changing a variable with a keystroke

[Joff <jack.joff@gmail.com>]

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Dear all,

 I'm having trouble trying to create a key combination to set a global
variable. I have tried putting the following in my .emacs file:

(global-set-key (kbd "C-l") nil)
(global-set-key (kbd "C-l C-r") '(setq dired-listing-switches "-lR")

and various permutions of the '(setq .. "-lR") part (with a single quote in
front of the -lR, without the intial single quote etc. This got me various
errors:

(global-set-key (kbd "C-l C-r") (setq dired-listing-switches -lR))   -->
Symbol's value as variable is void: -lR

(global-set-key (kbd "C-l C-r") '(setq dired-listing-switches -lR))  -->
Wrong type argument: commandp, (setq dired-listing-switches -lR) on pressing
C-l C-r

(global-set-key (kbd "C-l C-r") (setq dired-listing-switches "-lR"))  -->
Printed -lR into my buffer when I pressed C-l C-r

and so on...

so then I tried

(defun set_recursive_dired () "Set dired mode to recursive view"
  (interactive "p")
  (setq dired-listing-switches "-lR"))

(global-set-key (kbd "C-l") nil)
(global-set-key (kbd "C-l C-r") 'set_recursive_dired)
because I thought setq might not be a command (?) which got me:

call-interactively: Wrong number of arguments: (lambda nil "Set dired mode
to recursive view" (interactive "p") (setq dired-listing-switches "-lR")), 1

as you can probably tell, I'm pretty new to lisp/elisp... I have tried
'reading the error messages' and have done a lot of googling, which has got
me this far (and which suggested the above '(defun...set_recursive_dired) )

so could anyone kindly shed some light on why the above don't work, and
perhaps suggest what I should be trying? Is it a syntax thing or am I
missing the point completely?

best,
Joff

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