写一个VIM简化版本的Emacs的Minor-Mode
创建文件me-mode.el，放在.emacs.d里的elisp目录。
(define-minor-mode me-local-mode
"simplified vim minor mode"
:init-value nil
:global 1
:lighter " me"
:keymap me-local-mode-map)定义minor mode
(defvar me-local-mode-map
(make-keymap))定义keymap
(defun me-mode-disable ()
"Disable my evil mode on special occation"
(interactive)
(me-local-mode -1))定义disable函数
(defun me-mode-enable ()
"auto enable my evil mode when evil mode"
(interactive)
(if (and (not (bound-and-true-p me-local-mode))
(/= (point) (line-beginning-position)))
(backward-char))
(me-local-mode 1))定义enable函数，当前行不为空时，回退一个字符
(add-hook 'minibuffer-setup-hook 'me-mode-disable)
(add-hook 'minibuffer-exit-hook 'me-mode-enable)minibuffer对应处理
(provide 'me-mode)在文件最后写上provide
(require 'me-mode)
(global-set-key [escape] 'me-mode-enable)在init.el里require，并绑定ESC
(defun me-dummy-bind ()
(interactive)
(message "dummy key"))定义函数，屏蔽所有不需要的按键
(define-key me-local-mode-map (kbd "t") 'me-dummy-bind)
(define-key me-local-mode-map (kbd "T") 'me-dummy-bind)
(define-key me-local-mode-map (kbd "U") 'me-dummy-bind)
(define-key me-local-mode-map (kbd "X") 'me-dummy-bind)
(define-key me-local-mode-map (kbd "Y") 'me-dummy-bind)
(define-key me-local-mode-map (kbd "z") 'me-dummy-bind)
(define-key me-local-mode-map (kbd "Z") 'me-dummy-bind)
(define-key me-local-mode-map (kbd "DEL") 'me-dummy-bind)
(define-key me-local-mode-map (kbd "RET") 'me-dummy-bind)
(define-key me-local-mode-map (kbd "SPC") 'me-dummy-bind)所有不需要响应的按键，都屏蔽
(defun me-move-beginning ()
"move beginning and tab"
(interactive)
(move-beginning-of-line nil)
(indent-for-tab-command))(define-key me-local-mode-map (kbd "0") 'me-move-beginning)当按下0时移动到行首，并tab一下
(define-key me-local-mode-map (kbd "<") 'beginning-of-buffer)
(define-key me-local-mode-map (kbd ">") 'end-of-buffer)
(define-key me-local-mode-map (kbd "$") 'move-end-of-line)< 转到文件头 ，> 转到文件尾，$ 转到行尾
(define-key me-local-mode-map (kbd "u") 'undo)u 代替C-x u
(define-key me-local-mode-map (kbd "e") 'move-end-of-line)
(define-key me-local-mode-map (kbd "h") 'backward-char)
(define-key me-local-mode-map (kbd "i") 'me-mode-disable)
(define-key me-local-mode-map (kbd "j") 'next-line)
(define-key me-local-mode-map (kbd "k") 'previous-line)
(define-key me-local-mode-map (kbd "l") 'forward-char)e 与 $ 一样，光标移至行尾，kjhl 上下左右，i 关闭 me-mode
(defvar-local me-pre-keystrokes '()
"record pre keystrokes to perform next operation")有一些需要多个按键，比如 dw, dd, cw等等，需要把暂时用不上的放入这个list
(defvar-local me-line-selection-overlay nil
"the overlay of just line selection")使用overlay技术，主要为大V命令用的
(defvar-local me-visual-begin-pos nil
"begin pos of the visual line")配合大V命令使用，标记行选取的开始，需要计算
(defvar-local me-visual-end-pos nil
"end pos of the visual line")配合大V命令使用，标记行选取的结束，需要计算
(defun me-clear-keystrokes ()
"clear saved keystrokes"
(setq me-pre-keystrokes '()))多个按键触发了命令，需要清空保存的按键
(defun me-advice-clear-everything ()
(me-clear-keystrokes)
;;(message "clear keystrokes")
(if me-line-selection-overlay
(delete-overlay me-line-selection-overlay))
(setq me-line-selection-overlay nil)
(setq me-visual-begin-pos nil)
(setq me-visual-end-pos nil))清除所有自定义变量，保存的按键，大V用的overlay，起始结束位置
(advice-add #'keyboard-quit :before #'me-advice-clear-everything)使用advice，加入C-g的后续函数列表，保证按下C-g，不污染任何后续操作
(advice-add #'next-line :after #'me-advice-next-line)
