diff --git a/stringhax.scm b/stringhax.scm
index ba4b78e..30b5d59 100644
--- a/stringhax.scm
+++ b/stringhax.scm
@@ -60,7 +60,7 @@
 		    (lp (- i 1) (- j 1))))))))
 
 (define skip-whitespace
-  (let ((non-whitespace (char-set-invert char-set:whitespace)))
+  (let ((non-whitespace (char-set-complement char-set:whitespace)))
     (lambda (s) (char-set-index s non-whitespace))))
 
 ; Why is this so complicated?