if arg (progn (end-of-defun) (beginning-of-defun)))
|
|
|
|
(recenter 0)
|
|
|
|
;;(repos-debug-macro "2a")
|
|
|
|
)
|
|
|
|
|
|
|
|
;; This condition, copied from case 4, may not be quite right
|
|
|
|
|
|
|
|
((and arg (< ht comment-height))
|
|
|
|
;; Can't get first comment line onscreen.
|
|
|
|
;; Go there and try again.
|
|
|
|
(forward-line (- comment-height))
|
|
|
|
(beginning-of-line)
|
|
|
|
;; was (reposition-window)
|
|
|
|
(recenter 0)
|
|
|
|
;;(repos-debug-macro "2b")
|
|
|
|
)
|
|
|
|
(t
|
|
|
|
(recenter (min ht comment-height))
|
|
|
|
;;(repos-debug-macro "2c")
|
|
|
|
))
|
|
|
|
;; (recenter (min ht comment-height))
|
|
|
|
)
|
|
|
|
|
|
|
|
((and (> (+ line defun-depth -1) ht)
|
|
|
|
defun-line-onscreen-p)
|
|
|
|
;; Defun runs off the bottom of the screen and the defun line
|
|
|
|
;; is onscreen.
|
|
|
|
;; Move the defun up.
|
|
|
|
(recenter (max 0 (1+ (- ht defun-depth)) defun-height))
|
|
|
|
;;(repos-debug-macro "3")
|
|
|
|
)
|
|
|
|
|
|
|
|
(t
|
|
|
|
;; If on the bottom line and comment start is offscreen
|
|
|
|
;; then just move all comments offscreen, or at least as
|
|
|
|
;; far as they'll go.
|
|
|
|
|
|
|
|
;; Try to get as much of the comments onscreen as possible.
|
|
|
|
(if (and arg (< ht comment-height))
|
|
|
|
;; Can't get defun line onscreen; go there and try again.
|
|
|
|
(progn (forward-line (- defun-height))
|
|
|
|
(beginning-of-line)
|
|
|
|
(reposition-window))
|
|
|
|
(recenter (min ht comment-height)))
|
|
|
|
;;(repos-debug-macro "4")
|
|
|
|
))))
|
|
|
|
|
1991-05-13 22:05:14 +00:00
|
|
|
;;;###autoload
|
1992-08-02 02:34:46 +00:00
|
|
|
(define-key esc-map "\C-l" 'reposition-window)
|
1991-05-11 18:07:11 +00:00
|
|
|
|
1991-02-23 20:24:49 +00:00
|
|
|
;;; Auxiliary functions
|
|
|
|
|
|
|
|
;; Return number of screen lines between START and END.
|
|
|
|
(defun repos-count-screen-lines (start end)
|
|
|
|
(save-excursion
|
|
|
|
(save-restriction
|
|
|
|
(narrow-to-region start end)
|
|
|
|
(goto-char (point-min))
|
|
|
|
(vertical-motion (- (point-max) (point-min))))))
|
|
|
|
|
|
|
|
;; Return number of screen lines between START and END; returns a negative
|
|
|
|
;; number if END precedes START.
|
|
|
|
(defun repos-count-screen-lines-signed (start end)
|
|
|
|
(let ((lines (repos-count-screen-lines start end)))
|
|
|
|
(if (< start end)
|
|
|
|
lines
|
|
|
|
(- lines))))
|
|
|
|
|
|
|
|
; (defmacro repos-debug-macro (case-no)
|
|
|
|
; (` (message
|
|
|
|
; (concat "Case " (, case-no) ": %s %s %s %s %s")
|
|
|
|
; ht line comment-height defun-height defun-depth)))
|
|
|
|
|
1992-05-30 21:11:25 +00:00
|
|
|
;;; reposition.el ends here
|