在python3中，可以使用函数注解，类似这样：
代码语言：javascript复制def print(input :str) -> int:
pass函数注解可以用内置方法获取，所以可以利用这个特性做一个类型检验的装饰器。 代码如下：
代码语言：javascript复制import functools
import inspect
def typeassert(fn):
"""
provide type assert, examples:
#normal
@typeassert
def hello(name: str):
return name "world"
#check return
@typeassert
def hello2(name: str, count: int=5) -> (int, int, int):
print("{} {} say hello".format(count, name))
return 0, 1, 2
:param fn:input funcs
:return:
"""
@functools.wraps(fn)
def wrap(*args, **kwargs):
sig = inspect.signature(fn)
parameters = sig.bind_partial(*args, **kwargs).arguments.items()
anno = fn.__annotations__
for element_name, value in parameters:
if element_name in anno:
if not isinstance(value, anno[element_name]):
raise TypeError(
"{}:{} type not {}".format(element_name, value, anno[element_name])
)
ret = fn(*args, **kwargs)
if 'return' not in anno:
return ret
anno_return = anno['return']
if isinstance(anno_return, type):
if not isinstance(ret, anno_return):
raise TypeError("return value {} != {}".format(ret, anno_return))
elif isinstance(anno_return, (list, tuple)):
if len(ret) != len(anno_return):
raise TypeError("return value count {} != {}".format(len(ret), len(anno_return)))
for key, ret_value in enumerate(ret):
if not isinstance(ret_value, anno_return[key]):
raise TypeError(
"return value index:{}({}) type not {}".format(key, ret_value, anno_return[key])
)
return ret
return wrap
