如何在带有 structopt crate 的子命令后使用 CLI 参数？

Question

例如，运行我的申请

./app --foo=bar get

效果很好，但是

./app get --foo=bar

产生错误：

error: Found argument '--foo' which wasn't expected, or isn't valid in this context

USAGE:
    app --foo <foo> get

代码：

use structopt::*;

#[derive(Debug, StructOpt)]
#[structopt(name = "app")]
struct CliArgs {
    #[structopt(long)]
    foo: String,
    #[structopt(subcommand)]
    cmd: Cmd,
}

#[derive(Debug, StructOpt)]
enum Cmd {
    Get,
    Set,
}

fn main() {
    let args = CliArgs::from_args();
    println!("{:?}", args);
}

依赖关系：

structopt = { version = "0.3", features = [ "paw" ] }
paw = "1.0"

Answer 1

根据issue 237，有一个global参数。没想到文档里没有提到

使用 global = true 效果很好：

use structopt::*;

#[derive(Debug, StructOpt)]
#[structopt(name = "cli")]
struct CliArgs {
    #[structopt(
        long,
        global = true,
        default_value = "")]
    foo: String,
    #[structopt(subcommand)]
    cmd: Cmd,
}

#[derive(Debug, StructOpt)]
enum Cmd {
    Get,
    Set,
}

fn main() {
    let args = CliArgs::from_args();
    println!("{:?}", args);
}

请注意，全局参数必须是可选的或具有默认值。

Answer 2

您需要为每个具有参数的命令枚举变体提供另一个结构：

use structopt::*; // 0.3.8

#[derive(Debug, StructOpt)]
struct CliArgs {
    #[structopt(subcommand)]
    cmd: Cmd,
}

#[derive(Debug, StructOpt)]
enum Cmd {
    Get(GetArgs),
    Set,
}

#[derive(Debug, StructOpt)]
struct GetArgs {
    #[structopt(long)]
    foo: String,
}

fn main() {
    let args = CliArgs::from_args();
    println!("{:?}", args);
}

./target/debug/example get --foo=1
CliArgs { cmd: Get(GetArgs { foo: "1" }) }

如何在带有 structopt crate 的子命令后使用 CLI 参数？

How to use a CLI argument after subcommand with the structopt crate?

command-line-arguments

rust

structopt