如何在rust中为clap结构体创建一个自定义的派生宏？

uxhixvfz  于 2022-12-26  发布在  其他
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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：

  1. #[derive(Debug, Args)]
  2. struct DeleteCommand {
  3.     /// The ID of the bill
  4.     #[clap(short, long, value_parser)]
  5.     id: Option<String>,
  6.     /// The name of the bill
  7.     #[clap(short, long, value_parser)]
  8.     name: Option<String>,
  9.     /// The value of the bill
  10.     #[clap(short, long, value_parser)]
  11.     value: Option<String>,
  12.     /// The amount of the billB
  13.     #[clap(short, long, value_parser)]
  14.     amount: Option<String>,
  15.     /// Datetime
  16.     #[clap(short, long, value_parser)]
  17.     datetime: Option<String>,
  18.     /// Currency
  19.     #[clap(short, long, value_parser)]
  20.     currency: Option<String>,
  21.     /// Recipient
  22.     #[clap(short, long, value_parser)]
  23.     recipient: Option<String>,
  24.     /// Situation
  25.     #[clap(short, long, value_parser)]
  26.     situation: Option<String>,
  27.     /// Hard
  28.     #[clap(short = 'H', long)]
  29.     hard: bool,
  30. }
  32. #[derive(Debug, Args)]
  33. struct ShowCommand {
  34.     #[clap(subcommand)]
  35.     subcommand: ShowSubcommand,
  36.     /// The ID of the bill
  37.     #[clap(short, long, value_parser)]
  38.     id: Option<String>,
  39.     /// The name of the bill
  40.     #[clap(short, long, value_parser)]
  41.     name: Option<String>,
  42.     /// The value of the bill
  43.     #[clap(short, long, value_parser)]
  44.     value: Option<String>,
  45.     /// The amount of the bill
  46.     #[clap(short, long, value_parser)]
  47.     amount: Option<String>,
  48.     /// Datetime
  49.     #[clap(short, long, value_parser)]
  50.     datetime: Option<String>,
  51.     /// Currency
  52.     #[clap(short, long, value_parser)]
  53.     currency: Option<String>,
  54.     /// Datetime
  55.     #[clap(short, long, value_parser)]
  56.     recipient: Option<String>,
  57.     /// Datetime
  58.     #[clap(short, long, value_parser)]
  59.     situation: Option<String>,
  60.     /// Head
  61.     #[clap(long, value_parser)]
  62.     head: Option<u32>,
  63.     /// Tail
  64.     #[clap(long, value_parser)]
  65.     tail: Option<u32>,
  66.     /// Order by
  67.     #[clap(short, long, value_parser)]
  68.     orderby: Option<String>,
  69. }

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：

  1. /// The ID of the bill
  2.     #[clap(short, long, value_parser)]
  3.     id: Option<String>,
  4.     /// The name of the bill
  5.     #[clap(short, long, value_parser)]
  6.     name: Option<String>,
  7.     /// The value of the bill
  8.     #[clap(short, long, value_parser)]
  9.     value: Option<String>,
  10.     /// The amount of the bill
  11.     #[clap(short, long, value_parser)]
  12.     amount: Option<String>,
  13.     /// Datetime
  14.     #[clap(short, long, value_parser)]
  15.     datetime: Option<String>,
  16.     /// Currency
  17.     #[clap(short, long, value_parser)]
  18.     currency: Option<String>,
  19.     /// Recipient
  20.     #[clap(short, long, value_parser)]
  21.     recipient: Option<String>,
  22.     /// Situation
  23.     #[clap(short, long, value_parser)]
  24.     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

