diff --git a/preserves.el b/preserves.el
index 772ffca..03efd42 100644
--- a/preserves.el
+++ b/preserves.el
@@ -87,6 +87,11 @@
          'font-lock-keyword-face)
    ))
 
+(defvar preserves-syntax-propertize-function
+  (syntax-propertize-rules
+   ("->" (0 "_"))
+   ("<-" (0 "_"))))
+
 (defun preserves-mode-variables ()
   (make-local-variable 'comment-use-syntax)
   (make-local-variable 'comment-start)
@@ -100,6 +105,7 @@
   (setq font-lock-defaults '(preserves-font-lock-keywords nil nil ()))
   (make-local-variable 'indent-line-function)
   (setq indent-line-function #'preserves-indent-line)
+  (setq syntax-propertize-function preserves-syntax-propertize-function)
   )
 
 (defvar preserves-indent-basic 2