Accessing global namespace

[John Roth]

"Dave Benjamin" <dave at 3dex.com> wrote in message
news:EApgb.18479$%o6.8797 at news1.central.cox.net...
> Carl Banks wrote:
>  > [...snip...]
> > I stand by what I said.  Using exec for anything other than explicitly
> > asking the user for Python code is wrong, incorrect, and evil, with
> > very few exceptions.  Even if it looks harmless.  Anyone who does
> > that, or advises that, should be fired.
>
> Ought I to be fired for writing something like this?
>
> #!/usr/bin/env python
>
> def attr_reader(name):
>      return '''\
> def get_%s(self):
>      return self._%s
> %s = property(get_%s)
> ''' % (name, name, name, name)
>
> class Testes:
>      _a = 42
>      exec attr_reader('a')
>
> t = Testes()
> print t.a
>
> Output: 42
>
> Dave

I didn't go through it in detail to check for safety. He was getting
after me for not emphasizing, a couple of exchanges above, that
using exec can be very unsafe unless you either construct the input
yourself, or validate the user input. It's something that's worth
remembering.

John Roth
>