Why no warnings when re-assigning builtin names?

[Philip Semanchuk]

On Aug 16, 2011, at 11:12 AM, Chris Angelico wrote:

> On Tue, Aug 16, 2011 at 3:13 PM, Philip Semanchuk <philip at semanchuk.com> wrote:
> 
>> One need look no further than the standard library to see a strong counterexample. grep through the Python source for " file =". I see dozens of examples of this builtin being used as a common variable name. I would call contributors to the standard library above-average coders, and we can see them unintentionally shadowing builtins many times.
>> 
> 
> There are several types of shadowing:
> 
> 1) Deliberate shadowing because you want to change the behavior of the
> name. Extremely rare.
> 2) Shadowing simply by using the name of an unusual builtin (like
> 'file') in a context where you never use it. Very common.
> 3) Unintentional shadowing where you create a variable, but then
> intend to use the builtin. This is the only one that's a problem.

Yes, but before you get to #3 you have to go through #2. The way I see it, #2 is setting a trap, #3 is actually stepping in it. I don't want to do either. Neither do I like working with code that has set trap #2 for me.


Cheers
Philip