1 files changed, 1 insertions, 0 deletions
diff --git a/filter.h b/filter.h
index 136bb67b..4eb317d1 100644
--- a/filter.h
+++ b/filter.h
@@ -26,6 +26,7 @@
 
 extern val filters;
 extern val filter_k, lfilt_k, rfilt_k, to_html_k, from_html_k;
+extern val upcase_k, downcase_k, fun_k;
 
 val trie_lookup_begin(val trie);
 val trie_value_at(val node);