Steven D'Aprano <steve+comp.lang.pyt...@pearwood.info> writes: > enc = guess_encoding_from_bom("filename") > if enc == something: > # Can't guess, fall back on an alternative strategy > ... > else: > f = open("filename", encoding=enc) > > > If I forget to check the returned result, I should get an explicit > failure as soon as I try to use it, rather than silently returning the > wrong results.
Yes, agreed. > What should I return as the default default? I have four possibilities: > > (1) 'undefined', which is an standard encoding guaranteed to > raise an exception when used; +0.5. This describes the outcome of the guess. > (2) 'unknown', which best describes the result, and currently > there is no encoding with that name; +0. This *better* describes the outcome, but I don't think adding a new name is needed nor very helpful. > (3) None, which is not the name of an encoding; or −1. This is too much like a real result and doesn't adequately indicate the failure. > (4) Don't return anything, but raise an exception. (But > which exception?) +1. I'd like a custom exception class, sub-classed from ValueError. -- \ “I love to go down to the schoolyard and watch all the little | `\ children jump up and down and run around yelling and screaming. | _o__) They don't know I'm only using blanks.” —Emo Philips | Ben Finney -- https://mail.python.org/mailman/listinfo/python-list