如何使用cons单元格定义并在以后删除与“`dolist`”的覆盖

Question

我正在寻找一些指导，请，以减少执行我的自定义覆盖删除功能所需的时间。导致0.1秒的延迟是因为过多的变量都有值，但是，并不是每个变量都必须使用。

我的目标是在使用第一个变量时附加一个可以设置为非nil的第二个变量，但是我不知道如何设置这个变量，以及如何将它合并到覆盖删除函数中。

也许像这样的东西是有用的：

• 如果(variable-one . t)，那么(remove-overlays (point-min) (point-max) 'display character)

在下面的示例中，每当光标访问任何字符时，M-x sub-char-mode都会在字符1、2或3上放置一个覆盖：

• 1将成为|1
• 2将成为|2
• 3将成为|3

(defvar variable-one (concat
  (propertize (char-to-string ?\u007C)
    'face 'font-lock-warning-face
    'cursor t)
  (propertize "1" 'face 'highlight 'cursor t) ))

(defvar variable-one-p (cons variable-one nil))

(defvar variable-two (concat
  (propertize (char-to-string ?\u007C)
    'face 'font-lock-warning-face
    'cursor t)
  (propertize "2" 'face 'highlight 'cursor t) ))

(defvar variable-two-p (cons variable-two nil))

(defvar variable-three (concat
  (propertize (char-to-string ?\u007C)
    'face 'font-lock-warning-face
    'cursor t)
  (propertize "3" 'face 'highlight 'cursor t) ))

(defvar variable-three-p (cons variable-three nil))

(defun substitute-character ()
  (cond
    ((eq (char-after (point)) 49)
      (setq variable-one-p (cons variable-one t))
      (overlay-put (make-overlay (point) (1+ (point))) 'display variable-one))
    ((eq (char-after (point)) 50)
      (setq variable-two-p (cons variable-two t))
      (overlay-put (make-overlay (point) (1+ (point))) 'display variable-two))
    ((eq (char-after (point)) 51)
      (setq variable-three-p (cons variable-three t))
      (overlay-put (make-overlay (point) (1+ (point))) 'display variable-three))))

(defun remove-sub-char ()
  (dolist (character `(
      ,variable-one
      ,variable-two
      ,variable-three))
    (remove-overlays (point-min) (point-max) 'display character))
 (dolist (my-variable `(
      ,variable-one-p
      ,variable-two-p
      ,variable-three-p))
    (setq my-variable nil)) )

(defun sub-char-post-command-hook ()
  (remove-sub-char)
  (substitute-character))

(define-minor-mode sub-char-mode
"A minor-mode for testing overlay-removal with cons cells."
  :init-value nil
  :lighter " OV-REMOVE"
  :keymap nil
  :global nil
  :group 'lawlist
  (cond
    (sub-char-mode
      (add-hook 'post-command-hook 'sub-char-post-command-hook nil t)
      (message "Turned ON `sub-char-mode`."))
    (t
      (remove-hook 'post-command-hook 'sub-char-post-command-hook t)
      (remove-sub-char)
      (message "Turned OFF `sub-char-mode`."))))

很抱歉在这里粘贴这个图像-请随意删除它。但是我不能把它粘贴到评论中，来回复你的评论。这是vline-style = compose和col-highlight-vline-face-flag = nil

​

​

Answer 1

第一稿(2014年8月24日)：第一稿将变量定义为cons单元-- car是预定的覆盖字符串，cdr是nil。当光标访问字符1、2或3时，将在这些字符的顶部放置一个覆盖，并使用setcdr将适用的cons单元格的cdr设置为t。覆盖删除函数包含一个变量名列表和相应的cons单元--当cons单元格的cdr为非nil(即t)时，覆盖被删除，适用的cons单元的cdr被使用setcdr设置回nil。这种设置的优点是，覆盖删除函数将快速查看并跳过cons单元cdr为nil的变量--因此在处理具有预定覆盖字符串的大量变量时节省了大量时间。

