On Tue, 30 Dec 2008 15:35:28 -0600, Rob Williscroft wrote:
> Stef Mientki wrote in news:mailman.6399.1230668197.3487.python-
> l...@python.org in comp.lang.python:
>
>>>> And, by the way, exec is a *statement*, not a function!
>>>>
>> exec ( Init_Code, PG.P_Globals )
>>
>> I've really doubt that this is a statement, unless I don't understand
>> what a statement is.
>>>>
>>>>
>>
> In python 2.x the above is a statement that is passed a tuple:
>
> http://docs.python.org/reference/simple_stmts.html#exec
The documentation doesn't say anything about it accepting a tuple as an
argument. The tuple argument works in both 2.5 and 2.6. Curious.
I was also surprised by this behaviour:
>>> g, l = {}, {} # no globals, no locals
>>> exec "x = 1" in g, l
>>> l
{'x': 1}
>>> g.keys()
['__builtins__']
I see *now* that this is documented:
"...the current implementation MAY add a reference to the dictionary of
the built-in module __builtin__ under the key __builtins__ (!)."
[emphasis added]
but it's still rather disconcerting. That means that:
exec "some potentially dangerous code" in {}, {}
isn't as safe as I thought it was.
--
Steven
--
http://mail.python.org/mailman/listinfo/python-list
