A4 portrait - PET: Python Entre Todos - Python Argentina

Decorator functions without arguments 30
)
return wrap
@disable
def yes(string='y', end='\n'):
[...]
Decorator functions without arguments
In a decorator function that doesn’t receive arguments, its first and only parameter is
the callable to be decorated. In the nested function is where decorated callable
positional and keyword arguments are received.
This can be seen in any of previous examples.
Decorator functions with arguments
Now we’ll look an example of a decorator function that receives arguments. The
example will be based on our previous log_callable and will allow us to specify if we
really want to count the number of calls.
log_callable with arguments example:
def log_callable(do_count):
if not getattr(log_callable, 'count_dict', None) and do_count:
log_callable.count_dict = {}
if do_count:
log_callable.count_dict.setdefault(
callable.__name__, 0
)
def wrap(callable):
def inner_wrap(*args, **kwargs):
callable(*args, **kwargs)
message = []
if do_count:
log_callable.count_dict.setdefault(
callable.__name__, 0
)
log_callable.count_dict[callable.__name__] += 1
message.append(
u"""called: '{0}' '{1} times'""".format(
callable.__name__,
log_callable.count_dict[callable.__name__],
)
)
else:
message.append(u"""called: '{0}'""".format(callable.__name__))
message.append(u"""Arguments: {0}""".format(", ".join(args)))
message.append(
u"""Keyword Arguments: {0}""".format(
", ".join(["{0}={1}".format(key, value) \
for (key, value) in kwargs.items()])
)
)
logging.debug("; ".join(message))
PET: English Translation (Issue 1, August 2010) — http://revista.python.org.ar