Very short key bindings for emacs commands [duplicate]

Question

There are some text actions that I use so often in emacs that the user-made commands I currently use, invoked with the standard M-x ... RET procedure do not satisfy me. I would like to replace their key bindings with shorter ones, with as few keystrokes as possible (ideally two, as it is in elaborate IDEs). It seems I cannot use keyboard macros here because according to the manual, Keyboard macros are not "powerful enough" to achieve what ordinary Emacs commands do (according to https://www.gnu.org/software/emacs/manual/html_node/emacs/Keyboard-Macros.html).

Perhaps I can override some builtin C- or M- commands ? There are several that I will probably never need anyway. Is there a safe, recommended way to do this ?

An example : wrap the currently selected text into phpbb italics tags. All the solutions I could find, here or there, use M-x. I tried to make a non-interactive version as follows :

(defun wrap-with-italics-phpbb-tag (start end)
  "Wraps the selected text or the point with a tag"
  (let (string)
    (if mark-active 
        (list (setq string (buffer-substring start end))
          (delete-region start end)))
    (yas/expand-snippet (point)
                        (point)
                        (concat "[i]" string "[/i]"))))

(global-set-key (kbd "C-i") 'wrap-with-italics-phpbb-tag)

This does not work because global-set-keys expects an interactive command.

Answer 1

The interactive declaration at the beginning of a function distinguishes an ordinary function, to be used only programmatically, from a "command", to be used (in addition or solely) by the user. A command bound to a key is thus nothing more than an interactive function bound to a key.

All functions bound to keys are also available via M-x*: You can actually do M-x forward-char.

So, it's really that simple. If you want to bind a function to a key, declare it to be interactive by adding an interactive spec. Think of it as a type declaration and of binding a non-interactive function to a key as the semantic equivalent of a type error.

In other words: all you have to do in order to get a key binding from the (already interactive) functions you were linking to is to add your global-set-key. That's it.

Footnote:

[*] Striktly speaking, you can have anonymous interactive functions, e.g.

(define-key global-map (kbd "C-c c")
  (lambda () (interactive) (message "Help! I'm crazy")))

Whether that is a good idea is another matter.

Answer 2

You seem to be confused by (interactive).

Anything that you call by yourself using M-x or using a keyboard sequence has to be marked interactive. Add that and your example above works. You are supposed to do that.

Also, the very idea of emacs is that commands are defined by names and they tend to be long to be descriptive. You are supposed to come up with your own keybindings (i.e. your "short names"). However, it is highly recommended to follow conventions.

I highly recommend you start using hydras to define groups of key binding.