Setting a parametric org-agenda-skip-function?

[Alan Schmitt <alan.schmitt@polytechnique.org>]

Hello,

I'm trying to have a custom agenda where I say I want to skip some
tags. I wrote a function that does what I want (it takes two arguments:
the list of tags to keep, and a boolean that says whether entries with
no tags should be kept). The function works well, but for some reason it
is not called. Here is how I try to call it:

 ("w" "Work Agenda"
  ((agenda ""
           ((org-agenda-skip-function 
             '(org-agenda-skip-entry-unless-tags 
               my-work-tags
               t))))

I make org-agenda-skip-entry-unless-tags as debugged, and when I call
this agenda view, I don't go in the debugger, so I guess it is not
called.

I tried adding a "lambda ()" at the beginning, or getting rid of the
quote, but it does not work.

Any suggestion as to what I'm doing wrong?

Thanks,

Alan

PS: here are the functions this depends on

(defun as/has-tag (tags-to-test taglist &optional trueifempty)
  "return true if a tag in TAGS-TO-TEST is in TAGLIST. If
  TRUEIFEMPTY is non-nil, then returns true if TAGS-TO-TEST is
  empty."
  (or
   (and trueifempty (not tags-to-test))
   (catch 'match
     (mapc (lambda (tag)
             (when (member tag taglist)
               (throw 'match t)))
           tags-to-test)
     nil))
  )

(defun org-agenda-skip-entry-unless-tags (tags &optional keepempty)
  "Skip entries that do not contain specified tags.
TAGS is a list specifying which tags should be displayed.
Inherited tags will be considered. If keepempty is non-nil,
entries with no tags will be kept."
  (let ((next-headline (save-excursion (or (outline-next-heading) (point-max))))
        (current-headline (or (and (org-at-heading-p)
                                   (point))
                              (save-excursion (org-back-to-heading)))))
    (let ((atags (org-get-tags-at current-headline)))
      (if (as/has-tag atags tags keepempty)
          nil
        next-headline))))