as, abstract, break, Bool, case, catch, class, const, continue,
Rune, do, else, enum, extend, for, func, false, finally, foreign,
Float16, Float32, Float64, if, in, is, init, import, interface,
Int8, Int16, Int32, Int64, IntNative, let, mut, main, macro, match,
Nothing, open, operator, override, prop, public, package, private,
protected, quote, redef, return, spawn, super, static, struct,
synchronized, try, this, true, type, throw, This, unsafe, Unit,
UInt8, UInt16, UInt32, UInt64, UIntNative, var, VArray, where, while

// 不可变变量
let x: Int64 = 10
let y = 20  // 类型推断

// 可变变量
var count: Int64 = 0
count = count + 1

// 常量（编译时确定）
const PI = 3.14159

// 基本函数
func add(a: Int64, b: Int64): Int64 {
    return a + b
}

// 简化写法（单表达式）
func multiply(a: Int64, b: Int64): Int64 {
    a * b
}

// 泛型函数
func identity<T>(value: T): T {
    value
}

// 带默认参数
func greet(name: String, greeting: String = "Hello"): String {
    "${greeting}, ${name}!"
}

struct Rectangle {
    let width: Int64
    let height: Int64

    // 构造函数
    public init(width: Int64, height: Int64) {
        this.width = width
        this.height = height
    }

    // 主构造函数（简化写法）
    // public Rectangle(let width: Int64, let height: Int64) {}

    // 成员函数
    public func area(): Int64 {
        width * height
    }

    // 静态函数
    public static func unit(): Rectangle {
        Rectangle(1, 1)
    }
}

// 基类需要 open 修饰符才能被继承
open class Animal {
    protected var name: String

    public init(name: String) {
        this.name = name
    }

    public open func speak(): String {
        "..."
    }
}

// 继承
class Dog <: Animal {
    public init(name: String) {
        super(name)
    }

    public override func speak(): String {
        "Woof!"
    }
}

interface Drawable {
    func draw(): Unit
}

interface Resizable {
    func resize(scale: Float64): Unit
}

// 实现多个接口
class Circle <: Drawable & Resizable {
    var radius: Float64

    public init(radius: Float64) {
        this.radius = radius
    }

    public func draw(): Unit {
        println("Drawing circle with radius ${radius}")
    }

    public func resize(scale: Float64): Unit {
        this.radius = this.radius * scale
    }
}

// 简单枚举
enum Color {
    | Red | Green | Blue
}

// 带参数的枚举（代数数据类型）
enum Option<T> {
    | Some(T)
    | None
}

// 递归枚举
enum Expr {
    | Num(Int64)
    | Add(Expr, Expr)
    | Sub(Expr, Expr)
}

// 使用
let color = Color.Red
let value = Option<Int64>.Some(42)

func describe(color: Color): String {
    match (color) {
        case Red => "红色"
        case Green => "绿色"
        case Blue => "蓝色"
    }
}

// 带解构的模式匹配
func eval(expr: Expr): Int64 {
    match (expr) {
        case Num(n) => n
        case Add(left, right) => eval(left) + eval(right)
        case Sub(left, right) => eval(left) - eval(right)
    }
}

// if-let 模式
if (let Some(value) <- optionalValue) {
    println("Got value: ${value}")
}

// 自定义异常
class MyException <: Exception {
    public init(message: String) {
        super(message)
    }
}

// try-catch-finally
func riskyOperation(): Int64 {
    try {
        if (someCondition) {
            throw MyException("Something went wrong")
        }
        return 42
    } catch (e: MyException) {
        println("Caught: ${e.message}")
        return -1
    } finally {
        println("Cleanup")
    }
}

// 创建线程（协程）
let thread = spawn {
    println("Running in new thread")
}

// 等待线程完成
thread.join()

// 同步块
var counter = 0
let lock = ReentrantMutex()

func increment(): Unit {
    synchronized(lock) {
        counter = counter + 1
    }
}

// 数组
let arr: Array<Int64> = [1, 2, 3, 4, 5]
let first = arr[0]

// ArrayList（可变长数组）
var list = ArrayList<String>()
list.append("hello")
list.append("world")

// HashMap
var map = HashMap<String, Int64>()
map["one"] = 1
map["two"] = 2

// 遍历
for (item in arr) {
    println(item)
}

for ((key, value) in map) {
    println("${key}: ${value}")
}

class Temperature {
    private var _celsius: Float64 = 0.0

    // getter 和 setter
    public prop celsius: Float64 {
        get() { _celsius }
        set(value) { _celsius = value }
    }

    // 只读属性
    public prop fahrenheit: Float64 {
        get() { _celsius * 9.0 / 5.0 + 32.0 }
    }
}

// 为已有类型添加方法
extend Int64 {
    public func isEven(): Bool {
        this % 2 == 0
    }
}

// 使用
let num: Int64 = 4
println(num.isEven())  // true

// 泛型类
class Box<T> {
    private var value: T

    public init(value: T) {
        this.value = value
    }

    public func get(): T {
        value
    }
}

// 泛型约束
func compare<T>(a: T, b: T): Bool where T <: Comparable<T> {
    a < b
}

my-project/
├── cjpm.toml          # 项目配置文件
├── src/
│   └── main.cj        # 主源文件
├── test/
│   └── main_test.cj   # 测试文件
└── build/             # 构建输出

[package]
name = "my-project"
version = "1.0.0"
description = "My Cangjie Project"

[dependencies]
# 依赖配置

# 创建项目
cjpm init my-project

# 构建
cjpm build

# 运行
cjpm run

# 测试
cjpm test

# 格式化代码
cjfmt -w src/

# 代码检查
cjlint src/

// 调用 C 函数
@Foreign
foreign func printf(format: CString, ...): Int32

// 在 main 中使用
main() {
    unsafe {
        printf("Hello from C!\n".toCString())
    }
}