On 02/26/2018 03:41 PM, Steven D'Aprano wrote:
I have a class with a large number of parameters (about ten) assigned in
`__init__`. The class then has a number of methods which accept
*optional* arguments with the same names as the constructor/initialiser
parameters. If those arguments are None, the defaults are taken from the
instance attributes.
An example might be something like this:
class Foo:
def __init__(self, bashful, doc, dopey, grumpy,
happy, sleepy, sneezy):
self.bashful = bashful # etc
def spam(self, bashful=None, doc=None, dopey=None,
grumpy=None, happy=None, sleepy=None,
sneezy=None):
if bashful is None:
bashful = self.bashful
if doc is None:
doc = self.doc
if dopey is None:
dopey = self.dopey
if grumpy is None:
grumpy = self.grumpy
if happy is None:
happy = self.happy
if sleepy is None:
sleepy = self.sleepy
if sneezy is None:
sneezy = self.sneezy
# now do the real work...
def eggs(self, bashful=None, # etc...
):
if bashful is None:
bashful = self.bashful
# and so on
There's a lot of tedious boilerplate repetition in this, and to add
insult to injury the class is still under active development with an
unstable API, so every time I change one of the parameters, or add a new
one, I have to change it in over a dozen places.
Is there a good fix for this to reduce the amount of boilerplate?
Thanks,
def snatchit(func):
def snatched(self, *args, **kwargs):
frame = inspect.signature(func)
for name in frame.parameters:
if name != 'self':
kwargs.setdefault(name, getattr(self, name))
return func(self, *args, **kwargs)
snatched.__name__ = func.__name__
snatched.__doc__ = func.__doc__
return snatched
class Foo(object):
def __init__(self, sleepy, groggy):
self.sleepy = sleepy
self.groggy = groggy
@snatchit
def spam(self, sleepy=None):
print("I am spam. sleepy=", sleepy)
@snatchit
def ham(self, sleepy=None, groggy=None):
print("I am ham. sleepy=", sleepy, " and groggy=", groggy)
>>> f = Foo(1, 19)
>>> f.spam()
I am spam. sleepy= 1
>>> f.spam(sleepy=8)
I am spam. sleepy= 8
>>> f.ham(sleepy=8)
I am ham. sleepy= 8 and groggy= 19
>>> f.ham(sleepy=17, groggy=888)
I am ham. sleepy= 17 and groggy= 888
--
~ Jugurtha Hadjar,
--
https://mail.python.org/mailman/listinfo/python-list