(advice-add #'previous-line :after #'me-advice-previous-line)在大V按下的前提下，在上下行移动时，需要重新计算begin-pos和end-pos的位置
(defun me-advice-next-line (&rest r)
"move next line check visual selection"
(if me-line-selection-overlay
(progn
(me-recalc-visual-pos-next-line)
(move-overlay me-line-selection-overlay me-visual-begin-pos me-visual-end-pos)
(overlay-put me-line-selection-overlay 'face 'region))))(defun me-advice-previous-line (&rest r)
"move previous line check visual selection"
(if me-line-selection-overlay
(progn
(me-recalc-visual-pos-previous-line)
(move-overlay me-line-selection-overlay me-visual-begin-pos me-visual-end-pos)
(overlay-put me-line-selection-overlay 'face 'region))))在有大Voverlay的前提下，先计算一下位置，在重新标记overlay
(defun me-recalc-visual-pos-next-line ()
"only under visual line selection"
;;(message "%s %s %s" (line-beginning-position) me-visual-begin-pos me-visual-end-pos)
(if (and (> (line-beginning-position) me-visual-begin-pos)
(< (line-beginning-position) me-visual-end-pos))
(setq me-visual-begin-pos (line-beginning-position))
(setq me-visual-end-pos (line-end-position))))(defun me-recalc-visual-pos-previous-line ()
"only under visual line selection"
(if (and (> (line-end-position) me-visual-begin-pos)
(< (line-end-position) me-visual-end-pos))
(setq me-visual-end-pos (line-end-position))
(setq me-visual-begin-pos (line-beginning-position))))重新计算位置，分开往上和往下两个函数分开调用
(defun me-make-line-visual-selection ()
"start line visual selection"
(interactive)
(me-advice-clear-everything)
(me-refresh-visual-pos)
(if me-line-selection-overlay
(move-overlay me-line-selection-overlay me-visual-begin-pos me-visual-end-pos)
(setq me-line-selection-overlay
(make-overlay me-visual-begin-pos me-visual-end-pos)))
(overlay-put me-line-selection-overlay 'face 'region))(define-key me-local-mode-map (kbd "V") 'me-make-line-visual-selection)绑定到大V上，先清空所有自定义变量，在初始化一下起始和结束位置，之后构造overlay
(defun me-refresh-visual-pos ()
"update the var's value"
(if me-visual-begin-pos
(let ((line-begin-pos-now (line-beginning-position)))
(setq me-visual-begin-pos (if (< line-begin-pos-now me-visual-begin-pos)
line-begin-pos-now
me-visual-begin-pos)))
(setq me-visual-begin-pos (line-beginning-position)))
(if me-visual-end-pos
(let ((line-end-pos-now (line-end-position)))
(setq me-visual-end-pos (if (> line-end-pos-now me-visual-end-pos)
line-end-pos-now
me-visual-end-pos)))
(setq me-visual-end-pos (line-end-position))))计算overlay的起始和结束位置
(define-key me-local-mode-map (kbd "d") 'me-d-bind)绑定d按键
(defun me-d-bind ()
"when press d"
(interactive)
(if (null (car me-pre-keystrokes)) ;; no pre keys
(cond (mark-active ;; by set-mark-command
(kill-region (region-beginning) (region-end)))
(me-line-selection-overlay ;; by big V
(progn
(kill-region me-visual-begin-pos me-visual-end-pos)
(me-advice-clear-everything)))
(t
(push 'd me-pre-keystrokes)))
(if (eq 'd (car me-pre-keystrokes)) ;; double d
(progn
(me-trigger-dd)
(me-advice-clear-everything)))))如果没有前置按键比如dd这样的，则清除标记区域或者大V标记的overlay区域，要不然就push 到 list中，以备后续使用
如果有前置d按键，那么就触发dd，删除当前行操作，再清除所有自定义变量
(defun me-trigger-dd ()
"check if can trigger dd operation"
(let ((empty-line? (eq (line-beginning-position)
(line-end-position))))
(ignore-errors
(move-beginning-of-line nil)
(kill-line))
(if (not empty-line?)
