[Python-Dev] A Desperate Plea For Introspection (aka: BDFAP Needed)

[Yury Selivanov]

On 2012-06-22, at 3:25 PM, Christian Heimes wrote:

> Am 22.06.2012 21:10, schrieb Yury Selivanov:
>> I think that if a function lacks an annotation, that should be reflected
>> in the same way for its signature.
>> 
>> Currently:
>> 
>>    if hasattr(signature, 'return_annotation'):
>> 
>> If we use Signature.empty:
>> 
>>    if signature.return_annotation is not signature.empty:
>> 
>> So (in my humble opinion) it doesn't simplify things too much.
>> And also you can use 'try .. except AttributeError .. else' blocks,
>> which make code even more readable.
> 
> The second form has two benefits:
> 
> * you get a sensible error message when you mistype the name of the
> attribute. hasattr(signature, 'return_annotatoin') is clearly an error,
> hard to notice with the naked eye and passes silently.
> 
> * modern Python IDEs have code completion. "signature.re<TAB> is not
> signature.em<TAB>" safes key strokes.

Agree on both.

This change also cut 20 lines from the implementation.
So I guess it is a good decision after all ;)

-
Yury