On Mon, Jan 10, 2022 at 12:05 PM Steven D'Aprano <st...@pearwood.info> wrote: > > On Mon, Jan 10, 2022 at 05:39:42AM +1100, Chris Angelico wrote: > > > From my understanding, "x->y" would create a Callable if given two > > *types*, but its meaning if given two other objects is still > > undefined. > > The PEP requires parentheses around the argument list, so that would be > a SyntaxError.
That's a small restriction that makes it less clear as an operator, but sure, pretend I wrote "(x)->y" in the examples. > The PEP also states that the arrow syntax would be equivalent to calling > Callable. Callable currently enforces that the return type actually is a > type, but doesn't check the input types. > > (I don't know if that is a deliberate design or an oversight.) > > Assuming that it is an oversight, I would expect that only the following > values would be legal for the x and y objects: > > - a type; > - a string (which gets converted to a ForwardRef); > - None; > > and anything else would result in a TypeError. > TypeError is absolutely fine; it's still part of the core language syntax. >>> 1 @ 3 Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: unsupported operand type(s) for @: 'int' and 'int' If I want to create my own class that responds to matmul, I can do that, even though core data types will all TypeError; it's part of the core language and has syntactic, if not semantic, meaning in any context. ChrisA _______________________________________________ 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/6I4MFDF7R2NNJFSVZ444OLMWBBNEHFPQ/ Code of Conduct: http://python.org/psf/codeofconduct/
