[package]
name = "my_project"      # 项目名
version = "0.1.0"        # 语义化版本
edition = "2021"         # Rust 版本（2015/2018/2021/2024）
authors = ["You <you@example.com>"]
description = "我的项目"

[dependencies]
serde = "1.0"            # 添加依赖
serde_json = "1.0"
tokio = { version = "1", features = ["full"] }  # 带 feature 的依赖

cargo new my_app         # 创建二进制项目
cargo new my_lib --lib   # 创建库项目
cargo build              # 编译（debug 模式）
cargo build --release    # 编译（release 模式，优化）
cargo run                # 编译并运行
cargo check              # 只检查语法，不生成二进制（最快）
cargo test               # 运行测试
cargo doc --open         # 生成并打开文档

cargo build              # debug: 编译快，运行慢，有调试信息
cargo build --release    # release: 编译慢，运行快，优化彻底

# 产物位置
# debug:   target/debug/my_app
# release: target/release/my_app

# 方式一：命令行添加（推荐）
cargo add serde --features derive
cargo add tokio --features full

# 方式二：手动编辑 Cargo.toml

[dependencies]
serde = { version = "1", features = ["derive"] }  # 序列化
tokio = { version = "1", features = ["full"] }     # 异步运行时
reqwest = { version = "0.12", features = ["json"] } # HTTP 客户端
clap = { version = "4", features = ["derive"] }     # 命令行解析
anyhow = "1"                                        # 错误处理

cargo new cargo_practice
cd cargo_practice
cargo run

# Cargo.toml
[dependencies]
chrono = "0.4"

// src/main.rs
use chrono::Local;

fn main() {
    let now = Local::now();
    println!("当前时间: {}", now.format("%Y-%m-%d %H:%M:%S"));
}

time cargo build           # 记录 debug 编译时间
time cargo build --release # 记录 release 编译时间
time cargo check           # 记录 check 时间

# ❌ 两个库依赖同一个 crate 的不兼容版本
[dependencies]
lib_a = "1.0"  # 依赖 serde 1.0
lib_b = "2.0"  # 依赖 serde 2.0（假设不兼容）

# ✅ 解决：统一版本

// ❌ 编译错误：找不到 Serialize trait
use serde::Serialize;

// ✅ 需要在 Cargo.toml 启用 derive feature
// serde = { version = "1", features = ["derive"] }

# ❌ crate 名不能有连字符
name = "my-project"

# ✅ 用下划线
name = "my_project"