Add: Priority selector

org-agenda-ng.el

@@ -85,6 +85,7 @@ NONE-PREDS."
   (org-agenda-ng--fmap ((category #'org-agenda-ng--category-p)
                         (date #'org-agenda-ng--date-p)
                         (habit #'org-agenda-ng--habit-p)
+                        (priority #'org-agenda-ng--priority-p)
                         (todo #'org-agenda-ng--todo-p)
                         (tags #'org-agenda-ng--tags-p))
     (org-with-wide-buffer
@@ -364,5 +365,42 @@ like one returned by `date-to-day'."
            (error "Unknown date-element type: %s" (org-element-property :type date-element)))))
       (otherwise (error "COMPARATOR (%s) must be a function, and DATE (%s) must be a string" comparator target-date)))))
 
+(defmacro org-agenda-ng--priority-p (&optional comparator-or-priority priority)
+  "Return non-nil if current heading has a certain priority.
+COMPARATOR-OR-PRIORITY should be either a comparator function,
+like `<=', or a priority string, like \"A\" (in which case (\` =)
+'will be the comparator).  If COMPARATOR-OR-PRIORITY is a
+comparator, PRIORITY should be a priority string."
+  (let* (comparator)
+    (cond ((null priority)
+           ;; No comparator given: compare only given priority with =
+           (setq priority comparator-or-priority
+                 comparator '=))
+          (t
+           ;; Both comparator and priority given
+           (setq comparator comparator-or-priority)))
+    (setq comparator (cl-case comparator
+                       ;; Invert comparator because higher priority means lower number
+                       (< '>)
+                       (> '<)
+                       (<= '>=)
+                       (>= '<=)
+                       (= '=)
+                       (otherwise (user-error "Invalid comparator: %s" comparator))))
+    (setq priority (* 1000 (- org-lowest-priority (string-to-char priority))))
+    `(when-let ((item-priority (save-excursion
+                                 (save-match-data
+                                   ;; FIXME: Is the save-match-data above necessary?
+                                   (when (and (looking-at org-heading-regexp)
+                                              (save-match-data
+                                                (string-match org-priority-regexp (match-string 0))))
+                                     ;; TODO: Items with no priority
+                                     ;; should not be the same as B
+                                     ;; priority.  That's not very
+                                     ;; useful IMO.  Better to do it
+                                     ;; like in org-super-agenda.
+                                     (org-get-priority (match-string 0)))))))
+       (funcall ',comparator ,priority item-priority))))
+
 (defun org-agenda-ng--habit-p ()
   (org-is-habit-p))