diff --git a/src/fractal.cpp b/src/fractal.cpp
index 53e3b1c..830881a 100644
--- a/src/fractal.cpp
+++ b/src/fractal.cpp
@@ -81,6 +81,21 @@ branch_rule_id_t ruleset_t::add_branch_rule(token_id_t match, group_id_t group)
 	return m_branch_rules.size() - 1;
 }
 
+branch_rule_id_t ruleset_t::add_branch_rule_weighted(token_id_t match, weighted_group_id_t wgroup) {
+	if (!valid_token(match) || !valid_weighted_group(wgroup)) {
+		throw mtl::invalid_argument();
+	}
+
+	branch_rule_t rule {
+		.m_match = match,
+		.m_weighted = true,
+		.m_group = { .weighted = wgroup }
+	};
+
+	m_branch_rules.push_back(rule);
+	return m_branch_rules.size() - 1;
+}
+
 #if 0
 token_id_t generator_t::add_token(token_type_e type, mtl::fixed value) {
 	log::debug << "Adding token with type " << (int)type << endl;