On 10/27/2011 6:52 PM, candide wrote:
No but I'm expecting from Python documentation to mention the laws of
Python ...
The details of CPython builtin classes are not laws of Python. It *is* a
'law of Python' that classes can use 'slots = ' to restrict the
attributes of instances. By implication, builtin classes in any
implementation do not have to allow attribute assignment. I do not
believe it would be a violation if some implementation did so.
None of this is to say that we could not say something on the subject at
the beginning of the 'built-in types' chapter of the lib manual.
OK but I'm talking about classes, not instances :
Yes you are. The class determines whether its instances have assignable
new attributes.
> 42 has no __dict__ > attribute but,
> may be, 43 _has_ such attribute, who knows in advance ? ;)
True, in a sense, but if the class allowed a user to execute
"42.__dict__ = {}" then you could safely assume that "43.xxx = z" should
work also.
--
Terry Jan Reedy
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