Re: interactive execution
Jive Dadson wrote:
Yeah. I got it.
exec foo = 555 in globals(), locals() does the trick.
You can do it with your own dicts, too -- but they must already exist,
exec doesn't create them out of nowhere.
myglobals = {'a':2, 'b':5}
mylocals = {'c': 3}
exec d = a * b + c in myglobals, mylocals
myglobals
{'a': 2, '__builtins__': {...}, 'b': 5}
mylocals
{'c': 3, 'd': 13}
This gives you some control over what the exec'ed statement actually
sees, as well as what happens with the results. (But as I mentioned
before, there is no real security here if you're exec'ing arbitrary
code -- there's no sandboxing involved, and the exec'ed string *can*
use that __builtins__ reference (among other things) to do all sorts
of malicious stuff.)
Jeff Shannon
Technician/Programmer
Credit International
--
http://mail.python.org/mailman/listinfo/python-list
interactive execution
How does one execute arbitrary text as code within a module's context? I've got some code that compiles some text and then executes it. When the string is print 'Hello', it prints Hello. I get no exception when I compile and execute foo = 555. If I then compile and exec print foo, I get a name error. The variable foo is undefined. My assumption is that the exec command created a new namespace, put foo in that namespace, and then threw the namespace away. Or something. I know it must be possible to do this, because it's exactly what programs like IDLE do. Thankee. -- http://mail.python.org/mailman/listinfo/python-list
Re: interactive execution
Jive Dadson wrote: How does one execute arbitrary text as code within a module's context? I've got some code that compiles some text and then executes it. When the string is print 'Hello', it prints Hello. I get no exception when I compile and execute foo = 555. If I then compile and exec print foo, I get a name error. The variable foo is undefined. My assumption is that the exec command created a new namespace, put foo in that namespace, and then threw the namespace away. Or something. You can do exec codestring in globaldict, localdict (Or something like that, this is from unused memory and is untested.) The net effect is that exec uses the subsequent dictionaries as its globals and locals, reading from and writing to them as necessary. (Note that this doesn't get you any real security, because malicious code can still get to __builtins__ from almost any object...) Jeff Shannon Technician/Programmer Credit International -- http://mail.python.org/mailman/listinfo/python-list
Re: interactive execution
Jive Dadson wrote:
I've got some code that compiles some text and then executes it. When
the string is print 'Hello', it prints Hello. I get no exception
when I compile and execute foo = 555. If I then compile and exec
print foo, I get a name error. The variable foo is undefined. My
assumption is that the exec command created a new namespace, put foo
in that namespace, and then threw the namespace away. Or something.
I know it must be possible to do this, because it's exactly what
programs like IDLE do.
exec statement in name_space
will do the trick.
d = {}
exec 'foo=555' in d
d['foo']
555
exec print foo in d
555
- george
--
http://mail.python.org/mailman/listinfo/python-list
Re: interactive execution
Jeff Shannon wrote: Jive Dadson wrote: How does one execute arbitrary text as code within a module's context? I've got some code that compiles some text and then executes it. When the string is print 'Hello', it prints Hello. I get no exception when I compile and execute foo = 555. If I then compile and exec print foo, I get a name error. The variable foo is undefined. My assumption is that the exec command created a new namespace, put foo in that namespace, and then threw the namespace away. Or something. You can do exec codestring in globaldict, localdict (Or something like that, this is from unused memory and is untested.) The net effect is that exec uses the subsequent dictionaries as its globals and locals, reading from and writing to them as necessary. (Note that this doesn't get you any real security, because malicious code can still get to __builtins__ from almost any object...) Jeff Shannon Technician/Programmer Credit International Promising, but, Traceback (most recent call last): File F:/C++ Projects/zardude/temp.py, line 9, in -toplevel- exec foo = 555 in globaldict, localdict NameError: name 'globaldict' is not defined -- http://mail.python.org/mailman/listinfo/python-list
Re: interactive execution
Yeah. I got it. exec foo = 555 in globals(), locals() does the trick. -- http://mail.python.org/mailman/listinfo/python-list
