Question

例如，我试图返回当前(point)上方一行的缓冲区char位置。我的全部功能如下。

我相信(point)是字符位置，所以我想减去当前点和当前点上方位置之间的字符数。但是，这取决于当前点之上的线的长度（并不总是等于frame-char-height）。

我正在尝试模仿Eclipse注释功能，当选择某个区域时，最下面一行（带指针的行）不包含在注释区域中：

(defun comment-eclipse (&optional arg)
  (interactive)
  (let ((start (line-beginning-position))
        (end (line-end-position)))
    (when (or (not transient-mark-mode) (region-active-p))
      (setq start (save-excursion
                    (goto-char (region-beginning))
                    (beginning-of-line)
                    (point))
            end (save-excursion
                  (goto-char (region-end))
                  (end-of-line)
                  (point)))) ;; HERE: I want to return something like (- (point) (line-length))
    (comment-or-uncomment-region start end)))

对于如何实现这一目标的任何建议都将不胜感激。

更新

感谢下面的lunaryorn的回答，我改进了我的功能如下：

(defun comment-eclipse (&optional arg)
  (interactive)
  (let ((start (line-beginning-position))
        (end (line-end-position)))
    (when (or (not transient-mark-mode) (region-active-p))
      (setq start (save-excursion
                    (goto-char (region-beginning))
                    (beginning-of-line)
                    (point))
            end (save-excursion
                  (goto-char (region-end));;move point to region end
                  (end-of-line);;move point to end of line
                  (forward-line -1)
                  (end-of-line)
                  (point))))
    (comment-or-uncomment-region start end)))

Answer 1

使用current-column组合获取当前列，forward-line导航到另一行，move-to-column恢复新行上的列：

(let ((column (current-column)))
  (forward-line -1)
  (move-to-column column))

elisp：如何在当前点之上获得一点？

1 个答案: