feat(emacs): Tab control

- Removes default "implicit naming" behaviour.
- Adds keybinds.

users/crumb/programs/emacs/init.el

@@ -61,6 +61,7 @@
 (require 'syd-projects)
 (require 'syd-scratch)
 (require 'syd-smartparens)
+(require 'syd-tabs)
 (require 'syd-tooling)
 (require 'syd-tramp)
 (require 'syd-ui)

users/crumb/programs/emacs/lib/syd-prelude.el

@@ -87,6 +87,7 @@ KEYS is an alist of the parsed keywords."
   nil)
 
 (defmacro with-transient-after (hook-or-function &rest forms)
+  (declare (indent defun))
   (let ((hook-name (gensym "transient-hook"))
         (hook-or-function* (gensym "hook-or-function")))
     `(let* ((,hook-or-function* ,hook-or-function))

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

@@ -0,0 +1,66 @@
+;;; syd-tabs.el -*- lexical-binding: t; -*-
+
+;; Many themes neglect tab-bar customisation, leaving it completely unstyled.
+;; `vim-tab-bar' will style it to look like Vim's tab-bar, but more importantly,
+;; it will colour it to match the current theme.
+(use-package vim-tab-bar
+  :commands vim-tab-bar-mode)
+
+(with-eval-after-load 'tab-bar
+  (setq tab-bar-new-tab-to 'rightmost)
+
+  (defun syd-tab-bar-make-free-name ()
+    (cl-loop for i from 1
+             with candidate = nil
+             do (setq candidate (format "#%d" i))
+             while (tab-bar--tab-index-by-name candidate)
+             finally return candidate))
+
+  (defun syd-tab-bar-rename-tab (tab new-name)
+    ;; HACK: Using `tab-bar-rename-tab' doesn't work, for some reason.  This
+    ;; relies on the internal representation of tabs.
+    (setf (alist-get 'name tab) new-name
+          (alist-get 'explicit-name tab) t))
+
+  (defvar syd-tab-bar-name-function #'syd-tab-bar-make-free-name
+    "Nullary function expected to return the name for a new tab.")
+
+  (syd-add-hook 'tab-bar-tab-post-open-functions
+    (defun syd-tab-bar--name-new-tab-h (tab)
+      "Hooks to `tab-bar-tab-post-open-functions' such that new tabs will be
+given \"explicit names\" that are static."
+      (syd-tab-bar-rename-tab tab (funcall syd-tab-bar-name-function)))
+    (defun syd-tab-bar--show-tab-bar-h (_tab)
+      "Show the tab-bar if it is not already visible.  See
+`syd-tab-bar-hide-tab-bar-h'."
+      (unless vim-tab-bar-mode
+        (vim-tab-bar-mode 1))))
+
+  (syd-add-hook 'tab-bar-tab-pre-close-functions
+    (defun syd-tab-bar-hide-tab-bar-h (_tab _final-tab-p)
+      "Hide the tab-bar when there is only a single tab to show.  See
+`syd-tab-bar--show-tab-bar-h'."
+      (when (<= (length (tab-bar-tabs)) 2) ; The tab hasn't yet been removed.
+        (tab-bar-mode -1))))
+
+  (defun syd-tab-bar-new-named-tab (name)
+    (interactive (list (read-string "Tab name: ")))
+    ;; Relies on `syd-tab-bar--name-new-tab-h'.
+    (let ((syd-tab-bar-name-function (lambda () name)))
+      (tab-bar-new-tab)))
+
+  (general-def
+    :prefix-map 'syd-leader-tab-map
+    "[" #'tab-previous
+    "]" #'tab-next
+    "r" #'tab-rename
+    "R" #'tab-rename
+    "n" #'tab-new
+    "N" #'syd-tab-bar-new-named-tab
+    "d" #'tab-close)
+  (general-def
+    :keymaps 'syd-leader-map
+    "TAB" `("Tabs" . ,syd-leader-tab-map)
+    "<tab>" `("Tabs" . ,syd-leader-tab-map)))
+
+(provide 'syd-tabs)