但是abbrev里面已经用到了 last-input-event 啦， （也就是等调用到我的函数的时候就需要判断上上个按键是啥了）
(define-advice expand-abbrev (:before-while (&rest r) disable-expand-if-last-key-is-del)
(message "%s" last-input-event) ;; -> 32
last-command is a variable defined in ‘C source code’.
Its value is ‘kill-ring-save’
It is a terminal-local variable; global value is the same.
This variable may be risky if used as a file-local variable.
The last command executed.
Normally a symbol with a function definition, but can be whatever was found
in the keymap, or whatever the variable ‘this-command’ was set to by that
The value ‘mode-exit’ is special; it means that the previous command
read an event that told it to exit, and it did so and unread that event.
In other words, the present command is the event that made the previous
The value ‘kill-region’ is special; it means that the previous command
was a kill command.
‘last-command’ has a separate binding for each terminal device.
See Info node ‘(elisp)Multiple Terminals’.
只有空格才会触发 abbrev expand, 然后我的函数才会运行