  1. use clap::{Parser, Subcommand, Args};
  3. #[derive(Debug, Parser)]
  4. pub struct UserInput {
  5.     #[clap(subcommand)]
  6.     command: Command,
  7. }
  9. #[derive(Debug, Subcommand)]
  10. enum Command {
  11.     /// A command description
  12.     A(CommandA),
  13.     /// B command description
  14.     B(CommandB),
  15. }
  17. #[derive(Debug, Args)]
  18. struct CommandA {
  19.     /// The value of column x to be filtered in the database
  20.     #[clap(short, long, value_parser)]
  21.     x_value: Option<String>,
  22.     /// The value of column y to be filtered in the database
  23.     #[clap(short, long, value_parser)]
  24.     y_value: Option<String>,
  25.     /// Some particular parameter of this command
  26.     #[clap(short, long, value_parser)]
  27.     particular: Option<String>,
  28. }
  30. #[derive(Debug, Args)]
  31. struct CommandB {
  32.     /// The value of x to be filtered in the database
  33.     #[clap(short, long, value_parser)]
  34.     x_value: Option<String>,
  35.     /// The value of y to be filtered in the database
  36.     #[clap(short, long, value_parser)]
  37.     y_value: Option<String>,
  38.     /// Some particular parameter of this command
  39.     #[clap(short, long, value_parser)]
  40.     particular: Option<String>,
  41. }
  43. fn main() {
  44.     let user_input: UserInput = UserInput::parse();
  45.     print!("{:#?}", user_input)
  46. }

这就是我想要的

  1. use clap::{Parser, Subcommand, Args};
  3. #[derive(Debug, Parser)]
  4. pub struct UserInput {
  5.     #[clap(subcommand)]
  6.     command: Command,
  7. }
  9. #[derive(Debug, Subcommand)]
  10. enum Command {
  11.     /// A command description
  12.     A(CommandA),
  13.     /// B command description
  14.     B(CommandB),
  15. }
  17. #[derive(Debug, Args, Filter)]
  18. struct CommandA {
  19.     /// Some particular parameter command A
  20.     #[clap(short, long, value_parser)]
  21.     particular: Option<String>,
  22. }
  24. #[derive(Debug, Args, Filter)]
  25. struct CommandB {
  26.     /// Some particular parameter command B
  27.     #[clap(short, long, value_parser)]
  28.     particular: Option<String>,
  29. }
  31. fn main() {
  32.     let user_input: UserInput = UserInput::parse();
  33.     print!("{:#?}", user_input)
  34. }

等待行为：

  1. [user@host appname]$ appname a --help
  2. p1-a 
  3. A command description
  5. USAGE:
  6.     p1 a [OPTIONS]
  8. OPTIONS:
  9.     -x, --x-value <X_VALUE>          The value of column X to be filtered in the database
  10.     -y, --y-value <Y_VALUE>          The value of column Y to be filtered in the database
  11.     -h, --help                       Print help information
  12.     -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。

rust

1条答案

按热度按时间
mf98qq94

mf98qq941#

通过使用composition沿着#[clap(flatten)]，您几乎可以实现您想要的效果，如下所示：

  1. use clap::{Args, Parser, Subcommand};
  2. #[derive(Debug, Args)]
  3. struct CommonArgs {
  4.     /// The value of column x to be filtered in the database
  5.     #[clap(short, long, value_parser)]
  6.     x_value: Option<String>,
  7.     /// The value of column y to be filtered in the database
  8.     #[clap(short, long, value_parser)]
  9.     y_value: Option<String>,
  10. }
  12. #[derive(Debug, Args)]
  13. struct ArgsA {
  14.     #[clap(flatten)]
  15.     common_args: CommonArgs,
  16.     /// Hard
  17.     #[clap(short = 'H', long)]
  18.     particular_a: bool,
  19. }
  21. #[derive(Debug, Args)]
  22. struct ArgsB {
  23.     // #[clap(subcommand)]
  24.     // subcommand: ShowSubcommand,
  25.     #[clap(flatten)]
  26.     commmon_args: CommonArgs,
  27.     /// Head
  28.     #[clap(long)]
  29.     particular_b: Option<u32>,
  30. }
  32. #[derive(Debug, Parser)]
  33. pub struct UserInput {
  34.     #[clap(subcommand)]
  35.     command: MyCommand,
  36. }
  38. #[derive(Debug, Subcommand)]
  39. enum MyCommand {
  40.     /// A command description
  41.     A(ArgsA),
  42.     /// B command description
  43.     B(ArgsB),
  44. }
  46. fn main() {
  47.     dbg!(UserInput::parse_from("playground b --help".split(' ')));
  48. }

唯一的区别是，在访问时，您可以多输入一级间接。
这个“缺点”伴随着一个优点，那就是你可以更容易地传递部分参数，例如为ArgsA和ArgsB实现AsRef<CommonArgs>。

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