On May 3, 9:21 pm, Andy Terrel <[EMAIL PROTECTED]> wrote:
> Okay does anyone know how to decorate class member functions?
>
> The following code gives me an error:
>
> Traceback (most recent call last):
> File "decorators2.py", line 33, in <module>
> s.update()
> File "decorators2.py", line 13, in __call__
> retval = self.fn.__call__(*args,**kws)
> TypeError: update() takes exactly 1 argument (0 given)
>
> ------------------
>
> #! /usr/bin/env python
>
> class Bugger (object):
> def __init__ (self, module, fn):
> self.module = module
> self.fn = fn
>
> def __call__ (self,*args, **kws):
> ret_val = self.fn(*args,**kws)
> return ret_val
>
> def instrument (module_name):
> ret_val = lambda x: Bugger(module_name, x)
> return ret_val
>
> class Stupid:
> def __init__(self):
> self.val = 1
>
> @instrument("xpd.spam")
> def update(self):
> self.val += 1
>
> s = Stupid()
> s.update()
Second attempt. After some fuss around, I think it's just not possible
to have a class instance as a decorator. the self gets lost in
translation.
#! /usr/bin/env python
class Caller(object):
def __init__ (self, fn):
self.fn = fn
def __call__(self, *args, **kwargs):
print 'Caller calling!', repr(args)
return self.fn(*args, **kwargs)
def mydecorator(f):
return Caller(f)
class Stupid:
def __init__(self):
self.val = 1
@mydecorator
def update(self):
self.val += 1
s = Stupid()
s.update()
Caller calling! ()
Traceback (most recent call last):
File "/Users/hsoft/Desktop/foo.py", line 22, in ?
s.update()
File "/Users/hsoft/Desktop/foo.py", line 8, in __call__
return self.fn(*args, **kwargs)
TypeError: update() takes exactly 1 argument (0 given)
But why do you want to use a class? If you want to have a decorator
with argument, you only need to have something like:
def instrument(module):
def decorator(f):
def wrapper(*args, **kwargs):
print module
return f(*args, **kwargs)
return wrapper
return decorator
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