Steven D'Aprano wrote:
On Mon, 9 Jun 2008 12:24:55 pm Curt Hagenlocher wrote:
So, it's okay to setattr the attribute name "None" but not okay to
set it directly?
I suspect this is off-topic for python-dev, and would be better on
comp.lang.python or similar, but for what it's worth, I consider having
an attribute named 'None' bad practise, regardless of any runtime
checks. But as part of Python's "we're all consenting adults here"
philosophy, I wouldn't approve of expensive or extensive run-time
checks specifically to prevent it. If you really have to name your
attribute None, and are prepared to live with the consequences, then go
ahead.
FWIW Curt is asking because he is on the team responsible for
implementing IronPython.
In .NET you have several enumerations with members called None, for
example 'Alignment.None'. It would be inconvenient for IronPython users
if it enforced this particular syntax rule of Python's; that not only is
assignment to None disallowed but that members named None are invalid
syntax.
The question is, what is the specification for Python. Is it that
assignment to None is disallowed and the naming of members called None
being invalid syntax is merely an artefact of the implementation of
this, or does Python require this...
Michael Foord
In a similar fashion:
class Parrot(object):
... pass
...
p = Parrot()
p.1 = 'spam'
File "<stdin>", line 1
p.1
^
SyntaxError: invalid syntax
setattr(p, '1', 'spam')
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