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Diffstat (limited to 'lisp/simple.el')
| -rw-r--r-- | lisp/simple.el | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/lisp/simple.el b/lisp/simple.el index 73138111cfe..7616d19057a 100644 --- a/lisp/simple.el +++ b/lisp/simple.el @@ -4738,6 +4738,69 @@ This also turns on `word-wrap' in the buffer." visual-line-mode turn-on-visual-line-mode :lighter " vl") +;;; Scrolling commands. + +;;; Scrolling commands which does not signal errors at top/bottom +;;; of buffer at first key-press (instead moves to top/bottom +;;; of buffer). + +(defun scroll-up-command (&optional arg) + "Scroll text of selected window upward ARG lines; or near full screen if no ARG. +If `scroll-up' cannot scroll window further, move cursor to the bottom line. +When point is already on that position, then signal an error. +A near full screen is `next-screen-context-lines' less than a full screen. +Negative ARG means scroll downward. +If ARG is the atom `-', scroll downward by nearly full screen." + (interactive "^P") + (cond + ((eq arg '-) (scroll-down-command nil)) + ((< (prefix-numeric-value arg) 0) + (scroll-down-command (- (prefix-numeric-value arg)))) + ((eobp) + (scroll-up arg)) ; signal error + (t + (condition-case nil + (scroll-up arg) + (end-of-buffer + (if arg + ;; When scrolling by ARG lines can't be done, + ;; move by ARG lines instead. + (forward-line arg) + ;; When ARG is nil for full-screen scrolling, + ;; move to the bottom of the buffer. + (goto-char (point-max)))))))) + +(put 'scroll-up-command 'isearch-scroll t) + +(defun scroll-down-command (&optional arg) + "Scroll text of selected window down ARG lines; or near full screen if no ARG. +If `scroll-down' cannot scroll window further, move cursor to the top line. +When point is already on that position, then signal an error. +A near full screen is `next-screen-context-lines' less than a full screen. +Negative ARG means scroll upward. +If ARG is the atom `-', scroll upward by nearly full screen." + (interactive "^P") + (cond + ((eq arg '-) (scroll-up-command nil)) + ((< (prefix-numeric-value arg) 0) + (scroll-up-command (- (prefix-numeric-value arg)))) + ((bobp) + (scroll-down arg)) ; signal error + (t + (condition-case nil + (scroll-down arg) + (beginning-of-buffer + (if arg + ;; When scrolling by ARG lines can't be done, + ;; move by ARG lines instead. + (forward-line (- arg)) + ;; When ARG is nil for full-screen scrolling, + ;; move to the top of the buffer. + (goto-char (point-min)))))))) + +(put 'scroll-down-command 'isearch-scroll t) + + (defun scroll-other-window-down (lines) "Scroll the \"other window\" down. For more details, see the documentation for `scroll-other-window'." |