[O] Custom agenda: tasks scheduled today or earlier and tags

[Neilen Marais]

Hi,

I would like to make a custom agenda that 

1) filters based on tags
then
2) filters on TODO status
then
3a) shows all un-scheduled tasks
3b) shows all tasks scheduled for today or earlier

I am doing this to implement a kind of "tickler" file for GTD.  Currently I have
custom agenda that does 1) and 2):

("c" "Context Next Tasks" 
         tags-todo ("@context1|@contex2")
         ((org-agenda-skip-function '(org-agenda-skip-entry-if 
                                      'nottodo '("NEXT")))
          (org-agenda-sorting-strategy '(tag-up))
          (org-agenda-overriding-header "Context Next Tasks")
          ))

I tried defining a lambda around the org-agenda-skip-entry-if to combine logical
conditions and also tried to figure out how to find out if the schedule date is
today or earlier, but my rather weak elisp-foo let me down. Anyone done
something similar?

Thanks
Neilen