diff --git a/libwccl/parser/grammar.g b/libwccl/parser/grammar.g
index a81a3163af677ff584e570f90b010444d3f7f91f..d0969330dcbd9616d80f1d52afed89500710608d 100644
--- a/libwccl/parser/grammar.g
+++ b/libwccl/parser/grammar.g
@@ -46,7 +46,7 @@ header {
 	#include <libwccl/ops/functions/strset/getlemmas.h>
 	
 	#include <libwccl/ops/functions/tset/agrfilter.h>
-  #include <libwccl/ops/functions/tset/catfilter.h>
+	#include <libwccl/ops/functions/tset/catfilter.h>
 	#include <libwccl/ops/functions/tset/getsymbols.h>
 	#include <libwccl/ops/functions/tset/getwordclass.h>
 	#include <libwccl/ops/functions/tset/getsymbolsinrange.h>