Emacs org mode: How to use "or" in org-agenda-custom-command

Question

I have tried to code my org-agenda-custom-commands to show only todo's which are either priority A or priority B. However, I am only able to do this indirectly, by filtering out todo's that are NOT priority C. Why doesn't the or-function | in my code below work the way I want? (alternative 2 and 3).

(setq org-agenda-custom-commands '(
  ("d" "Daily "(
    (tags-todo "+TODO=\"TODO\" -PRIORITY=\"C\" "  ( ; works
    (org-agenda-sorting-strategy '(priority-down))
    ))
  (tags-todo "+TODO=\"TODO\" +PRIORITY={\"B\"|\"A\"} "  ( ; works NOT
    (org-agenda-sorting-strategy '(priority-down))
    ))
  (tags-todo "+TODO=\"TODo\"  {+PRIORITY=\"B\"}|{+PRIORITY=\"A\"} "  ( ; works NOT
    (org-agenda-sorting-strategy '(priority-down))
    ))
  ))
))

Alternative 2 and 3 using the or-function | results in showing A, B and C, not only priority A and B, as was my intention.

What is wrong with my usage of the "|" function? How can I use | to show both priority A and B?

Answer 1

The contents of {} in an agenda command are regular expressions. So something like PRIORITY={\"B\"|\"A\"} will only match if PRIORITY is "A" or "B", including the quotes. You also need more escaping in you regex (\\| instead of |). A regex won't work if you don't pay the slash tax.

The correct search is +PRIORITY={A\\|B}. You can also simplify things a little by using the / syntax. Anything following a / is assumed to be a TODO keyword. So +PRIORITY={A\\|B}/TODO will find all entries with keyword TODO and priority A or B.