:-0
very interesting!
I've tried to run something like this:
.....................................................................
class en_property(property):
ptr_pget = None
ptr_pset = None
def pset(self, _class, value):
if (self.ptr_pset is None or type(value) == tuple):
self.ptr_pset = value[1]
self.ptr_pget = value[0]
else:
self.ptr_pset(self, _class, value)
def pget(self, _class):
return self.ptr_pget(self, _class)
def __init__(self, pget, pset):
property.__init__(self, self.pget, self.pset)
self.ptr_pget = pget
self.ptr_pset = pset
class segment():
def __new__(self):
class _segment():
def min_set(prop, self, p_min):
if (self.v_max is not None) and (p_min > self.v_max):
raise AttributeError('It must be: "min < max"')
else:
prop.v_min = p_min
def min_get(prop, self):
if 'v_min' in dir(prop):
return prop.v_min
def max_set(prop, self, p_max):
if (self.v_min is not None) and (p_max < self.v_min):
raise AttributeError('It must be: "min < max"')
else:
prop.v_max = p_max
def max_get(prop, self):
if 'v_max' in dir(prop):
return prop.v_max
def class_set(prop, self, value):
raise AttributeError('Cannot change "__class__"')
def class_get(prop, self):
class segment():
v_min, v_max = None, None
return segment
v_min = en_property(min_get, min_set)
v_max = en_property(max_get, max_set)
__class__ = en_property(class_get, class_set)
del min_get, min_set, max_get, max_set, class_get,
class_set
obj = _segment()
return obj
.....................................................................
>>> s = segment()
>>> t = segment()
>>> s.v_min, s.v_max = -1, 1
>>> t.v_min, t.v_max = 10, 20
.....................................................................
I've even override attribute __class__ (it is an property),
and code "s.__class__.v_min.v_min" raises an exception.
but we still can change the value of property using direct link:
>>> type(s).v_min.v_min = 10
I think I'm being realized that Python allows to do everything.
Maybe I will not try to find "really hidden encapsulation". :)
p.s. what do you think about the presence of two fields v_min (in
first message):
“s.__dict__['v_min']” and “s.v_min”?
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