 (defconst factor--regex-symbol-definition
   (factor--regex-second-word '("SYMBOL:")))
 
+(defconst factor--regex-stack-effect " ( .* )")
+
 (defconst factor--regex-using-line "^USING: +\\([^;]*\\);")
+
 (defconst factor--regex-use-line "^USE: +\\(.*\\)$")
 
 (defconst factor--font-lock-keywords
-  `(("( .* )" . 'factor-font-lock-stack-effect)
+  `((,factor--regex-stack-effect . 'factor-font-lock-stack-effect)
     ("\\(P\\|SBUF\\)\"" 1 'factor-font-lock-parsing-word)
     ,@(mapcar #'(lambda (w) (cons (concat "\\(^\\| \\)\\(" w "\\)\\($\\| \\)")
                              '(2 'factor-font-lock-parsing-word)))

  (set (make-local-variable 'indent-line-function) 'factor--indent-line)
  (setq factor-indent-width (factor--guess-indent-width))
  (setq indent-tabs-mode nil)

  (run-hooks 'factor-mode-hook))


  :type 'boolean
  :group 'factor)

(defcustom factor-help-use-minibuffer t
  "When enabled, use the minibuffer for short help messages."
  :type 'boolean
  :group 'factor)

(defcustom factor-display-compilation-output t
  "Display the REPL buffer before compiling files."
  :type 'boolean