编辑(2014年8月26日)：重新编码修改代码，允许在不同缓冲区中使用相同的变量名，并设置缓冲区-本地值。相关线程是： with buffer-local variables 和 cycle and change its value。

(defvar variable-one
  (cons
    (concat
      (propertize (char-to-string ?\u007C)
        'face 'font-lock-warning-face
        'cursor t)
      (propertize "1" 'face 'highlight 'cursor t) )
    nil))

(make-variable-buffer-local 'variable-one)

(defvar variable-two
  (cons
    (concat
     (propertize (char-to-string ?\u007C)
       'face 'font-lock-warning-face
       'cursor t)
     (propertize "2" 'face 'highlight 'cursor t) )
    nil))

(make-variable-buffer-local 'variable-two)

(defvar variable-three
  (cons
    (concat
     (propertize (char-to-string ?\u007C)
       'face 'font-lock-warning-face
       'cursor t)
     (propertize "3" 'face 'highlight 'cursor t) )
  nil))

(make-variable-buffer-local 'variable-three)

(defun sub-char ()
  (cond
    ((eq (char-after (point)) 49)
      (let ((newlist (copy-list variable-one)))
        (setcdr newlist t)
        (setq-local variable-one newlist)
        (overlay-put (make-overlay (point) (1+ (point))) 'display (car variable-one))))
    ((eq (char-after (point)) 50)
      (let ((newlist (copy-list variable-two)))
        (setcdr newlist t)
        (setq-local variable-two newlist)
        (overlay-put (make-overlay (point) (1+ (point))) 'display (car variable-two))))
    ((eq (char-after (point)) 51)
      (let ((newlist (copy-list variable-three)))
        (setcdr newlist t)
        (setq-local variable-three newlist)
        (overlay-put (make-overlay (point) (1+ (point))) 'display (car variable-three))))))

(defun remove-sub-char ()
  (dolist (character `(
      (variable-one ,variable-one)
      (variable-two ,variable-two)
      (variable-three ,variable-three)))
    (when (cdr (car (cdr character)))
      (let* (
          (var (car character))
          (newlist (copy-list (car (cdr character)))) )
        (remove-overlays (point-min) (point-max) 'display (car (car (cdr character))))
        (setcdr newlist nil)
        (set (car character) newlist)
        (message "var1: %s | var2: %s | var3: %s" variable-one variable-two variable-three) ))))

(defun sub-char-post-command-hook ()
  (remove-sub-char)
  (sub-char))

(define-minor-mode sub-char-mode
"A minor-mode for testing overlay-removal with cons cells."
  :init-value nil
  :lighter " OV-REMOVE"
  :keymap nil
  :global nil
  :group 'lawlist
  (cond
    (sub-char-mode
      (add-hook 'post-command-hook 'sub-char-post-command-hook nil t)
      (message "Turned ON `sub-char-mode`."))
    (t
      (remove-hook 'post-command-hook 'sub-char-post-command-hook t)
      (remove-sub-char)
      (message "Turned OFF `sub-char-mode`."))))

Answer 2

我建议您首先摆脱您的variable-FOO-p vars:不仅它们的名称是错误的( "-p“后缀指的是谓词，这些谓词必须是函数，而不是变量)，而且它们是不必要的。与其告诉remove-overlays删除带有特定display属性的所有覆盖，不如添加自己的属性(例如，(overlay-put <youroverlay> 'vline t))，这样您就可以执行单个(remove-overlays (point-min) (point-max) 'vline t)了。当然，另一种至少也能工作的方法是保留一个单独的缓冲区局部变量(更好的是，窗口局部变量)，它包含当前放置的所有覆盖的列表。通过这种方式，您可以使用单个(mapc #'delete-overlay vline--overlays)删除这些覆盖，这样效率更高。通过移动/重用这些覆盖，而不是删除它们，然后创建新的覆盖，可以使其更加高效。