# 1. f-strings（格式化字符串）
name = "程序员晚枫"
print(f"我是{name} ！")  # 输出：我是程序员晚枫


# 2. 变量类型注解
def greet(name: str) -> str:
    return f"Hello, {name}"


# 3. 异步生成器和推导式
async def async_gen():
    for i in range(3):
        yield i
        await asyncio.sleep(1)

from dataclasses import dataclass
from typing import List


# 1. 数据类
@dataclass
class User:
    name: str
    age: int
    emails: List[str] = None

    def __post_init__(self):
        if self.emails is None:
            self.emails = []


# 2. 内置breakpoint()
def debug_demo():
    x = 42
    breakpoint()  # 进入调试器
    return x * 2


# 3. 模块级别的__getattr__
def __getattr__(name: str):
    if name == "new_feature":
        return "动态属性"

# 1. 海象运算符 :=
if (n := len([1, 2, 3])) > 2:
    print(f"列表长度是{n}")  # 列表长度是3


# 2. 位置参数
def f(a, b, /, c, d, *, e, f):
    # /前的参数必须位置传参，*后的参数必须关键字传参
    return a + b + c + d + e + f


# 3. f-string调试
user = "程序员晚枫"
print(f"{user=}")  # 输出：user='程序员晚枫'

# 1. 字典合并运算符
dict1 = {"a": 1, "b": 2}
dict2 = {"b": 3, "c": 4}
merged = dict1 | dict2  # {'a': 1, 'b': 3, 'c': 4}

# 2. 字符串方法
"hello world".removeprefix("hello ")  # "world"
"程序员晚枫.py".removesuffix(".py")  # "程序员晚枫"

# 3. 类型提示泛化
from collections.abc import Sequence
from typing import Union


def process_items(items: Sequence[Union[int, str]]) -> None:
    pass

# 1. 结构模式匹配
def handle_command(command):
    match command.split():
        case ["quit"]:
            print("退出程序")
        case ["load", filename]:
            print(f"加载文件: {filename}")
        case ["save", filename, *rest]:
            print(f"保存到: {filename}")
        case _:
            print("未知命令")


# 2. 更清晰的错误信息
# 旧的错误：TypeError: unsupported operand type(s) for +: 'int' and 'str'
# 新的错误：TypeError: can only concatenate str (not "int") to str

# 3. 联合类型运算符
def parse_number(value: int | float | str) -> float:
    return float(value)

# 1. 异常组
try:
    raise ExceptionGroup(
        "多个错误",
        [ValueError("错误1"), TypeError("错误2")]
    )
except* ValueError as eg:
    print(f"捕获到ValueError: {eg.exceptions}")
except* TypeError as eg:
    print(f"捕获到TypeError: {eg.exceptions}")

# 2. Self类型
from typing import Self


class Database:
    def connection(self) -> Self:
        return self


# 3. 字面量字符串
from typing import Literal


def set_mode(mode: Literal["read", "write"]) -> None:
    pass

# 1. 类型参数语法
def max[T](args: list[T]) -> T:
    return max(args)


class Container[T]:
    def __init__(self, value: T):
        self.value = value


# 2. f-string改进
name = "程序员晚枫a"
print(f"{name=}")  # name='程序员晚枫'
print(f"{name.upper()=}")  # name.upper()='程序员晚枫A'

# 3. 子解释器API
import interpreters

interp = interpreters.create()
interp.run("print('Hello from subinterpreter')")

import interpreters


# 1. 多解释器 - 突破GIL限制
def run_parallel():
    interp = interpreters.create()
    code = """
import time
result = sum(i*i for i in range(10**6))
print(f"计算结果: {result}")
"""
    interp.exec(code)


# 2. 注解延迟求值
class User:
    def set_manager(self, manager: User) -> User:  # 前向引用
        return self


# 3. 模板字符串
from string.templatelib import Template

user_input = ""
template = t"

{user_input}

"


def safe_render(template: Template) -> str:
    import html
    return html.escape(str(template))