Reply to thread

Message

[QUOTE="Jeremy Bowers, post: 1809358"]
I'm going to echo Steven's comment: "What's the situation in which you
think you want different properties for different instances of the same
class?"

Another thought would be a custom __setattr__ and a bit of support:

Python 2.3.5 (#1, Mar  3 2005, 17:32:12) 
[GCC 3.4.3  (Gentoo Linux 3.4.3, ssp-3.4.3-0, pie-8.7.6.6)] on linux2
Type "help", "copyright", "credits" or "license" for more information.....     def __init__(self):
....             self.__dict__['_readOnly'] = sets.Set()
....     def addReadOnly(self, key, value):
....             setattr(self, key, value)
....             self._readOnly.add(key)
....     def __setattr__(self, key, value):
....             if key in self._readOnly:
....                     raise AttributeError("can't set attribute")
....             self.__dict__[key] = value
.... Traceback (most recent call last):
  File "<stdin>", line 1, in ?
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
  File "<stdin>", line 5, in addReadOnly

I don't guarantee this completely fits the bill but I'm sure you can adapt
it from here.

Also note that, strictly speaking, you can't make a "true" read-only
attribute, only one that alerts a programmer if they try the simple way.
In a pure-Python object, there is always a way in. This shouldn't worry
you if you're using Python ("We're all consenting adults here"), but you
should also be aware of that. That said, this is certainly useful in the
real world.
[/QUOTE]

Verification