feat: Leader key and General.el

users/crumb/programs/emacs/modules/syd-keybinds.el

@@ -0,0 +1,76 @@
+;;; syd-keybinds.el -*- lexical-binding: t; -*-
+;;; Universal keybindings, not /too/ tied to any particular packages.
+
+(use-package general
+  :custom (general-use-package-emit-autoloads t))
+
+(require 'general)
+
+(defvar syd-leader-key "SPC"
+  "A prefix key akin to Vim's <Leader>.")
+
+(defvar syd-localleader-key "SPC m"
+  "A prefix key akin to Vim's <LocalLeader>.")
+
+(defvar syd-alt-leader-key "M-SPC"
+  "`syd-leader', but for the states specified in `syd-alt-leader-key-states'.
+
+Often, your \"usual\" leader key will be something unavailable in the Insert
+state.  This key exists as a fallback for when you need your Leader, but must
+remain in the Insert state.  Substitute \"Insert state\" for your states of
+choice with `syd-alt-leader-key-states'.")
+
+(defvar syd-alt-localleader-key "M-SPC m"
+  "`syd-localleader', but for the states specified in `syd-alt-leader-key-states'.
+
+See `syd-alt-leader-key' for rationale.")
+
+(defvar syd-leader-key-states '(normal visual motion)
+  "States for which the Leader keys (`syd-leader-key', `syd-localleader-key')
+are active.")
+
+(defvar syd-alt-leader-key-states '(emacs insert)
+  "States for which the alternative Leader keys are active.  See
+`syd-alt-leader-key' and `syd-alt-localleader-key'.")
+
+(defvar-keymap syd-leader-map
+  :doc "Leader-prefixed commands")
+
+(defvar-keymap syd-leader-window-map
+  :doc "Window commands")
+
+(defun syd--initialise-leader ()
+  "Set up the (empty) keymap associated with `syd-leader-key',
+`syd-localleader-key', `syd-alt-leader-key', and `syd-alt-localleader-key'."
+  ;; Define `syd/leader' as a command corresponding to the prefix map
+  ;; `syd-leader-map'.
+  (define-prefix-command 'syd/leader 'syd-leader-map)
+  ;; This should help make the Leader key close to universally available.
+  ;; Ideally, *nothing* takes precedence over Leader — it's an incredibly
+  ;; important key!
+  ;; https://github.com/noctuid/evil-guide?tab=readme-ov-file#undoprevent-overridingintercept-maps
+  ;; Really, we do this because Doom does.  I'm honestly not entirely sure what
+  ;; it does.  I can't find anything useful online.
+  (define-key syd-leader-map [override-state] 'all)
+  ;; Finally, we shall bind the damned keys. }:)
+  (let ((map general-override-mode-map))
+    (require 'evil)
+    (evil-define-key* syd-leader-key-states map (kbd syd-leader-key) 'syd/leader)
+    (evil-define-key* syd-alt-leader-key-states map (kbd syd-leader-key) 'syd/leader))
+  (general-override-mode 1))
+
+(defun syd-keybinds-initialise ()
+  (syd--initialise-leader)
+  (general-define-key
+   :keymaps 'syd-leader-map
+   "." #'find-file))
+
+(syd-keybinds-initialise)
+
+;; Show possible completions for a partially-entered key sequence.
+(use-package which-key
+  :hook (on-first-input . which-key-mode)
+  :custom ((which-key-allow-evil-operators t)
+           (which-key-show-operator-state-maps t)))
+
+(provide 'syd-keybinds)