Python：装饰器之有参装饰器

Posted 2020-11-14 白鹭洲

from inspect import signature

def f(a,b,c=1):pass
sig = signature(f)
sig.parameters
实现一个对被装饰的函数的参数类型检查的装饰器

 

from inspect import signature
def typeassert(*ty_args,**ty_kargs):
    def decorator(func):
        #func ->a,b
        #d = {‘a‘:int,‘b‘:str}
        sig = signature(func)
        btypes = sig.bind_partial(*ty_args,**ty_kargs).arguments
        def wrapper(*args,**kargs):
            #arg in d,instance(arg,d[arg])
            for name, obj in sig.bind(*ty_args,**ty_kargs).arguments:
                if name in btypes:
                    if not instance(obj,btyes[name]):
                        raise TypeError(‘"%s" must be "%s"‘ %(name,btyes[name]))

            return func(*args,**kargs)
        return wrapper
    return decorator

@typeassert(int,str,list)