python - Decorator that adds a keyword parameter -

i'm trying define decorator adds 1 keyword argument decorated function f. f might have combination of (positional, keyword, etc) parameters. tried this:

def capture_wrap(f):     def captured(name=false, *args, **kwargs):         """name can false, true or str. if str, use name."""         print (name, f, args, kwargs)         inner = f(*args, **kwargs)         if name false:             return inner         elif name true:             return capture(inner)         else:             return capture(inner, name=name)     return captured 

if try use function accepts single argument:

@capture_wrap def any_of(s):     """s must in right format.     see https://docs.python.org/3/library/re.html#regular-expression-syntax ."""     return wrap('[', dinant(s, escape=false), ']') 

0-9a-fa-f <function any_of @ 0x7fb370548a60> () {} traceback (most recent call last): file "./dinant.py", line 222, in <module>     hex = one_or_more(any_of('0-9a-fa-f')) file "./dinant.py", line 116, in captured     inner = f(*args, **kwargs) typeerror: any_of() missing 1 required positional argument: 's' 

i error because argument becomes name parameter in captured(). how should correctly?

you can make name keyword-only argument achieve this. issue is positional argument , when you're doing any_of('foo') 'foo' being passed name argument.

def capture_wrap(f):     def captured(*args, name=false, **kwargs):         """name can false, true or str. if str, use name."""         print(name, f, args, kwargs)         inner = f(*args, **kwargs)         return inner     return captured   @capture_wrap def any_of(s1, s2, s3, **kwargs):     return "i something" 

demo:

>>> any_of('0-9a-fa-f', 1, 2) false <function any_of @ 0x1041daea0> ('0-9a-fa-f', 1, 2) {} 'i something'  >>> any_of('0-9a-fa-f', 2, 3, a=1, b=2, name='some-name') some-name <function any_of @ 0x1041daea0> ('0-9a-fa-f', 2, 3) {'a': 1, 'b': 2} 'i something'