
I really like this idea. Once you've already decided to raise an exception, does it really cost much to try to raise a more helpful one? And helpful exception messages make programming a lot less painful, and a lot more of a joy. On Tue, Oct 22, 2019 at 2:43 PM Mike Miller <python-ideas@mgmiller.net> wrote:
On 2019-10-18 10:23, Ricky Teachey wrote:
but i'm -0 because i am very concerned it will not be obvious to new learners, without constantly looking it up, whether adding two mappings together would either:
The big trade off I'm gathering from this mega-thread is that the |, |= operators are more accurate, but less obvious to newcomers, who will first try +, += instead.
I've tried them in this order myself several times over the years.
Had an idea, why not choose the more accurate syntax: |, |= after all? Then, to help newcomers and forgetful pros a custom error message is implemented for +, +=. In pseudo C/Python, something like this:
class dict:
def __add__(self, other):
if isinstance(other, dict): raise TypeError( 'unsupported operand type(s) for +: … ' 'Dictionary merging leads to last-value-wins data ' 'loss. If acceptable, use the union "|" operator.' ) else: raise TypeError(std_err_msg)
I think it is worth it to lead the newcomer to a moment's reflection on why dictionary combining/merging is potentially lossy. Everyone is informed with the proper mental model, then on their way and left alone afterward.
Thoughts? -Mike _______________________________________________ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-leave@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/43T52R... Code of Conduct: http://python.org/psf/codeofconduct/
--
--- You received this message because you are subscribed to a topic in the Google Groups "python-ideas" group. To unsubscribe from this topic, visit https://groups.google.com/d/topic/python-ideas/puGRBmzVl9c/unsubscribe. To unsubscribe from this group and all its topics, send an email to python-ideas+unsubscribe@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/python-ideas/3ac803c4-f703-67bf-c4c9-a37bb... .