我正在寻求一些帮助来修改fill-column-indicator.el由 Alp Aker 设计，以便垂直线在空白处可见（无论空白模式是否处于活动状态）。
以下是该库的 Github 存储库的链接：
https://github.com/alpaker/Fill-Column-Indicator/blob/master/fill-column-indicator.el https://github.com/alpaker/Fill-Column-Indicator/blob/master/fill-column-indicator.el
目前，垂直线在空白处不可见。
下面的代码，当与fill-column-indicator.el，创建一条跟踪当前光标列位置的垂直线。我已经检查过的代码fill-column-indicator.el但是，我无法找到在存在空格时阻止出现垂直线的代码部分。
(defun fci-mode-current-column ()
(setq fill-column (current-column))
(setq cursor-type '(hbar . 2))
(fci-mode t))
(add-hook 'post-command-hook 'fci-mode-current-column)
(source: lawlist.com http://www.lawlist.com/images/fill_column_indicator.png)
2014 年 5 月 1 日：创建了第一份工作草案。
2014 年 5 月 2 日：修改了多个 fci 模式功能，并包含了先前草案的部分内容。
2014 年 5 月 3 日：修复了选项卡右侧列的突出显示问题。合并了准后命令挂钩，以精确控制何时使用垂直标尺重绘缓冲区，并删除了以前由 fci 模式使用的挂钩。
2014 年 5 月 4 日：添加了部分兼容性whitespace-mode使用设置(setq whitespace-style '(face space-mark tab-mark newline-mark) ). The 前景 for tab-mark and newline-mark被突出显示。但是，那背景未突出显示，因为每个标记跨越多于一列（但宽度point只等于一）。
;;;;;;;;;;;;;;;;;;;;;;;;; LAWLIST MODIFICATIONS ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; http://stackoverflow.com/a/23418459/2112489
;;
;; In order to use these modifications to enable vertical highlighting of the
;; current column, the library `fill-column-indicator.el` by Alp Aker is needed.
;; https://github.com/alpaker/Fill-Column-Indicator
;; The code set forth hereinbelow is intended to replace functions or variables
;; within the aforementioned library that contain the same names. There are
;; also a few new functions and variables below.
(define-minor-mode fci-mode
:group 'fci-mode
:lighter " fci"
:global nil
:init-value nil
(if fci-mode
;; Enabling.
(condition-case error
(progn
(fci-check-user-options)
(fci-process-display-table)
(fci-set-local-vars)
(fci-get-frame-dimens)
;; (dolist (hook fci-hook-assignments)
;; (add-hook (car hook) (nth 1 hook) nil (nth 2 hook)))
(setq fci-column (current-column))
(setq fci-tab-width tab-width)
(setq fci-limit
(if fci-newline
(1+ (- fci-column (length fci-saved-eol)))
fci-column))
(fci-make-overlay-strings)
(fci-update-all-windows t)
(if linum-mode
(linum-update-current)))
(error
(fci-mode 0)
(signal (car error) (cdr error))))
;; Disabling.
(fci-restore-display-table)
(fci-restore-local-vars)
(dolist (hook fci-hook-assignments)
(remove-hook (car hook) (nth 1 hook) (nth 2 hook)))
(fci-delete-overlays-buffer)
(dolist (var fci-internal-vars)
(set var nil))))
(defvar my-column-overlay nil
"The overlays used in this buffer.")
(make-variable-buffer-local 'my-column-overlay)
(defvar my-cursor-point nil
"Point used to prevent the formation of a cursor overlay.
It must be set within the function `fci-redraw-region`.")
(make-variable-buffer-local 'my-cursor-point)
(defun fci-put-overlays-region (start end)
"Place overlays displaying the fill-column rule between START and END."
