[Python-Dev] PEP 553: Built-in debug()

[Christian Heimes]

On 2017-09-07 09:50, Barry Warsaw wrote:
> On Sep 6, 2017, at 23:10, Terry Reedy <tjreedy at udel.edu> wrote:
>>
>> Environmental variables are set to strings, not objects.  It is not clear how you intend to handle the conversion.
> 
> The environment variable names a module import path.  Without quibbling about the details of the syntax (because honestly, I’m not convinced it’s a useful feature), it would work roughly like:
> 
> * The default value is equivalent to PYTHONBREAKPOINTHOOK=pdb.set_trace
> * breakpoint() splits the value on the rightmost dot
> * modules on the LHS are imported, then the RHS is getattr’d out of that
> * That’s the callable breakpoint() calls

Setuptools' entry points [1] use colon between import and function, e.g.
"pdb:set_trace" would import pdb and then execute set_trace. The
approach can be augmented to allow calling a class method, too.

So

  "package.module:myclass.classfunc"

would do :

  from package.module import myclass
  myclass.classfunc


Regards,
Christian

[1]
https://setuptools.readthedocs.io/en/latest/setuptools.html#automatic-script-creation