On Tue, Oct 6, 2020 at 9:35 PM Steven D'Aprano <st...@pearwood.info> wrote:
> On Tue, Oct 06, 2020 at 09:30:06AM -0700, aleksiy123 wrote: > > Currently there are a few Protocols > > https://docs.python.org/3/library/typing.html#protocols defined in the > > typing module. One that I recently felt like was missing was a typing > > annotation for classes with a __str__() method defined. Seems like a > fairly > > straightforward implementation. > > > Why do you care specifically about the `__str__` dunder? Calling str() > is one of those protocols that should always succeed, whether the > argument defines `__str__`, `__repr__`, or inherits from object. > > Ignoring the possibility of bugs or deliberate raising, I can't think of > any object that doesn't support the str() protocol. Have I missed > anything? > > > > -- > Steve > I was also finding this desire a little puzzling (and thought it might just be my inexperience). And since both `type` and `object` have a __str__ method*, it seems like the only way any object could NOT support the str() protocol would be to write a __str__ method and deliberately bust it. Right? Is there even a way to create a python object that does not have `__str__` in the MRO? Seeing as that is the case, and seeing as how the protocol system can't look inside your __str__ method to find out whether it is busted at type checking time, isn't `Any` all you'll ever need to type-hint the __str__ protocol? * and upon checking in fact it is the same __str__ method --- Ricky. "I've never met a Kentucky man who wasn't either thinking about going home or actually going home." - Happy Chandler
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