diff --git a/array_lt_op.h b/array_lt_op.h
new file mode 100644
index 0000000..3399e18
--- /dev/null
+++ b/array_lt_op.h
@@ -0,0 +1,27 @@
+
+#ifndef ARRAY_LT_OP_H
+#define ARRAY_LT_OP_H
+
+#include "core/array.h"
+#include "core/math/math_defs.h"
+#include "core/variant.h"
+
+bool operator<(const Array &p_array_a, const Array &p_array_b) {
+	int a_len = p_array_a.size();
+	int b_len = p_array_b.size();
+
+	int min_cmp = MIN(a_len, b_len);
+
+	for (int i = 0; i < min_cmp; i++) {
+		if (p_array_a.operator[](i) < p_array_b[i]) {
+			return true;
+		} else if (p_array_b[i] < p_array_a.operator[](i)) {
+			return false;
+		}
+	}
+
+	return a_len < b_len;
+}
+
+
+#endif
diff --git a/rtile_set.h b/rtile_set.h
index 689b791..6c841da 100644
--- a/rtile_set.h
+++ b/rtile_set.h
@@ -31,6 +31,7 @@
 #ifndef RTILE_SET_H
 #define RTILE_SET_H
 
+#include "array_lt_op.h"
 #include "core/resource.h"
 #include "core/object.h"
 #include "core/vector.h"