我正在尝试制作一个带有自定义棋盘尺寸的井字游戏。我希望这很难被破解，所以如果输入无效或出现错误，我使用递归来获取棋盘测量值。然而，这对我来说似乎不是很干净，我想知道是否有更好/更生疏的方法来实现同样的事情。

main函数中的代码

let board_size_str = get_board_size_string();
let (x_pos, width, height) = get_board_measurement(&board_size_str);

函数

fn get_board_size_string() -> String {
    println!("Select the size of the board in the following format: 5x5 or 7x7");
    println!("The size can be from 3x3 to 30x30");
    print!("Size: ");
    std::io::stdout().flush().expect("Failed to flush stdout!");
    let mut board_size_str = String::new();
    std::io::stdin().read_line(&mut board_size_str).expect("Failed to read board size!");
    println!();

    board_size_str
}

fn get_board_measurement(board_size_str: &str) -> (usize, i64, i64) {
    let x_pos = get_x_pos(board_size_str);
    let width = get_board_width(board_size_str, x_pos);
    let height = get_board_height(board_size_str, x_pos);

    (x_pos, width, height)
}

fn get_x_pos(board_size_str: &str) -> usize {
    let x_pos_option = board_size_str.chars().position(|c| c == 'x');

    match x_pos_option {
        Some(x_pos) => x_pos,
        None => {
            println!("Board size must contain an x!");
            let board_size_str = get_board_size_string();
            get_x_pos(&board_size_str)
        }
    }
}

fn get_board_width(board_size_str: &str, x_pos: usize) -> i64 {
    let width_result = board_size_str[..x_pos].parse::<i64>();
    
    match width_result {
        Ok(width) => width,
        Err(_) => {
            println!("Invalid board width!");
            let board_size_str = get_board_size_string();
            get_board_width(&board_size_str, get_x_pos(&board_size_str))
        }
    }
}

fn get_board_height(board_size_str: &str, x_pos: usize) -> i64 {
    let height_result = board_size_str[x_pos + 1..].trim().parse::<i64>();

    match height_result {
        Ok(height) => height,
        Err(_) => {
            println!("Invalid board height!");
            let board_size_str = get_board_size_string();
            get_board_height(&board_size_str, get_x_pos(&board_size_str))
        }
    }
}