On Sat, 26 Mar 2005 12:18:39 -0800, Michael Spencer
<[EMAIL PROTECTED]> wrote:
>Ron_Adam wrote:
>> Is there a way to hide global names from a function or class?
>>
>> I want to be sure that a function doesn't use any global variables by
>> mistake. So hiding them would force a name error in the case that I
>> omit an initialization step. This might be a good way to quickly
>> catch some hard to find, but easy to fix, errors in large code blocks.
>>
>> Examples:
>>
>> def a(x):
>> # ...
>> x = y # x is assigned to global y unintentionally.
>> # ...
>> return x
>>
>> def b(x):
>> # hide globals somehow
>> # ...
>> x = y # Cause a name error
>> # ...
>> return x
>>
>>
>> y = True
>>
>>
>>>>>a(False):
>>
>> True
>>
>>
>>>>>b(False):
>>
>> *** name error here ***
>>
>>
>> Ron_Adam
>>
>>
>For testing, you could simply execute the function in an empty dict:
>
> >>> a = "I'm a"
> >>> def test():
> ... print a
> ...
> >>> test()
> I'm a
> >>> exec test.func_code in {}
> Traceback (most recent call last):
> File "<input>", line 1, in ?
> File "<input>", line 2, in test
> NameError: global name 'a' is not defined
> >>>
I didn't know you could do that. Interesting. :)
I was hoping for something in line that could use with an assert
statement. But this is good too, I'll have to play around with it a
bit. Thanks.
Ron
>This would get more complicated when you wanted to test calling with
>parameters,
>so with a little more effort, you can create a new function where the globals
>binding is to an empty dict:
>
> >>> from types import FunctionType as function
> >>> testtest = function(test.func_code, {})
> >>> testtest()
> Traceback (most recent call last):
> File "<input>", line 1, in ?
> File "<input>", line 2, in test
> NameError: global name 'a' is not defined
> >>>
>
>HTH
>
>Michael
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