From the Decorators for Functions and Methods:
Python 2
def accepts(*types):
def check_accepts(f):
assert len(types) == f.func_code.co_argcount
def new_f(*args, **kwds):
for (a, t) in zip(args, types):
assert isinstance(a, t),
"arg %r does not match %s" % (a,t)
return f(*args, **kwds)
new_f.func_name = f.func_name
return new_f
return check_accepts
Python 3
In Python 3 func_code
has changed to __code__
and func_name
has changed to __name__
.
def accepts(*types):
def check_accepts(f):
assert len(types) == f.__code__.co_argcount
def new_f(*args, **kwds):
for (a, t) in zip(args, types):
assert isinstance(a, t),
"arg %r does not match %s" % (a,t)
return f(*args, **kwds)
new_f.__name__ = f.__name__
return new_f
return check_accepts
Usage:
@accepts(int, (int,float))
def func(arg1, arg2):
return arg1 * arg2
func(3, 2) # -> 6
func('3', 2) # -> AssertionError: arg '3' does not match <type 'int'>
arg2
can be either int
or float
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…