Created
May 7, 2017 20:45
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A minimalist Hydra implementation for Emacs
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| ;;; A simple/minimalist implementation of some of Hydra (github:abo-abo/hydra) functionality | |
| ;;; This code is in the public domain. | |
| (defun my-make-universal-argument-map-insinuator (keymap) | |
| (let ((name (symbol-name (cl-gensym "my-mini-hydra-universal-argument-insinuator-"))) | |
| (de-insinuator (cl-gensym))) | |
| ;; the code below relies on `lexical-binding' to capture the free variables in `lambda' | |
| (fset de-insinuator (lambda () | |
| (let* ((vec (this-command-keys-vector)) | |
| (key (if (> (length vec) 0) | |
| (vector (aref vec (1- (length vec)))) | |
| nil))) | |
| (unless (or (null key) (lookup-key keymap key)) | |
| (advice-remove 'universal-argument--mode name) | |
| (remove-hook 'post-command-hook de-insinuator))))) | |
| (lambda () | |
| (advice-add 'universal-argument--mode :after | |
| (lambda () (set-transient-map keymap)) | |
| `((name . ,name))) | |
| (add-hook 'post-command-hook de-insinuator)))) | |
| (defvar my-kill-thing-map (make-sparse-keymap) | |
| "A keymap that holds commands for killing \"things\"." | |
| (set-keymap-parent my-kill-thing-map universal-argument-map) | |
| ;;; Order-matters here: I want all the relevant keys to be bound in `my-kill-thing-map' | |
| ;;; before the fset below binds `my-kill-thing-insinuator' to a closure which captures `my-kill-thing-map' | |
| (define-key global-map [?\C-w] | |
| (lambda () | |
| (interactive) | |
| (if (use-region-p) ; this idea is from github:paldepind/composable.el | |
| (call-interactively #'kill-region) | |
| (funcall 'my-kill-thing-insinuator) | |
| (universal-argument--mode)))) | |
| (defun my-defhead (map key cmd) | |
| (define-key map key | |
| (lambda () (interactive) | |
| (call-interactively cmd) | |
| (universal-argument--mode)))) | |
| ;; now define some keys | |
| ;; a kludge to "bootstrap" the insinuator: the ?\C-w here matches the key used in in `(define-key global-map ...)' above | |
| (my-defhead my-kill-thing-map [?\C-w] #'ignore) | |
| ;; and now for some actually useful key definitions | |
| (my-defhead my-kill-thing-map [?w] #'kill-word) | |
| ;; ... | |
| ;; etc. | |
| ;; finally, pass the keymap to the insinuator | |
| (fset 'my-kill-thing-insinuator (my-make-universal-argument-map-insinuator my-kill-thing-map)) | |
| ;; that's it, folks! |
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