Elisp：有条件地改变键盘绑定 [英] Elisp: Conditionally change keybinding

问题描述

我正在尝试编写一个自定义选项卡完成实现，它会根据所在的位置来尝试一堆不同的完成。但是，如果没有满足完成的条件，我希望选项卡能够执行当前模式本来打算做的事情。

I'm trying to write a custom tab completion implementation which tries a bunch of different completions depending on where the point is. However, if none of the conditions for completions are met I would like tab to do what ever the current mode originally intended it to do.

这样的东西：

(defun my-custom-tab-completion ()
  (interactive)
  (cond
   (some-condition
    (do-something))
   (some-other-condition
    (do-something-else))
   (t
    (do-whatever-tab-is-supposed-to-do-in-the-current-mode))) ;; How do I do this?

目前，我正在检查具体的模式，并为该模式做正确的事情，但我真的希望一个解决方案，只是做正确的事情，而我没有明确添加一个特定模式的条件。

Currently I'm checking for specific modes and doing the right thing for that mode, but I really would like a solution that just does the right thing without me having to explicitly add a condition for that specific mode.

任何想法如何做？

谢谢！/ Erik

推荐答案

您可以使用键绑定（或其更具体的变体全局键绑定， min或模式键绑定和 local-key-binding ）来探测绑定的活动键盘图。

You could use functions such as key-binding (or its more specific variants global-key-binding, minor-mode-key-binding and local-key-binding) to probe active keymaps for bindings.

例如：

(call-interactively (key-binding (kbd "TAB")))
;; in an emacs-lisp-mode buffer:
;;    --> indent-for-tab-command
;; 
;; in a c++-mode buffer with yas/minor-mode:
;;    --> yas/expand

---

避免无限循环的一种方法您的命令必须绑定到 TAB 可以将绑定置于次模式，并在寻找 TAB 绑定时临时禁用其键盘映射：

---

One way to avoid infinite loops if your command is bound to TAB could be to put your binding in a minor mode, and temporarily disable its keymap while looking for the TAB binding:

(define-minor-mode my-complete-mode
  "Smart completion"
  :keymap (let ((map (make-sparse-keymap)))
            (define-key map (kbd "TAB") 'my-complete)
            map))

(defun my-complete ()
  (interactive)
  (message "my-complete")
  (let ((my-complete-mode nil))
    (call-interactively (key-binding (kbd "TAB")))))

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