static void get_states(StateMachinePtr sm, NodePtr root, StateSet& states) {
assert(root->get_op() == Op::sm_state_condition);
if (root->size() == 2) {
get_states(sm, root->get_operand(0), states);
root = root->get_operand(1);
} else {
root = root->get_operand(0);
}
std::string statename = root->get_token().get_text();
int index = sm->get_state_by_name(statename);
if (index < 0) {
throw Exception(root->get_location(),
"unknown state: " + statename);
}
states.set(index);
}
