use clap::Parser;
use clap_adapters::prelude::*;

#[derive(Debug, Parser)]
struct Cli {
    /// Path to a config file of arbitrary Json
    #[clap(long)]
    config: PathTo<JsonOf<serde_json::Value>>,
}

fn main() {
    // Create a config file in a temporary directory
    let config_dir = tempfile::tempdir()?;
    let config_path = config_dir.path().join("config.json");
    let config_path_string = config_path.display().to_string();

    // Write a test config of {"hello":"world"} to the config file
    let config = serde_json::json!({"hello": "world"});
    let config_string = serde_json::to_string(&config)?;
    std::fs::write(&config_path, &config_string)?;

    // Parse our CLI, passing our config file path to --config
    let cli = Cli::parse_from(["app", "--config", &config_path_string]);
    let data = cli.config.data();

    // We should expect the value we get to match what we wrote to the config
    assert_eq!(data, &serde_json::json!({"hello":"world"}));
}

扩展clap-adapters

你可以通过定义实现此crate中特质的新类型来实现额外的可组合适配器。例如，通过实现 FromReader，你可以定义一个可以从文件路径构建自己的适配器，将你的适配器嵌套到 PathTo<T> 中，例如 PathTo<YourAdapter>。