On Tue, 19 Mar 2019 10:49:41 +1300 Greg Ewing <greg.ew...@canterbury.ac.nz> wrote: > Rémi Lapeyre wrote: > > > You can make "inferences from the way things are used". But the > > comparison with maths stops here, you don’t make such inferences because > > your > > object must be well defined before you start using it. > > In maths texts it's very common to see things like 'Let y = f(x)...' > where it's been made clear beforehand (either explicitly or implicitly) > what type f returns.
It's made clear because, when f was defined, it's explicitly spelled out what are the source and destination domains (not sure that's the right terminology). That's part of how you define a function in maths. There's no such thing in Python, unless you enforce typing hints and/or comprehensive docstrings. > No, you don't, because most lines in most programs allow types to > be inferred. The reason that things like MyPy are possible and > useful is that Python programs in practice are usually well-typed. You are being idealistic here. MyPy relies on typing hints being available, and sufficiently precise. Regards Antoine. _______________________________________________ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/
