python - Python 2 中的类型提示

Question

在 PEP 484 , 类型提示被添加到 Python 3 中并包含 typing模块。有没有办法在 Python 2 中做到这一点？我能想到的只是有一个装饰器来添加到检查类型的方法中，但这会在运行时失败，并且不会像提示允许的那样更早被捕获。

Answer 1

根据Suggested syntax for Python 2.7 and straddling code在定义类型提示的 PEP 484 中，有一种与 Python 2.7 兼容的替代语法。但是它不是强制性的，所以我不知道它的支持程度，但引用 PEP:

Some tools may want to support type annotations in code that must be compatible with Python 2.7. For this purpose this PEP has a suggested (but not mandatory) extension where function annotations are placed in a # type: comment. Such a comment must be placed immediately following the function header (before the docstring). An example: the following Python 3 code:

def embezzle(self, account: str, funds: int = 1000000, *fake_receipts: str) -> None:
    """Embezzle funds from account using fake receipts."""
    <code goes here>

is equivalent to the following:

def embezzle(self, account, funds=1000000, *fake_receipts):
    # type: (str, int, *str) -> None
    """Embezzle funds from account using fake receipts."""
    <code goes here>

关于 mypy 支持，请参阅 Type checking Python 2 code .