(delete-char 1))))删除当前行，如果还剩一个字符，把那个字符也删了
(define-key me-local-mode-map (kbd "w") 'me-w-bind)绑定w按键
(defun me-w-bind ()
"when press w"
(interactive)
(cond ((null (car me-pre-keystrokes))
(forward-word))
((eq 'd (car me-pre-keystrokes))
(me-trigger-dw)
(me-advice-clear-everything))
((eq 'c (car me-pre-keystrokes))
(me-trigger-dw)
(me-advice-clear-everything)
(me-mode-disable))))如果没有前置按键，只是往前移动一个单词。
如果前置按键是d，那么触发dw，删除一个字符，并把所有变量清除
如果前置按键是c，那么触发cw，删除一个字符，清空所有两边，并disable掉me-mode
(defun me-trigger-dw ()
"kill one word"
(ignore-errors
(kill-region (point)
(progn
(forward-word)
(point)))))删除一个word，并忽略所有错误，防止影响后续函数调用
其他支持命令后续持续添加中，目前暂时够用
(define-key me-local-mode-map [escape] 'me-esc-bind)
(define-key me-local-mode-map (kbd "0") 'move-beginning-of-line)
(define-key me-local-mode-map (kbd "a") 'me-forward-char-insert)
(define-key me-local-mode-map (kbd "A") 'me-line-end-insert)
(define-key me-local-mode-map (kbd "b") 'backward-word)
(define-key me-local-mode-map (kbd "c") 'me-c-bind)
(define-key me-local-mode-map (kbd "d") 'me-d-bind)
(define-key me-local-mode-map (kbd "e") 'move-end-of-line)
(define-key me-local-mode-map (kbd "h") 'backward-char)
(define-key me-local-mode-map (kbd "i") 'me-mode-disable)
(define-key me-local-mode-map (kbd "j") 'next-line)
(define-key me-local-mode-map (kbd "k") 'previous-line)
(define-key me-local-mode-map (kbd "l") 'forward-char)
(define-key me-local-mode-map (kbd "o") 'me-next-line-insert)
(define-key me-local-mode-map (kbd "O") 'me-previous-line-insert)
(define-key me-local-mode-map (kbd "p") 'me-p-bind)
(define-key me-local-mode-map (kbd "P") 'me-upper-p-operation)
(define-key me-local-mode-map (kbd "v") 'me-v-bind)
(define-key me-local-mode-map (kbd "V") 'me-make-line-visual-selection)
(define-key me-local-mode-map (kbd "w") 'me-w-bind)
(define-key me-local-mode-map (kbd "W") 'forward-word)
(define-key me-local-mode-map (kbd "x") 'me-x-bind)
(define-key me-local-mode-map (kbd "u") 'undo)
(define-key me-local-mode-map (kbd "y") 'me-y-bind)
(define-key me-local-mode-map (kbd "<") 'beginning-of-buffer)
(define-key me-local-mode-map (kbd ">") 'end-of-buffer)
(define-key me-local-mode-map (kbd "$") 'move-end-of-line)当前支持的所有命令