diff --git a/hydra.el b/hydra.el
index 3b73f44..df764cc 100644
--- a/hydra.el
+++ b/hydra.el
@@ -447,7 +447,7 @@ The expressions can be auto-expanded according to NAME."
         offset)
     (while (setq start
                  (string-match
-                  "\\(?:%\\( ?-?[0-9]*\\)\\(`[a-z-A-Z/0-9]+\\|(\\)\\)\\|\\(?:_\\( ?-?[0-9]*\\)\\([a-z-~A-Z0-9/<>]+\\)_\\)"
+                  "\\(?:%\\( ?-?[0-9]*\\)\\(`[a-z-A-Z/0-9]+\\|(\\)\\)\\|\\(?:_\\( ?-?[0-9]*\\)\\([a-z-~A-Z0-9/|?<>]+\\)_\\)"
                   docstring start))
       (cond ((eq ?_ (aref (match-string 0 docstring) 0))
              (let* ((key (match-string 4 docstring))