Problem with macro with-timer

[Andrea De Michele]

I tried to call the macro with-timer like this:

(with-timer (2) (focus-frame-by (find-frame-by-name "notification")))

But sbcl give me the following error:

The variable #:G1442 is unbound.

If I call the macro with the optional parameter id like this all works:

(with-timer (2 (gensym)) (focus-frame-by (find-frame-by-name "notification")))

I think (but I'm not sure) that the problem is that the default value
for the optional parameter id is evaluated before macroexpansion.

If I change the definition of with-timer from:

(defmacro with-timer ((delay &optional (id (gensym))) &body body)
  "Same thing as add-timer but with syntaxic sugar"
  `(add-timer ,delay
	      (lambda ()
		, at body)
	      ,id))

to:

(defmacro with-timer ((delay &optional (id '(gensym))) &body body)
  "Same thing as add-timer but with syntaxic sugar"
  `(add-timer ,delay
	      (lambda ()
		, at body)
	      ,id))

both the way to call the macro (with and without the optional id parameters) works.
-- 
Andrea De Michele