Window numbers for Emacs !

• Introduction
• Changelog
  • Jan. 26 2026
  • Aug. 26 2024
  • Sep. 11 2019
  • Nov. 15 2018
  • Initial release: what's changed since window-numbering
• Installation
  • Using Melpa
  • Manual installation
• How to use
• Configuration
  • Keybindings
  • Customize options
  • Configuration file example
• Future developments

Introduction

This package is a fork of the winum package, which is itself a fork of the window-numbering package.

Compared to winum, this fork adds support for windows having arbitrary Lisp values as identifiers, as opposed to strictly increasing numbers. The public API is largely the same, however, and simple numbers are still the default.

Changelog

Jan. 26 2026

• Added support for changing how Lisp indices are displayed via winum-display-function.
• Removed winum-mode-line-p predicate.

Aug. 26 2024

• Added support for arbitrary Lisp objects (non-nil, compared with equal) as indices.
• Added customize variable winum-auto-assign-function to control auto-assigning behavior.

Sep. 11 2019

• Added customize variable winum-ignored-buffers-regexp to ignored buffers based on regexps.

Nov. 15 2018

• Added customize variable winum-format, a format string to configure how the window number appears in the mode-line

Initial release: what's changed since window-numbering

This package brings a lot of additions to the old window-numbering:

• Number sets across multiple frames, giving a smoother experience of multi-screen Emacs
• 3 possible scopes: frame-local, visible frames or all frames
• get-window-by-number public function, needed in Spacemacs and for future developments.
• Unlimited window numbers
• select-window-by-number can now be used interactively to select a window using prefix arg or read-from-minibuffer, allowing the selection of an unlimited number.
• Ignore buffers by name
• ;;;###autoload all functions that should have public visibility
• Improved customize integration
• Removed window-numbering-before-assign-hook, which just duplicated window-numbering-assign-func in a more complicated fashion
• New default key bindings under the C-x w prefix, to be compliant with Emacs key bindings conventions and native Emacs key bindings
• winum-set-keymap-prefix helper function to change the prefix more easily
• More detailed README.org
• Improved docstrings
• Simplified implementation for better readability

Installation

Using Melpa

The recommended way of installing winum is from the Melpa package repository:

M-x package-install RET winum RET

You will find instructions to setup Melpa here if you don't have it setup yet.

Once the package is installed, you need to load and activate winum-mode in your Emacs configuration:

  (require 'winum)

  (winum-mode)

Manual installation

• Clone the repo:

  cd /path/to/install/folder
  git clone https://github.com/deb0ch/emacs-winum

• Add the following to your Emacs configuration:

  (add-to-list 'load-path "/path/to/install/folder/emacs-winum/")

  (require 'winum)

  (winum-mode)

How to use

Key binding	Description
C-x w <n>	select window <n>, where <n> ranges from 0 to 9. A negative argument deletes the window.
C-x w `	select window by index. Integer indices can be given as prefix arg, or the index will be read from minibuffer.

• select-window-0-or-10 By default, C-x w 0 is bound to select-window-0-or-10. If window 0 is not assigned, it will act on the window 10 instead. You can rebind this to the more straightforward select-window-0 if you prefer.

• select-window-by-index

  If you happen to have more than 10 windows, or if you want to select a window that doesn't have an integer index, you can use the select-window-by-index function, bound by default to C-x w `.

  This function allows several ways to input the window number:

  • Use a numbered prefix argument.
    Ex: C-1 C-2 C-x w ` to select window 12.
  • Use the default prefix argument to delete current window.
    Ex: C-u C-x w ` to delete current window.
  • If no prefix argument is given, an un-evaluated Lisp value is read from minibuffer.

Configuration

Keybindings

The default prefix for key bindings is C-x w for compatibility with native Emacs bindings.

If you don't like C-x w, you can set a prefix of your choosing using the function winum-set-keymap-prefix:

  (winum-set-keymap-prefix (kbd "C-c"))

This function overrides the value of winum-keymap, so you should call it before customization of winum-keymap and/or after customization of winum-base-map. Its argument must be a key sequence, like the ones returned by kbd.

If you prefer no to use a prefix and have even shorter bindings, you can also override winum-keymap in the minor mode bindings table:

  (setq winum-keymap
      (let ((map (make-sparse-keymap)))
        (define-key map (kbd "C-`") 'winum-select-window-by-index)
        (define-key map (kbd "C-²") 'winum-select-window-by-index)
        (define-key map (kbd "M-0") 'winum-select-window-0-or-10)
        (define-key map (kbd "M-1") 'winum-select-window-1)
        (define-key map (kbd "M-2") 'winum-select-window-2)
        (define-key map (kbd "M-3") 'winum-select-window-3)
        (define-key map (kbd "M-4") 'winum-select-window-4)
        (define-key map (kbd "M-5") 'winum-select-window-5)
        (define-key map (kbd "M-6") 'winum-select-window-6)
        (define-key map (kbd "M-7") 'winum-select-window-7)
        (define-key map (kbd "M-8") 'winum-select-window-8)
        map))

  (require 'winum)

  (winum-mode)

Note that it is important to set winum-keymap before the require.

You can also use the more conventional define-key on winum-keymap:

  (define-key winum-keymap (kbd "C-x y o l o") 'winum-select-window-by-index)

NB: Both ` and ² are mapped to winum-select-window-by-number by default to handle both qwerty and azerty keyboard layouts. If you are using a different kind of layout, the recommended place to map it is the key beside 1.

