如何将远程板条箱的枚举序列化和反序列化为数字？

Question

我一直在尝试使用serde为 Rust 中的serialportcrate 设置以下配置，这样我就可以直观地在我的配置中提供7data_bits，但它将被反序列化为serialport::DataBits::Seven。不幸的是，当我希望它是一个数字(7(而不是一个字符串(seven(时，它似乎失败了。

测试用例

货报

[package]
name = "serde_error"
version = "0.1.0"
authors = ["Jason Miller"]
edition = "2018"
[dependencies]
serialport = "3.3.0"
serde = { version = "1.0", features = ["derive"] }
ron = "0.5.1"

以下结果会导致错误：

6:16: Expected identifier

main.rs

use serde::{Deserialize, Serialize};
#[derive(Serialize, Deserialize, Debug)]
#[serde(remote = "serialport::DataBits")]
pub enum DataBitsDef {
#[serde(rename = "5")]
Five,
#[serde(rename = "6")]
Six,
#[serde(rename = "7")]
Seven,
#[serde(rename = "8")]
Eight,
}
fn default_data_bits() -> serialport::DataBits {
serialport::DataBits::Eight
}
#[derive(Debug, Serialize, Deserialize)]
pub struct TransceiverSettings {
pub vid: u16,
pub pid: u16,
pub baud_rate: u32,
#[serde(default = "default_data_bits", with = "DataBitsDef")]
pub data_bits: serialport::DataBits,
}
impl Default for TransceiverSettings {
fn default() -> Self {
Self {
vid: 0x2341,
pid: 0x0043,
baud_rate: 115_200,
data_bits: serialport::DataBits::Eight,
}
}
}
const TRX_CONFIG: &str = "
(
vid: 0x2341,
pid: 0x0043, 
baud_rate: 9600,
data_bits: 7,
)
";
fn main() {
match ron::de::from_str::<TransceiverSettings>(&TRX_CONFIG) {
Err(e) => eprintln!("{}", e),
Ok(c) => println!("{:?}", c),
}
}

奇怪的是，写7seven成功并返回：

TransceiverSettings { vid: 9025, pid: 67, baud_rate: 9600, data_bits: Seven }

main.rs

use serde::{Deserialize, Serialize};
#[derive(Serialize, Deserialize, Debug)]
#[serde(remote = "serialport::DataBits")]
pub enum DataBitsDef {
#[serde(rename = "5")]
Five,
#[serde(rename = "6")]
Six,
#[serde(rename = "seven")]
Seven,
#[serde(rename = "8")]
Eight,
}
fn default_data_bits() -> serialport::DataBits {
serialport::DataBits::Eight
}
#[derive(Debug, Serialize, Deserialize)]
pub struct TransceiverSettings {
pub vid: u16,
pub pid: u16,
pub baud_rate: u32,
#[serde(default = "default_data_bits", with = "DataBitsDef")]
pub data_bits: serialport::DataBits,
}
impl Default for TransceiverSettings {
fn default() -> Self {
Self {
vid: 0x2341,
pid: 0x0043,
baud_rate: 115_200,
data_bits: serialport::DataBits::Eight,
}
}
}
const TRX_CONFIG: &str = "
(
vid: 0x2341,
pid: 0x0043, 
baud_rate: 9600,
data_bits: seven,
)
";
fn main() {
match ron::de::from_str::<TransceiverSettings>(&TRX_CONFIG) {
Err(e) => eprintln!("{}", e),
Ok(c) => println!("{:?}", c),
}
}

serde_repr

serde文档中给定的示例之一似乎与我的情况相关，但我还没有设法让它与我的设置一起工作。

将枚举序列化为数字
serde_reprcrate 提供了替代派生宏，这些宏派生相同的序列化和反序列化特征，但委托给类 C 枚举的基础表示形式。这允许在 JSON 中将类 C 枚举格式化为整数而不是字符串

#[derive(Serialize_repr, Deserialize_repr, PartialEq, Debug)]
#[repr(u8)]
enum SmallPrime {
Two = 2,
Three = 3,
Five = 5,
Seven = 7,
}

Answer 1

0.1.5 serde_repr中不存在对#[serde(remote)]的支持。您需要提交拉取请求或问题以添加对它的支持。

相反，请遵循如何使用 Serde 在反序列化期间转换字段？和如何使用 Serde 在序列化期间转换字段？中的建议：

use serde::{Deserialize, Serialize};
mod shim {
use serde::{de::Error, Deserialize, Deserializer, Serialize, Serializer};
use serialport::DataBits;
pub fn serialize<S>(v: &DataBits, s: S) -> Result<S::Ok, S::Error>
where
S: Serializer,
{
use DataBits::*;
let v: u8 = match v {
Five => 5,
Six => 6,
Seven => 7,
Eight => 8,
};
v.serialize(s)
}
pub fn deserialize<'de, D>(d: D) -> Result<DataBits, D::Error>
where
D: Deserializer<'de>,
{
use DataBits::*;
match u8::deserialize(d)? {
5 => Ok(Five),
6 => Ok(Six),
7 => Ok(Seven),
8 => Ok(Eight),
o => Err(D::Error::custom(format_args!("Invalid value {}", o))),
}
}
}
#[derive(Debug, Serialize, Deserialize)]
pub struct TransceiverSettings {
pub vid: u16,
pub pid: u16,
pub baud_rate: u32,
#[serde(default = "default_data_bits", with = "shim")]
pub data_bits: serialport::DataBits,
}