> This is neat. :) Could that maybe be extended to only assign selected
> args to the instance and let others pass unchanged. So that, for instance:
>
> @autoassign("foo", "bar")
> def __init__(self, foo, bar, baz):
> super(baz)
I've seen some folks import inspect/functools, but from my
testing, the __init__ method in question has a .func_code object
that already has the varnames in it. However, as you suggest, a
version below allows for named defaults, and letting others go
un-defaulted. I'm not sure about naming conventions for
class-style decorators--start with a cap, like a class should
("AutoAssign") or because it behaves like a function, use
"auto_assign", or any of a number of other variants. Anyways...
class auto_assign(object):
def __init__(self, *varnames):
self.args = set(varnames)
def __call__(self, fn):
autoassign = self
def wrapper(self, *args, **kwargs):
for argname, argvalue in zip(
fn.func_code.co_varnames[1:],
args):
if argname in autoassign.args:
setattr(self, argname, argvalue)
for argname in autoassign.args:
if argname in kwargs:
setattr(self, argname, kwargs[argname])
fn(self, *args, **kwargs)
return wrapper
class Foo(object):
@auto_assign('foo', 'baz', 'fred')
def __init__(self, foo, bar, baz, *args, **kwargs):
pass
f = Foo('hello', 42, 3.14, fred='wilma', barney='betty')
try:
print f.foo
except AttributeError:
print "Could not print f.foo"
try:
print f.bar
except AttributeError:
print "Could not print f.bar"
try:
print f.baz
except AttributeError:
print "Could not print f.baz"
try:
print f.fred
except AttributeError:
print "Could not print f.fred"
try:
print f.barney
except AttributeError:
print "Could not print f.barney"
-tkc
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