On Sat, Apr 11, 2020 at 12:28 AM Greg Ewing <greg.ew...@canterbury.ac.nz> wrote: > > On 11/04/20 1:15 am, Chris Angelico wrote: > > > StopIteration wants to say hello :) > > By "rare' I mean as a proportion of APIs in existence. StopIteration > is frequently used, but it's just one API. > > The only other one I can think of in the stdlib is EOFError, and > that isn't even used all that much. >
AttributeError, KeyError/IndexError, and GeneratorExit (and StopAsyncIteration) want to say hi too. They're all used as a signal for "there isn't anything I could return here so I have to not return". Even if that isn't an error state, it still has to be signalled with an exception. Unless there's to be a *third* way for a function to indicate something, namely a non-value-return, but then you have to figure out how you receive that, and how you would refactor a function that is capable of returning an object or returning a lack of object. And then this third mechanism would end up looking either like exception handling, or like the return of a "package" object, eg return (True, X) for the successful return and return (False, None) for the unsuccessful. ChrisA _______________________________________________ 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/I2MMYJJA4N4LXXH6JDGHA6RSSAW2H3GX/ Code of Conduct: http://python.org/psf/codeofconduct/