(let* (my-last-column fci-overlay my-overlay-beg my-overlay-end)
(setq cursor-type 'hollow)
(goto-char end)
(while (re-search-backward "\n" start t)
(setq my-last-column (current-column))
(setq fci-overlay (make-overlay (match-beginning 0) (match-beginning 0)))
(overlay-put fci-overlay 'fci t)
(cond
((< my-last-column fci-limit)
(overlay-put fci-overlay 'after-string fci-pre-limit-string))
((> my-last-column fci-limit)
(overlay-put fci-overlay 'after-string fci-post-limit-string))
(t
(overlay-put fci-overlay 'after-string fci-at-limit-string)))
(setq my-overlay-beg (progn (move-to-column fci-column) (point)))
(setq my-overlay-end (+ 1 my-overlay-beg))
(setq my-column-overlay (make-overlay my-overlay-beg my-overlay-end ))
(cond
;; text, excluding tabs
((and
(not (save-excursion (move-to-column (+ 1 fci-column))
(eq (preceding-char) 9)))
(not (eq my-cursor-point my-overlay-beg))
(< fci-column my-last-column))
(overlay-put my-column-overlay 'face
'(:background "DarkRed") ) )
;; tab with text to the right
((and
(not (bobp)) ;; do NOT try to go beyond the beginning of the buffer
(not (not (save-excursion (move-to-column fci-column)
(backward-char 1) (eq (char-after (point)) 9))))
(not (save-excursion (move-to-column (+ 1 fci-column))
(eq (char-after (point)) 9)))
(save-excursion (move-to-column fci-column)
(eq (char-after (point)) 9))
(not (eq my-cursor-point my-overlay-beg))
(< fci-column my-last-column))
(overlay-put my-column-overlay 'face
'(:foreground "Red" :weight bold) ) )
;; tab with text to the left
((and
(not (bobp)) ;; do NOT try to go beyond the beginning of the buffer
(not (save-excursion (move-to-column fci-column)
(backward-char 1) (eq (char-after (point)) 9)))
(save-excursion (move-to-column fci-column)
(eq (char-after (point)) 9))
(not (eq my-cursor-point my-overlay-beg))
(< fci-column my-last-column))
(overlay-put my-column-overlay 'face
'(:foreground "Red" :weight bold) ) )
;; tab sandwiched between a tab on each side
((and
(not (bobp)) ;; do NOT try to go beyond the beginning of the buffer
(save-excursion (move-to-column fci-column)
(eq (char-after (point)) 9))
(not (eq
(save-excursion (move-to-column fci-column)
(re-search-backward "\t" (point-at-bol) t) (point))
(save-excursion (move-to-column (+ fci-column 1))
(re-search-backward "\t" (point-at-bol) t) (point))))
(not (eq my-cursor-point my-overlay-beg))
(< fci-column my-last-column))
(overlay-put my-column-overlay 'face
'(:foreground "Red" :weight bold) ) )
;; end of line
((= fci-column my-last-column)
(overlay-put my-column-overlay 'face
'(:foreground "Red" :weight bold) ) )
;; cursor
((and
(eq my-cursor-point my-overlay-beg)
(not (eq (preceding-char) 9))
(< fci-column my-last-column))
(overlay-put my-column-overlay 'face
'(:weight bold) ) )) )))
(defun fci-delete-overlays-region (start end)
"Delete overlays displaying the fill-column rule between START and END."
(mapc #'(lambda (o) (if (overlay-get o 'fci) (delete-overlay o)))
(overlays-in start end))
(let ((ovs (overlays-in start end)))
(dolist (ov ovs)
(unless (member ov (list hl-line-overlay))
(delete-overlay ov)))) )
(defun fci-redraw-region (start end _ignored)
"Erase and redraw the fill-column rule between START and END."
;; Needed to prevent and then ultimately create a cursor overlay.
(setq my-cursor-point (point))
(save-match-data
(save-excursion
(let ((inhibit-point-motion-hooks t))
(goto-char end)
(setq end (line-beginning-position 2))
(fci-delete-overlays-region start end)
(fci-put-overlays-region start end)))))
(defvar quasi-this-command-functions '(next-line previous-line left-char right-char
self-insert-command newline delete-backward-char delete-forward-char
indent-for-tab-command mwheel-scroll lawlist-mwheel-scroll end-of-visual-line
beginning-of-visual-line end-of-buffer beginning-of-buffer lawlist-forward-entity
lawlist-backward-entity left-word right-word forward-word backward-word
lawlist-forward-element lawlist-backward-element)
"Variable list of functions that trigger the `fci-quasi-post-command-hook`.")
(defvar fci-quasi-major-mode-inclusions '(text-mode emacs-lisp-mode perl-mode
js-mode css-mode dired-mode lawlist-tex-mode c-mode html-mode snippet-mode)
"Variable list of major modes where the `fci-quasi-post-command-hook` operates.")
(defun fci-quasi-post-command-hook ()
(unless (minibufferp)
(when
(and
(memq major-mode fci-quasi-major-mode-inclusions)
(memq this-command quasi-this-command-functions))
(fci-mode 1))))
(add-hook 'post-command-hook 'fci-quasi-post-command-hook)
(add-hook 'change-major-mode-hook 'fci-quasi-post-command-hook)
(add-hook 'window-configuration-change-hook 'fci-quasi-post-command-hook)
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(source: lawlist.com http://www.lawlist.com/images/fill_column_indicator_b.png)