Yet another attempt at a safe eval() call

[Grant Edwards]

On 2013-01-05, Oscar Benjamin <oscar.j.benjamin at gmail.com> wrote:
> On 4 January 2013 15:53, Grant Edwards <invalid at invalid.invalid> wrote:
>> On 2013-01-04, Steven D'Aprano <steve+comp.lang.python at pearwood.info> wrote:
>>> On Thu, 03 Jan 2013 23:25:51 +0000, Grant Edwards wrote:
>>>
>>> * But frankly, you should avoid eval, and write your own mini-integer
>>>   arithmetic evaluator which avoids even the most remote possibility
>>>   of exploit.
>>
>> That's obviously the "right" thing to do.  I suppose I should figure
>> out how to use the ast module.
>
> Someone has already created a module that does this called numexpr. Is
> there some reason why you don't want to use that?

1) I didn't know about it, and my Googling didn't find it.

2) It's not part of the standard library, and my program needs to be
   distributed as a single source file.
   
-- 
Grant