`SELECT ... WHERE match(key, '^prefix...')`
should use index similarly to
`SELECT ... WHERE key LIKE 'prefix%'`
{
            
            Leaf,
            
            True,
            False,
            
            And,
            Or,
        };
        Type type{};
        
        const RPNElement * element = nullptr;
        
        bool negate = false;
        std::unique_ptr<Node> left = nullptr;
        std::unique_ptr<Node> right = nullptr;
    };
    
    
    
    struct Frame
    {
        std::unique_ptr<Node> can_be_true;
        std::unique_ptr<Node> can_be_false;
    };
    
    auto combine = [](std::unique_ptr<Node> left, std::unique_ptr<Node> right, Node::Type type)
    {