Programmers typing on the UK Mac keyboard have a problem with # # is commonly used in programming languages and the Mac UK layout puts # on ⌥ 3 (Alt-3), as opposed to Shift-3 on the US layout or Windows UK layout. This is a particular problem in Emacs, which interprets the ⌥ (Alt) key press as the Meta key and so Emacs receives M-3 instead of #. My first approach was just to make M-3 insert #: (define-key brf-mode-map "\M-3" (lambda () (interactive) (insert ?#))) This hoses bookmark 3 in brf-mode , but losing one bookmark seemed like a compromise I could live with. However it turns out this was a pretty dumb idea (😖), as it stops all the uses of # other than inserting, for example searching for # ! It also stops me typing the command for server-edit ( C-x # ) , which is a very common usage for me. Looking around the web, people had some "creative solutions" for this problem: Inserting # handling into all the various keymaps This seems to be the m...