diff --git a/semen.scm b/semen.scm
index 1afac55..4b0800e 100644
--- a/semen.scm
+++ b/semen.scm
@@ -296,8 +296,9 @@
   "The `form` must be toplevel.
 Returns #f if the form is not a function, returns the form otherwise"
   (match form
-    ((fn . _) form)
-    ((pub fn . _) form)
+    ((or ('fn . _)
+         ('pub 'fn . _)
+         ('extern 'fn . _)) form)
     (else #f)))
 
 (define (sex-fn-public? fn-form)