There are some things about the autoassign code that bug me (mostly stylistic, but one more serious problem):
-
autoassign
does not assign an
‘args’ attribute:class Foo(object): @autoassign def __init__(self,a,b,c=False,*args): pass a=Foo('IBM','/tmp',True, 100, 101) print(a.args) # AttributeError: 'Foo' object has no attribute 'args'
-
autoassign
acts like a decorator.
Butautoassign(*argnames)
calls a
function which returns a decorator.
To achieve this magic,autoassign
needs to test the type of its first
argument. If given a choice, I
prefer functions not test
the type of its arguments. -
There seems to be a considerable
amount of code devoted to setting up
sieve
, lambdas within lambdas,
ifilters, and lots of conditions.if kwargs: exclude, f = set(kwargs['exclude']), None sieve = lambda l:itertools.ifilter(lambda nv: nv[0] not in exclude, l) elif len(names) == 1 and inspect.isfunction(names[0]): f = names[0] sieve = lambda l:l else: names, f = set(names), None sieve = lambda l: itertools.ifilter(lambda nv: nv[0] in names, l)
I think there might be a simpler way. (See
below). -
for _ in
. I don’t think
itertools.starmap(assigned.setdefault,
defaults): pass
map
orstarmap
was meant to call
functions, whose only purpose is their
side effects. It could have been
written more clearly with the mundane:for key,value in defaults.iteritems(): assigned.setdefault(key,value)
Here is an alternative simpler implementation which has the same functionality as autoassign (e.g. can do includes and excludes), and which addresses the above points:
import inspect
import functools
def autoargs(*include, **kwargs):
def _autoargs(func):
attrs, varargs, varkw, defaults = inspect.getargspec(func)
def sieve(attr):
if kwargs and attr in kwargs['exclude']:
return False
if not include or attr in include:
return True
else:
return False
@functools.wraps(func)
def wrapper(self, *args, **kwargs):
# handle default values
if defaults:
for attr, val in zip(reversed(attrs), reversed(defaults)):
if sieve(attr):
setattr(self, attr, val)
# handle positional arguments
positional_attrs = attrs[1:]
for attr, val in zip(positional_attrs, args):
if sieve(attr):
setattr(self, attr, val)
# handle varargs
if varargs:
remaining_args = args[len(positional_attrs):]
if sieve(varargs):
setattr(self, varargs, remaining_args)
# handle varkw
if kwargs:
for attr, val in kwargs.items():
if sieve(attr):
setattr(self, attr, val)
return func(self, *args, **kwargs)
return wrapper
return _autoargs
And here is the unit test I used to check its behavior:
import sys
import unittest
import utils_method as um
class Test(unittest.TestCase):
def test_autoargs(self):
class A(object):
@um.autoargs()
def __init__(self,foo,path,debug=False):
pass
a=A('rhubarb','pie',debug=True)
self.assertTrue(a.foo=='rhubarb')
self.assertTrue(a.path=='pie')
self.assertTrue(a.debug==True)
class B(object):
@um.autoargs()
def __init__(self,foo,path,debug=False,*args):
pass
a=B('rhubarb','pie',True, 100, 101)
self.assertTrue(a.foo=='rhubarb')
self.assertTrue(a.path=='pie')
self.assertTrue(a.debug==True)
self.assertTrue(a.args==(100,101))
class C(object):
@um.autoargs()
def __init__(self,foo,path,debug=False,*args,**kw):
pass
a=C('rhubarb','pie',True, 100, 101,verbose=True)
self.assertTrue(a.foo=='rhubarb')
self.assertTrue(a.path=='pie')
self.assertTrue(a.debug==True)
self.assertTrue(a.verbose==True)
self.assertTrue(a.args==(100,101))
def test_autoargs_names(self):
class C(object):
@um.autoargs('bar','baz','verbose')
def __init__(self,foo,bar,baz,verbose=False):
pass
a=C('rhubarb','pie',1)
self.assertTrue(a.bar=='pie')
self.assertTrue(a.baz==1)
self.assertTrue(a.verbose==False)
self.assertRaises(AttributeError,getattr,a,'foo')
def test_autoargs_exclude(self):
class C(object):
@um.autoargs(exclude=('bar','baz','verbose'))
def __init__(self,foo,bar,baz,verbose=False):
pass
a=C('rhubarb','pie',1)
self.assertTrue(a.foo=='rhubarb')
self.assertRaises(AttributeError,getattr,a,'bar')
def test_defaults_none(self):
class A(object):
@um.autoargs()
def __init__(self,foo,path,debug):
pass
a=A('rhubarb','pie',debug=True)
self.assertTrue(a.foo=='rhubarb')
self.assertTrue(a.path=='pie')
self.assertTrue(a.debug==True)
if __name__ == '__main__':
unittest.main(argv = sys.argv + ['--verbose'])
PS. Using autoassign
or autoargs
is compatible with IPython code completion.