Question

我正在尝试读取TOML文件以创建包含带有关联值的枚举向量的结构。这是示例代码：

extern crate serde;
#[macro_use]
extern crate serde_derive;
extern crate toml;

use std::fs::File;
use std::io::Read;

#[derive(Debug, Deserialize, PartialEq)]
struct Actor {
    name: String,
    actions: Vec<Actions>,
}

#[derive(Debug, Deserialize, PartialEq)]
enum Actions {
    Wait(usize),
    Move { x: usize, y: usize },
}

fn main() {
    let input_file = "./sample_actor.toml";
    let mut file = File::open(input_file).unwrap();
    let mut file_content = String::new();
    let _bytes_read = file.read_to_string(&mut file_content).unwrap();
    let actor: Actor = toml::from_str(&file_content).unwrap();
    println!("Read actor {:?}", actor);
}

Cargo.toml

[dependencies]
serde_derive = "1.0.10"
serde = "1.0.10"
toml = "0.4.2"

sample_actor.toml

name = "actor1"
actions = [move 3 4, wait 20, move 5 6]

我知道该文件看起来“错误”，但我不知道应该如何编写TOML文件中的操作，以便crate能够将它们识别为具有X个值的枚举。

使用cargo run运行此示例时出现的错误如下：

thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: Error { inner: ErrorInner { kind: NumberInvalid, line: Some(1), col: 11, message: "", key: [] } }', /checkout/src/libcore/result.rs:906:4
note: Run with `RUST_BACKTRACE=1` for a backtrace.

我知道我可能需要为我的枚举实现FromStr以将字符串转换为我的枚举，并且我简单地知道可以实现自定义反序列化器以特定方式反序列化，但我不确定这些部分如何组合在一起。

使用serde_json代替TOML似乎是一个等效的例子（当然使用JSON文件而不是TOML）。

代码的JSON版本：

extern crate serde;
extern crate serde_json;

#[macro_use]
extern crate serde_derive;

use serde_json::Error;
use std::fs::File;
use std::io::Read;

#[derive(Debug, Serialize, Deserialize)]
enum Foo {
    bar(u32),
    baz { x: u32, y: u32 },
}

#[derive(Debug, Serialize, Deserialize)]
struct Address {
    street: String,
    city: String,
    nums: Vec<Foo>,
}

fn main() {
    /*
        let address = Address {
            street: "10 Downing Street".to_owned(),
            city: "London".to_owned(),
            nums : vec![Foo::bar(1), Foo::baz{x : 2, y : 3}],
        };

        // Serialize it to a JSON string.
        let j = serde_json::to_string(&address).unwrap();

        // Print, write to a file, or send to an HTTP server.
        println!("{}", j);
    */
    let input_file = "./sample_address.json";
    let mut file = File::open(input_file).unwrap();
    let mut file_content = String::new();
    let _bytes_read = file.read_to_string(&mut file_content).unwrap();
    let address: Address = serde_json::from_str(&file_content).unwrap();
    println!("{:?}", address);
}

此示例中读/写的JSON数据是：

Address { street: "10 Downing Street", city: "London", nums: [bar(1), baz { x: 2, y: 3 }] }

也许TOML包不能支持我的用例？

Answer 1

Serde有lots of options for serializing enums。

适合您案件的一个：

extern crate serde;
#[macro_use]
extern crate serde_derive;
extern crate toml;

#[derive(Debug, Serialize, Deserialize, PartialEq)]
#[serde(tag = "type", content = "args")]
enum Actions {
    Wait(usize),
    Move { x: usize, y: usize },
}

fn main() {
    println!("{}", toml::to_string(&Actions::Wait(5)).unwrap());

    println!("{}", toml::to_string(&Actions::Move { x: 1, y: 1 }).unwrap());
}

type = "Wait"
args = 5

type = "Move"

[args]
x = 1
y = 1

使用值将TOML反序列化为枚举向量

1 个答案: