rexec: I don't seem to understand "nok_builtin_names"

[Chris Liechti]

danielm at cronus.res.cmu.edu (Dan Moskowitz) wrote in
news:39503ed5.0203281151.25d2cdda at posting.google.com: 
> Can someone tell me why execing "open" works, but not "len"?
> 
>>>> from rexec import RExec
>>>>
>>>> class MyRExec(RExec):
> ...     nok_builtin_names = RExec.nok_builtin_names + ("len",)
> ...
>>>> r = MyRExec()
>>>> print 'invisible names: '+`r.nok_builtin_names`
> invisible names: ('open', 'reload', '__import__', 'len')
>>>> r.r_exec('open')
>>>> r.r_exec("len('foo')")
> Traceback (most recent call last):
>   File "<stdin>", line 1, in ?
>   File "/usr/local/depot/python2/lib/python2.1/rexec.py", line 264, 
in
>   r_exec 
>     exec code in m.__dict__
>   File "<string>", line 1, in ?
> NameError: name 'len' is not defined

because "open" is bound to a restricted replacement function:
>>> r.r_exec('print open')
<bound method MyRExec.r_open of <__main__.MyRExec instance at 
0x010BB288>>

see the rexec documentation for more details about the restricted 
"open" the same aplies to the other builtins, they're replaced with 
limited versions.

chris


-- 
Chris <cliechti at gmx.net>