Re: conditional text insertion

[Deniz Dogan <deniz@dogan.se>]

On 2011-07-19 07:47, Lister Account wrote:
> I have a keybinding I just made that essentially will go to the end of a
> line, insert a semicolon, return, and auto-indent.
>
> I'd like to only add the semicolon if it doesn't already exist.
>
> In other words, go to the end of the line, if a semicolon is there,
> return.  If a semicolon is not there, add one, then return.
>
> I'm brand spanking new to emacs, and I'm sure this is a task that others
> have resolved, but I'm having trouble googling for a solution.
>
> Thanks,
> Steve

(defun hello-there ()
   (interactive)
   (move-end-of-line)
   (unless (looking-back ";")
     (insert ";"))
   (newline-and-indent))

Then you would want to bind this to only some modes, and not globally. 
E.g., this way:

(add-hook 'prog-mode-hook
           (lambda ()
             (local-set-key (kbd "C-c ;") 'hello-there)))

This binds "C-c ;" to that command.

Hope that helps,
Deniz