Add: (blocked) predicate

README.org

@@ -254,6 +254,7 @@ Arguments are listed next to predicate names, where applicable.
 +  =tags-regexp (&rest regexps)= :: Return non-nil if current heading has tags matching one or more of ~REGEXPS~.  Tests both inherited and local tags.
      -  Aliases: ~tags*~.
 +  =todo (&optional keywords)= :: Return non-nil if current heading is a ~TODO~ item.  With ~KEYWORDS~, return non-nil if its keyword is one of ~KEYWORDS~ (a list of strings).  When called without arguments, only matches non-done tasks (i.e. does not match keywords in ~org-done-keywords~).
++  =blocked= :: Return non-nil if current heading is blocked.
 
 *** Ancestor/descendant predicates
 

org-ql.el

@@ -2377,6 +2377,11 @@ any planning prefix); it defaults to 0 (i.e. the whole regexp)."
             (from (test-timestamps (ts<= from next-ts)))
             (to (test-timestamps (ts<= next-ts to)))))))
 
+(org-ql-defpred blocked ()
+  "Return non-nil if the entry is blocked."
+  :body
+  (org-entry-blocked-p))
+
 ;; NOTE: Predicates defined: stop deferring and define normalizer and
 ;; preamble functions now.  Reversing preserves the order in which
 ;; they were defined.  Generally it shouldn't matter, but it might...