fix: C-i in KKP supported terminals

"C-i" and "TAB" are equivalent to Emacs. In GUI Emacs, we can bind to
[tab] instead of "TAB", permitted users to treat the two keys
differently. However, [tab] is unavailable in TTY frames, so there was
no avoiding sacrificing C-i keybinds there. With KKP support, though,
that's no longer the case.

lisp/doom-keybinds.el

@@ -50,26 +50,22 @@ and Emacs states, and for non-evil users.")
   (setq w32-lwindow-modifier 'super
         w32-rwindow-modifier 'super)))
 
-;; HACK: Emacs cannot distinguish between C-i from TAB. This is largely a
+;; HACK: Emacs can't distinguish C-i from TAB in either GUI or TTY frames.  This
-;;   byproduct of its history in the terminal, which can't distinguish them
+;;   is a byproduct of its history with the terminal, which can't distinguish
-;;   either, however, when GUIs came about Emacs created separate input events
+;;   them either, however, Emacs has separate input events for many contentious
-;;   for more contentious keys like TAB and RET. Therefore [return] != RET,
+;;   keys like TAB and RET (like [tab] and [return], aka "<tab>" and
-;;   [tab] != TAB, and [backspace] != DEL.
+;;   "<return>"), which are only triggered in GUI frames, so here, I create one
-;;
+;;   for C-i. Won't work in TTY frames, though. Doom's :os tty module has a
-;;   In the same vein, this keybind adds a [C-i] event, so users can bind to it
+;;   workaround for that though.
-;;   independently of TAB. Otherwise, it falls back to keys bound to C-i.
+(define-key input-decode-map
-(define-key key-translation-map [?\C-i]
+  [?\C-i] (cmd! (if (when-let ((keys (this-single-command-raw-keys)))
-  (cmd! (if (let ((keys (this-single-command-raw-keys)))
+                      (and (display-graphic-p)
-              (and keys
                            (not (cl-position 'tab    keys))
                            (not (cl-position 'kp-tab keys))
-                   (display-graphic-p)
+                           ;; Fall back if no <C-i> keybind can be found,
-                   ;; Fall back if no <C-i> keybind can be found, otherwise
+                           ;; otherwise we've broken all pre-existing C-i
-                   ;; we've broken all pre-existing C-i keybinds.
+                           ;; keybinds.
-                   (let ((key
+                           (key-binding (vconcat (cl-subseq keys 0 -1) [C-i]) nil t)))
-                          (doom-lookup-key
-                           (vconcat (cl-subseq keys 0 -1) [C-i]))))
-                     (not (or (numberp key) (null key))))))
                     [C-i] [?\C-i])))
 
 

modules/os/tty/config.el

@@ -57,4 +57,14 @@
     [M-return] (kbd "M-RET")
     [M-tab] (kbd "M-TAB")
     [M-backspace] (kbd "M-DEL")
-    [M-delete] (kbd "M-DEL")))
+    [M-delete] (kbd "M-DEL"))
+
+  ;; HACK: Allow C-i to function independently of TAB in KKP-supported
+  ;;   terminals. Requires the `input-decode-map' entry in
+  ;;   lisp/doom-keybinds.el.
+  (define-key! key-translation-map
+    [?\C-i] (cmd! (if-let (((kkp--terminal-has-active-kkp-p))
+                           (keys (this-single-command-raw-keys))
+                           ((> (length keys) 2))
+                           ((equal (cl-subseq keys -3) [27 91 49])))
+                      [C-i] [?\C-i]))))