Customize options

Several options are available through Emacs' Customize interface under convenience > winum:

• winum-scope Frames affected by a number set. Choices are 'frame-local 'visible or 'global. Default: 'global
• winum-reverse-frame-list If t, order frames by reverse order of creation. Has effect only when winum-scope is not 'frame-local. Default: nil
• winum-minibuffer-auto-assign If non-nil, winum-mode automatically assigns this index to the minibuffer. Default: 0

• winum-assign-functions

  List of functions called for each window by `winum-mode'.

  These functions allow for deterministic assignment of numbers to windows. Each function is called for every window. A function should return the number to be assigned to a window or nil. The first function to output a number for a given window will determine this window's number (if more than 1 function assigns a number a warning will be logged in the messages buffer).

  If the list is empty or if every function returns nil for a given window winum will proceed to automatic number assignment.

  Since this list is meant to allow custom window assignment for mutiple packages at once it should never be directly set, only added to and removed from.

  These functions, along with winum-auto-assign-0-to-minibuffer, are the only way to have 0 assigned to a window.

  Example: always assign Calculator the number 9 and NeoTree the number 0:

    (defun winum-assign-9-to-calculator-8-to-flycheck-errors ()
      (cond
       ((equal (buffer-name) "*Calculator*") 9)
       ((equal (buffer-name) "*Flycheck errors*") 8)))
  
    (defun winum-assign-0-to-neotree ()
      (when (string-match-p (buffer-name) ".*\\*NeoTree\\*.*") 10))
  
    (add-to-list 'winum-assign-functions #'winum-assign-9-to-calculator-8-to-flycheck-errors)
    (add-to-list 'winum-assign-functions #'winum-assign-0-to-neotree)

  Default: nil

• winum-auto-assign-function The function called to auto-assign indices to windows. This function is called after winum-assign-functions to automatically assign indices to the remaining windows. It must take in a list of windows and call the function winum--assign to assign an index to each, while avoiding assigning any indices already taken (stored in winum--assigned-indices). Members of this list should be tested for using `equal'. Default: #'winum--auto-assign
• winum-auto-setup-mode-line When nil, winum-mode will not display window numbers in the mode-line. You might want this to be nil if you use a package that already manages window numbers in the mode-line. Default: t
• winum-format Format string defining how the window number looks like in the mode-line. This string is passed to the format function along with the result of winum-get-number-string. Default: " %s "
• winum-mode-line-position The position in the mode-line winum-mode displays the number. Default: 1
• winum-ignored-buffers List of buffers to ignore when assigning numbers. Default: '(" which-key")
• winum-ignored-buffers-regexp List of regexps for buffer names. Matching buffers will be ignored when assigning numbers. See Emacs' documentation on regexps for syntax. Default: '()
• face: winum-face Face used for the number in the mode-line.

Configuration file example

Here is an example that you could put in your .emacs, which includes all available winum options.

  (setq winum-keymap
      (let ((map (make-sparse-keymap)))
        (define-key map (kbd "C-`") 'winum-select-window-by-index)
        (define-key map (kbd "C-²") 'winum-select-window-by-index)
        (define-key map (kbd "M-0") 'winum-select-window-0-or-10)
        (define-key map (kbd "M-1") 'winum-select-window-1)
        (define-key map (kbd "M-2") 'winum-select-window-2)
        (define-key map (kbd "M-3") 'winum-select-window-3)
        (define-key map (kbd "M-4") 'winum-select-window-4)
        (define-key map (kbd "M-5") 'winum-select-window-5)
        (define-key map (kbd "M-6") 'winum-select-window-6)
        (define-key map (kbd "M-7") 'winum-select-window-7)
        (define-key map (kbd "M-8") 'winum-select-window-8)
        map))

  (require 'winum)

  (defun winum-assign-9-to-calculator-8-to-flycheck-errors ()
    (cond
     ((equal (buffer-name) "*Calculator*") 9)
     ((equal (buffer-name) "*Flycheck errors*") 8)))

  (defun winum-assign-0-to-neotree ()
    (when (string-match-p (buffer-name) ".*\\*NeoTree\\*.*") 10))

  (add-to-list 'winum-assign-functions #'winum-assign-9-to-calculator-8-to-flycheck-errors)
  (add-to-list 'winum-assign-functions #'winum-assign-0-to-neotree)

  (set-face-attribute 'winum-face nil :weight 'bold)

  (setq window-numbering-scope            'global
        winum-reverse-frame-list          nil
        winum-minibuffer-auto-assign      0
        winum-assign-func                 'my-winum-assign-func
        winum-auto-setup-mode-line        t
        winum-format                      " %s "
        winum-mode-line-position          1
        winum-ignored-buffers             '(" *which-key*")
        winum-ignored-buffers-regexp      '(" \\*Treemacs-.*"))

  (winum-mode)

Future developments

• send buffer to numbered window Send current window's buffer to window N. With prefix argument focus will follow.
• swap buffer with numbered window Same as previous, but will swap buffers instead of just sending them.
• Evilify Adapt the package to the famous `evil-mode` and use a leader key.
• Override native other-window (C-x o) to use window numbers
• Autocomplete read-from-minibuffer
• Things that you have thought of and I haven't 😸