如何取消日历中的一个日期--删除重叠

Question

错误消息：let: Wrong type argument: overlayp, (#<overlay from 478 to 480 in *Calendar*>)

mouse-1成功地标记日历中的日期。内置函数只提供删除所有的覆盖，而不只是一个特定的日期。谁能帮我删除一个标记日期的覆盖--我在想这可能是mouse-2或U。我想使用跳过语法-向前/向后，因为有些日期只有一位数字，有些有两位数字--光标可能在两位数字之间，或者在日期的两边。我想我们需要一个起点和终点。

(define-key calendar-mode-map [mouse-1] (lambda () (interactive)
  (calendar-mark-visible-date (calendar-cursor-to-date t))))

(define-key calendar-mode-map "U" (lambda () (interactive)
  (cond
    ((save-excursion (> 0 (skip-syntax-backward "w")))
      (skip-syntax-backward "w")
      (let ((beg (point)))
        (skip-syntax-forward "w")
          (let ((end (point)))
            (delete-overlay (overlays-in beg end)))))
    ((save-excursion (< 0 (skip-syntax-forward "w")))
      (skip-syntax-forward "w")
      (let ((end (point)))
        (skip-syntax-backward "w")
          (let ((beg (point)))
            (delete-overlay (overlays-in beg end))))))))

编辑(2013年12月12日)：基于@Drew的有用答案的第一份工作草案。添加了mouse-set-point和交互式代码来支持上述功能。统一的键盘快捷键使mouse-1激活/禁用点处的覆盖--现在使用overlays-at。

编辑(2014年1月1日)：若要区分点处的一个或多个覆盖，请参见以下线程：How to distinguish between different overlays at point与该线程中的示例不同，取决于点上是否存在特定覆盖，可以执行不同的操作。

(defvar lawlist-calendar-face (make-face 'lawlist-calendar-face))
(set-face-attribute 'lawlist-calendar-face nil
  :background "LightCoral" :foreground "black")

(define-key calendar-mode-map [mouse-1] (lambda (event) (interactive "e")
  (mouse-set-point event)
  (if (not (overlays-at (point)))
    (calendar-mark-visible-date (calendar-cursor-to-date t) lawlist-calendar-face)
  (cond
    ;; cursor is one whitespace to the left of 1 to 9
    ((and
        (save-excursion (< 0 (skip-chars-forward " \t")))
        (not (save-excursion (< 0 (skip-syntax-forward "w")))))
      (save-excursion
        (let ((beg (point)))
          (skip-chars-forward " \t")
          (skip-syntax-forward "w")
            (let ((end (point)))
              (mapc 'delete-overlay (overlays-in beg end))))))
    ;; cursor is sandwiched between a digit on each side.
    ((and
        (save-excursion (> 0 (skip-syntax-backward "w")))
        (save-excursion (< 0 (skip-syntax-forward "w"))))
      (save-excursion
        (skip-syntax-backward "w")
        (let ((beg (point)))
          (skip-syntax-forward "w")
            (let ((end (point)))
              (mapc 'delete-overlay (overlays-in beg end))))))
    ;; cursor is to the far right of one or two digit dates
    ((and
        (save-excursion (> 0 (skip-syntax-backward "w")))
        (not (save-excursion (< 0 (skip-syntax-forward "w")))))
      (save-excursion
        (skip-syntax-backward "w")
        (let ((beg (point)))
          (skip-syntax-forward "w")
            (let ((end (point)))
              (mapc 'delete-overlay (overlays-in beg end))))))
    ;; cursor to the far left of one or two digits dates
    ((and
        (save-excursion (< 0 (skip-syntax-forward "w")))
        (not (save-excursion (> 0 (skip-syntax-backward "w")))))
      (save-excursion
        (skip-syntax-forward "w")
        (let ((end (point)))
          (skip-syntax-backward "w")
            (let ((beg (point)))
              (mapc 'delete-overlay (overlays-in beg end))))))))))

Answer 1

Wrt错误：

delete-overlay期望有一个覆盖作为它的参数。您正在向它传递一个覆盖列表(空的或非空的)。您应该遍历列表，例如，使用while、dolist或mapc。