Terry Hancock wrote:
> Frankly, I was surprised this worked at all, but I tried
> creating a property outside of a class (i.e. at the module
> level), and it seems to behave as a property:
Not so surprising. Making a class begins by making a little namespace,
then using it to build the class. If you look at how class construction
works, it gets handed the namespace to wrap parts (the originals are
left alone). After playing with your example for a little, perhaps
the following will illustrate things:
def get_x(obj):
return thevar
def set_x(obj, val):
global thevar
thevar = val
def del_x(obj):
global thevar
del thevar
def textify(obj):
objid = '%s_%s' % (obj.__class__.__name__, id(obj))
try:
return '%s:%r' % (objid, thevar)
except (NameError, AttributeError):
return '%s:---' % objid
prop = property(get_x, set_x, del_x)
class One(object):
x = prop
__repr__ = textify
class Two(object):
y = prop
__str__ = textify
Class Three(object):
__repr__ = textify
a = One()
b = Two()
c = Three()
print a, b, c
a.x = 5
print a.x, b.y, a, b, c
Three.z = One.x
print c, c.z
del b.y
print a, b, c
print a.x
You may want to raise AttributeError on get_x (you have no name to use):
def get_x(obj):
try:
return thevar
except NameError:
raise AttributeError
> Am I about to shoot myself in the foot?
Well, usually all this playing is good for understanding how Python
works, but makes your connections less than explicit, and we know
that explicit is better than implicit.
--Scott David Daniels
[EMAIL PROTECTED]
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