Emacs 24 OS X Fullscreen Keyboard Shortcut

Most applications on OS X Lion allow the user to toggle fullscreen mode via ⌘-ESC. While Emacs 24.3 supports native fullscreen, this keyboard shortcut is not defined by default.

To toggle fullscreen via ⌘-ESC, add the following to your .emacs or .init.el:

;; Shortcut for full screen
(defun toggle-fullscreen (&optional f)
 (interactive)
 (let ((current-value (frame-parameter nil 'fullscreen)))
 (set-frame-parameter nil 'fullscreen
 (if (equal 'fullboth current-value)
 (if (boundp 'old-fullscreen) old-fullscreen nil)
 (progn (setq old-fullscreen current-value)
 'fullboth)))))
(global-set-key [s-escape] 'toggle-fullscreen)

Original Source: Juan Céspedes