Tab-bar related finishing touches.

* lisp/tab-bar.el (tab-bar-tab-name-ellipsis): Use shorter name
instead of tab-bar-tab-name-truncated-ellipsis.
(tab-bar-new-tab-to) <defcustom>: Add 'function' option.
(tab-bar-new-tab-to) <function>: Use it.

* lisp/tab-line.el (tab-line-close-tab): Add missing arg 'tab' to
tab-line-close-tab-function funcall.

Author: link0ff

lisp/tab-bar.el

@@ -360,19 +360,19 @@ to `tab-bar-tab-name-truncated'."
   :group 'tab-bar
   :version "27.1")
 
-(defvar tab-bar-tab-name-truncated-ellipsis
+(defvar tab-bar-tab-name-ellipsis
   (if (char-displayable-p ?…) "…" "..."))
 
 (defun tab-bar-tab-name-truncated ()
   "Generate tab name from the buffer of the selected window.
 Truncate it to the length specified by `tab-bar-tab-name-truncated-max'.
-Append ellipsis `tab-bar-tab-name-truncated-ellipsis' in this case."
+Append ellipsis `tab-bar-tab-name-ellipsis' in this case."
   (let ((tab-name (buffer-name (window-buffer (minibuffer-selected-window)))))
     (if (< (length tab-name) tab-bar-tab-name-truncated-max)
         tab-name
       (propertize (truncate-string-to-width
                    tab-name tab-bar-tab-name-truncated-max nil nil
-                   tab-bar-tab-name-truncated-ellipsis)
+                   tab-bar-tab-name-ellipsis)
                   'help-echo tab-name))))
 
 
@@ -722,11 +722,14 @@ Interactively, ARG selects the ARGth different frame to move to."
 If `leftmost', create as the first tab.
 If `left', create to the left from the current tab.
 If `right', create to the right from the current tab.
-If `rightmost', create as the last tab."
+If `rightmost', create as the last tab.
+If the value is a function, it should return a number as a position
+on the tab bar specifying where to insert a new tab."
   :type '(choice (const :tag "First tab" leftmost)
                  (const :tag "To the left" left)
                  (const :tag "To the right" right)
-                 (const :tag "Last tab" rightmost))
+                 (const :tag "Last tab" rightmost)
+                 (function :tag "Function"))
   :group 'tab-bar
   :version "27.1")
 
@@ -773,7 +776,9 @@ After the tab is created, the hooks in
                           ('leftmost 0)
                           ('rightmost (length tabs))
                           ('left (1- (or from-index 1)))
-                          ('right (1+ (or from-index 0)))))))
+                          ('right (1+ (or from-index 0)))
+                          ((pred functionp)
+                           (funcall tab-bar-new-tab-to))))))
       (setq to-index (max 0 (min (or to-index 0) (length tabs))))
       (cl-pushnew to-tab (nthcdr to-index tabs))
 

lisp/tab-line.el

@@ -709,7 +709,7 @@ from the tab line."
           (set-window-prev-buffers nil (assq-delete-all buffer (window-prev-buffers)))
           (set-window-next-buffers nil (delq buffer (window-next-buffers)))))
        ((functionp tab-line-close-tab-function)
-        (funcall tab-line-close-tab-function)))
+        (funcall tab-line-close-tab-function tab)))
       (force-mode-line-update))))