On 03 Oct 2005 04:47:26 -0700, Paul Rubin <http://[EMAIL PROTECTED]> wrote:
>[EMAIL PROTECTED] (Bengt Richter) writes:
>> Would you want to outlaw 'None' as an attribute name?
>> Python seems to be straddling the fence at this point:
>> >>> c.None = 'c.None'
>> SyntaxError: assignment to None
>
>Heehee, I think that's just a compiler artifact, the lexer is treating
>None as a keyword instead of a normal lexical symbol that the compiler
>treats separately. That's also why it raises SyntaxError instead of
>some other type of error. Yes, None should be ok as an attribute name.
>
Not sure whether which compiler. This one seems to differ from the C version.
>>> import compiler
>>> compiler.parse("c.None = 'c.None'")
Module(None, Stmt([Assign([AssAttr(Name('c'), 'None', 'OP_ASSIGN')],
Const('c.None'))]))
>>> compiler.compile("c.None = 'c.None'", '', 'exec')
<code object <module> at 02EE7FA0, file "", line 1>
>>> import dis
>>> dis.dis(compiler.compile("c.None = 'c.None'", '', 'exec'))
1 0 LOAD_CONST 1 ('c.None')
3 LOAD_NAME 0 (c)
6 STORE_ATTR 1 (None)
9 LOAD_CONST 0 (None)
12 RETURN_VALUE
>>> c = type('',(),{})()
>>> exec (compiler.compile("c.None = 'c.None'", '', 'exec'))
>>> c.None
'c.None'
So the compiler module is happy to generate code that you can execute,
but the builtin compiler seems not to be:
>>> c.None = 'c.None'
SyntaxError: assignment to None
and definitely not run-time:
>>> def foo():
... c.None = 'c.None'
...
File "<stdin>", line 2
SyntaxError: assignment to None
Seems like a bug wrt the intent of making compiler.compile work
exactly like the builtin C version. But maybe it has been fixed --
I am still running 2.4 from the beta I built with mingw (because
the new microsoft msi loader won't run on my version of NT4 without
upgrading that I've got too much dll hell to do on this box.
I should also upgrade mingw/msys and recompile, but I spend time here instead
;-/ )
Python 2.4b1 (#56, Nov 3 2004, 01:47:27)
[GCC 3.2.3 (mingw special 20030504-1)] on win32
Type "help", "copyright", "credits" or "license" for more information.
Regards,
Bengt Richter
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