Re: unused local variables

[David Kastrup <dak@gnu.org>]

"Juanma Barranquero" <lekktu@gmail.com> writes:

> On Nov 30, 2007 10:27 AM, 山本和彦 Kazu Yamamoto <kazu@iij.ad.jp> wrote:
>
>> XEmacs warns unused local variables as if they are statically bound.
>> Also XEmacs does not warns unused local variables if they are
>> also globally defined.
>
> Are you saying that in
>
>  (defun test ()
>    (if my-dynamic-var
>        "correct"
>      "erroneous"))
>
>  (let ((my-dynamic-var t))
>    (test))
>
> you would force my-dynamic-var to be `defvar'ed to avoid a warning in
> the let?

I consider this quite reasonable.  If my-dynamic-var is used for passing
information across function boundaries, it deserves being declared in
the same scope.  There is one obvious exception:

(defun test ()
  (let ((my-variable 3))
    (funcall (lambda nil (1+ my-variable)))))

Namely, lambda functions using upvalues (well, conceptually as long as
we don't have closures).  Those are byte-compiled as well and should not
complain.

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum