   (concat
    (format "\\_<\\(\\(?:%s\\)?[:#]\\)"
            (regexp-opt
-            '(":" "GENERIC" "DEFER" "HOOK" "MACRO" "MATH" "POSTPONE"
-              "PRIMITIVE" "SYNTAX" "TYPED" "TYPED:")))
+            '(":" "GENERIC" "DEFER" "HOOK" "MACRO" "MATH" "MEMO" "MEMO:"
+              "POSTPONE" "PRIMITIVE" "SYNTAX" "TYPED" "TYPED:")))
    ws+ symbol))
 
 ;; [parsing-word] [vocab-word]


(defconst factor-declaration-words
  '("deprecated"
    "flushable"
    "foldable"
    "inline"

(defconst factor-symbol-definition-regex
  (syntax-and-1-symbol
   '("&" "CONSTANT" "DESTRUCTOR" "FORGET" "HELP" "LIBRARY"
     "MAIN" "MAIN-WINDOW" "STRING" "SYMBOL" "VAR")))

;; [parsing-word] [symbol-word]* ;
(defconst factor-symbols-lines-regex
