Christopher Barker writes: > > For example, a common confusion is to identify None with NULL in > > DB, ... because most frameworks do not distinguish "Do not > > filter" and "Keep only rows where value is NULL", > > Good example— wouldn’t it be nice if all the database interaction packages > used the same Sentinel for this? In that case it would go in the DB api, > but the idea holds.
The question is whether it's an *example* of a common need, or a *nearly unique use case* of a generally useful distinction that justifies a new (semi-)singleton. Tal says that at least in the stdlib and the other cases he's seen it's almost always an application-specific need. We need to see a *list* of generally useful sentinel classes that aren't served by Tal's "_local_sentinel = Sentinel()" idiom. Otherwise such sentinels can be added ad hoc to specific (though widely used) modules as module-specific APIs. Steve _______________________________________________ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-le...@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/ZDRV5JGZSPIESIOUNWPSNAO2O3TU5FNT/ Code of Conduct: http://python.org/psf/codeofconduct/
