Great timing! Last week I was trying to emulate a certain Rust example in Python. Rust has a way to implement families of classes without subclassing, which I think could be a great addition to Python someday. I'll explain below.
Here is a Rust example (https://youtu.be/WDkv2cKOxx0?t=3795) that demonstrates a way to implement classes without subclassing. # Rust Code enum Shape { Circle(f32), Square(f32), Rectangle(f32, f32) } impl Shape { fn area(self) -> f32 { match self { Shape::Circle(r) => 3.1 * r * r, Shape::Square(l) => l * l, Shape::Rectangle(l, w) => l * w } } } fn main () { let c = Shape::Circle(3.0); let s = Shape::Square(3.0); let r = Shape::Rectangle(3.0, 7.5); println!("○ {}", c.area()); println!("□ {}", s.area()); println!("▭ {}", r.area()); } # Output ○ 27.899998 □ 9 ▭ 22.5 The general idea is: - declare classes that share a certain type - extend common methods with a match-case style That's it. No sub-classing required. I wondered if someday, can we do this in Python? This match-case proposal seems to fit well in this example. While I know this PEP does not focus on detailed applications, does anyone believe we can achieve elegant class creation (sans subclassing) with match-cases? On Wed, Jun 24, 2020 at 2:04 PM Guido van Rossum <gu...@python.org> wrote: > On Tue, Jun 23, 2020 at 11:27 PM Emily Bowman <silverback...@gmail.com> > wrote: > > I wonder if it's time to officially designate _ as a reserved name. > > Alas, it's too late for that. The i18n community uses _("message text") to > mark translatable text. You may want to look into the gettext stdlib module. > > -- > --Guido van Rossum (python.org/~guido) > *Pronouns: he/him **(why is my pronoun here?)* > <http://feministing.com/2015/02/03/how-using-they-as-a-singular-pronoun-can-change-the-world/> > _______________________________________________ > Python-Dev mailing list -- python-dev@python.org > To unsubscribe send an email to python-dev-le...@python.org > https://mail.python.org/mailman3/lists/python-dev.python.org/ > Message archived at > https://mail.python.org/archives/list/python-dev@python.org/message/P6EKIKFP6MX2N2KVFFCF4XUVVMSJ6Q5B/ > Code of Conduct: http://python.org/psf/codeofconduct/ >
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