我试图在rust中创建一些简单的计费CLI应用程序，以供实践。它是一种数据库应用程序。我有许多操作，我需要用户能够通过列的值过滤哪些行将被操作。
下面的示例包含delete和show命令：

#[derive(Debug, Args)]
struct DeleteCommand {
    /// The ID of the bill
    #[clap(short, long, value_parser)]
    id: Option<String>,
    /// The name of the bill
    #[clap(short, long, value_parser)]
    name: Option<String>,
    /// The value of the bill
    #[clap(short, long, value_parser)]
    value: Option<String>,
    /// The amount of the billB
    #[clap(short, long, value_parser)]
    amount: Option<String>,
    /// Datetime
    #[clap(short, long, value_parser)]
    datetime: Option<String>,
    /// Currency
    #[clap(short, long, value_parser)]
    currency: Option<String>,
    /// Recipient
    #[clap(short, long, value_parser)]
    recipient: Option<String>,
    /// Situation
    #[clap(short, long, value_parser)]
    situation: Option<String>,
    /// Hard
    #[clap(short = 'H', long)]
    hard: bool,
}

#[derive(Debug, Args)]
struct ShowCommand {
    #[clap(subcommand)]
    subcommand: ShowSubcommand,
    /// The ID of the bill
    #[clap(short, long, value_parser)]
    id: Option<String>,
    /// The name of the bill
    #[clap(short, long, value_parser)]
    name: Option<String>,
    /// The value of the bill
    #[clap(short, long, value_parser)]
    value: Option<String>,
    /// The amount of the bill
    #[clap(short, long, value_parser)]
    amount: Option<String>,
    /// Datetime
    #[clap(short, long, value_parser)]
    datetime: Option<String>,
    /// Currency
    #[clap(short, long, value_parser)]
    currency: Option<String>,
    /// Datetime
    #[clap(short, long, value_parser)]
    recipient: Option<String>,
    /// Datetime
    #[clap(short, long, value_parser)]
    situation: Option<String>,
    /// Head
    #[clap(long, value_parser)]
    head: Option<u32>,
    /// Tail
    #[clap(long, value_parser)]
    tail: Option<u32>,
    /// Order by
    #[clap(short, long, value_parser)]
    orderby: Option<String>,
}

正如你所看到的，两个结构体之间有许多公共字段，因为都需要for来过滤数据库中的项。我只想创建一个派生自定义宏，它允许我在结构体中简单地重复这些行，而不需要一遍又一遍地编写它：

/// The ID of the bill
    #[clap(short, long, value_parser)]
    id: Option<String>,
    /// The name of the bill
    #[clap(short, long, value_parser)]
    name: Option<String>,
    /// The value of the bill
    #[clap(short, long, value_parser)]
    value: Option<String>,
    /// The amount of the bill
    #[clap(short, long, value_parser)]
    amount: Option<String>,
    /// Datetime
    #[clap(short, long, value_parser)]
    datetime: Option<String>,
    /// Currency
    #[clap(short, long, value_parser)]
    currency: Option<String>,
    /// Recipient
    #[clap(short, long, value_parser)]
    recipient: Option<String>,
    /// Situation
    #[clap(short, long, value_parser)]
    situation: Option<String>,

我还需要重复///行，因为它将成为CLI中每个参数的描述。

最小重现示例：

这是我的

use clap::{Parser, Subcommand, Args};

#[derive(Debug, Parser)]
pub struct UserInput {
    #[clap(subcommand)]
    command: Command,
}

#[derive(Debug, Subcommand)]
enum Command {
    /// A command description
    A(CommandA),
    /// B command description
    B(CommandB),
}

#[derive(Debug, Args)]
struct CommandA {
    /// The value of column x to be filtered in the database
    #[clap(short, long, value_parser)]
    x_value: Option<String>,
    /// The value of column y to be filtered in the database
    #[clap(short, long, value_parser)]
    y_value: Option<String>,
    /// Some particular parameter of this command
    #[clap(short, long, value_parser)]
    particular: Option<String>,
}

#[derive(Debug, Args)]
struct CommandB {
    /// The value of x to be filtered in the database
    #[clap(short, long, value_parser)]
    x_value: Option<String>,
    /// The value of y to be filtered in the database
    #[clap(short, long, value_parser)]
    y_value: Option<String>,
    /// Some particular parameter of this command
    #[clap(short, long, value_parser)]
    particular: Option<String>,
}

fn main() {
    let user_input: UserInput = UserInput::parse();
    print!("{:#?}", user_input)
}

这就是我想要的

use clap::{Parser, Subcommand, Args};

#[derive(Debug, Parser)]
pub struct UserInput {
    #[clap(subcommand)]
    command: Command,
}

#[derive(Debug, Subcommand)]
enum Command {
    /// A command description
    A(CommandA),
    /// B command description
    B(CommandB),
}

#[derive(Debug, Args, Filter)]
struct CommandA {
    /// Some particular parameter command A
    #[clap(short, long, value_parser)]
    particular: Option<String>,
}

#[derive(Debug, Args, Filter)]
struct CommandB {
    /// Some particular parameter command B
    #[clap(short, long, value_parser)]
    particular: Option<String>,
}

fn main() {
    let user_input: UserInput = UserInput::parse();
    print!("{:#?}", user_input)
}

等待行为：

[user@host appname]$ appname a --help
p1-a 
A command description

USAGE:
    p1 a [OPTIONS]

OPTIONS:
    -x, --x-value <X_VALUE>          The value of column X to be filtered in the database
    -y, --y-value <Y_VALUE>          The value of column Y to be filtered in the database
    -h, --help                       Print help information
    -p, --particular <PARTICULAR>    Some particular parameter of command A

编辑：我使用的是clap 3.2.22，但我会尽量把代码移到最新版本。