使用 Rust 的 CLAP Parser 特性获取命令行参数列表

Question

我正在尝试使用一个 CLI 工具根据一些指定的正则表达式编辑文件。

调试中，举个例子：

cargo run -- folder ./tests/test_files -t emails ip

或者在生产中，例如：

raf folder ./tests/test_files -t emails ip

folder

是一个子命令，第一个参数是

folder

的路径，

-t

或

--types

参数应该有一个正则表达式类型的列表（例如，对应于电子邮件的正则表达式，对应于 ip 的正则表达式地址等）。

以下是试图实现这一目标的结构列表：

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

#[derive(Debug, Parser)]
#[clap(author, version, about, name = "raf")]
pub struct Opts {
    #[clap(subcommand)]
    pub cmd: FileOrFolder,
}

#[derive(Debug, Subcommand)]
pub enum FileOrFolder {
    #[clap(name = "folder")]
    Folder(FolderOpts),
    #[clap(name = "file")]
    File(FileOpts),
}

#[derive(Args, Debug)]
pub struct FolderOpts {
    /// `path` of the directory in which all files should be redacted, e.g. ./tests/test_files
    #[clap(parse(from_os_str))]
    pub path: std::path::PathBuf,

    /// The type of redaction to be applied to the files, e.g. -t sgNRIC emails
    #[clap(short, long)]
    pub types: Vec<String>,
}

#[derive(Args, Debug)]
pub struct FileOpts {
    #[clap(parse(from_os_str))]
    pub path: std::path::PathBuf,
    #[clap(short, long)]
    pub types: Vec<String>,
}

基本上，结构

types

和

FolderOpts

的字段

FileOpts

是有问题的。

运行时错误是：

... raf> cargo run -- folder ./tests/test_files -t emails ip
    Finished dev [unoptimized + debuginfo] target(s) in 0.26s
     Running `target\debug\raf.exe folder ./tests/test_files -t emails ip`
error: Found argument 'ip' which wasn't expected, or isn't valid in this context

USAGE:
    raf.exe folder [OPTIONS] <PATH>

For more information try --help
error: process didn't exit successfully: `target\debug\raf.exe folder ./tests/test_files -t emails ip` (exit code: 2)

如何让

-t emails, ip

翻译成

FolderOpts.types

=

vec!["emails", "ip"]

？

Answer 1

对于同一选项的多个参数，您可以使用

num_args

：

use clap::Parser;
#[derive(Debug, Parser)]
struct Opts {
    #[arg(short, long, num_args = 1..)]
    types: Vec<String>,
}

fn main() {
    let o = Opts::parse_from(["program_name", "-t", "first", "second"]);
    dbg!(o);
}

输出：

[src/main.rs:10] o = Opts {
    types: [
        "first",
        "second",
    ],
}

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