virtual ValueRef evaluate(Scope& scope) const {
if(elements.size() == 0) {
return std::shared_ptr<const Tuple>(this);
}
ValueRef first = elements[0]->evaluate(scope);
return first->call(std::vector<ValueRef>(elements.begin()+1, elements.end()), scope);
}
ValueRef call(ValueRef self, std::vector<ValueRef> args) {
return self->call(self, args);
}