Is there a way to make changes to toggles in my .emacs file apply without re-starting Emacs?

Question

I want to be able to make the changes to my .emacs file without having to reload Emacs.

I found three questions which sort of answer what I am asking (you can find them here, here and here), but the problem is that the change I have just made is to a toggle, and as the comments to two of the answers (a1, a2) to those questions explain, the solutions given there (such as M-x reload-file or M-x eval-buffer) don't apply to toggles.

I imagine there is a way of toggling the variable again with a command, but if there is a way to reload the whole .emacs and have the all the toggles re-evaluated without having to specify them, I would prefer.

In any case, I would also appreciate if someone told me how to toggle the value of a variable so that if I just changed one toggle I can do it with a command rather than re-start Emacs just for that (I am new to Emacs). I don't know how useful this information is, but the change I applied was the following (which I got from this answer to another question):

(setq skeleton-pair t)  
(setq skeleton-pair-on-word t)  
(global-set-key (kbd "[") 'skeleton-pair-insert-maybe)  
(global-set-key (kbd "(") 'skeleton-pair-insert-maybe)  
(global-set-key (kbd "{") 'skeleton-pair-insert-maybe)   
(global-set-key (kbd "<") 'skeleton-pair-insert-maybe)  

Edit: I included the above in .emacs and reloaded Emacs, so that the changes took effect. Then I commented all of it out and tried M-x load-file. This doesn't work. The suggestion below (C-x C-e by PP works if I am using it to evaluate the toggle first time, but not when I want to undo it). I would like something that would evaluate the commenting out, if such thing exists...

Thanks :)

Answer 1

Some things you might want to try:

M-x load-file (then when prompted, type ~/.emacs enter). M-x means press the meta key (usually Esc on Linux and Windows desktops) then press the ordinary x character key.

Or, while your .emacs file is open, place your prompt just after a close bracket for the function you want to execute and type Ctrl-X, Ctrl-E. This executes that block enclosed within the nearest set of parenthesis to the left of the cursor.

This last technique I use frequently for complicated search-and-replaces. Say I'm editing an XML file and I want to move close tags onto the line before: I would type into my current XML buffer (query-replace-regexp "[ \r\n\t]*</" "</"), then place my cursor immediately after the closing parenthesis, and type Ctrl-X, Ctrl-E.

Answer 2

Not sure I actually understood your question (a bit tired), but how about marking what you have changed (C-spc) and then M-x eval-region? Unless I've done some major stuff this does what I usually need.

Answer 3

I take it that you want to experiment with turning on/off skeleton-pair?

I'd be tempted to do this by having:

(setq skeleton-pair t)    ; turns skeleton-pair on
(setq skeleton-pair nil)  ; turns skeleton-pair off

In the .emacs, and pressing C-x C-e next to the closing parenthesis for the particular version I want to try. Of course I'd have to remember to make sure that the .emacs only has the final setting that I want in it so it does the right thing next time I start up.

Answer 4

I included the above in .emacs and reloaded Emacs, so that the changes took effect. Then I commented all of it out and tried M-x load-file. This doesn't work.

It doesn't work because when you started Emacs you set a few variables and keys. Reloading .emacs with these commands commented out does not undo them. You'll have to overwrite the settings manually to undo them with

(setq variable-name nil)

and

M-x global-unset-key enter followed by the key you want to unset.

Answer 5

You can always use the *scratch* buffer to evaluate expressions.

If you'd like to set your variable:

(setq skeleton-pair t)^J

Unset:

(setq skeleton-pair nil)^J

You have to use ctrl-J to invoke the evaluation; return (or ctrl-M) won't work.

This works for all lisp expressions, BTW. If you've got a quick calculation to do:

(+ 51 33)^J 84

Or if you want to find the width of your frame: (frame-width)^J 80

It's useful if you're tinkering or have non-interactive commands or variables to evaluate.

Answer 6

Each time you evaluate elisp code, it goes to the global emacs environment of this emacs session; so if you set variable value, it is still present in the environment even if you reload your .emacs.

It would be nice if we could pre-load a .emacs (or any lisp) in a "sandbox" to test it. When I am doing heavy .emacs customization I usually open one emacs for editing the .emacs and another one to evaluate (which I can relaunch to avoid corrupting the environment).