I suggested this before in some typing meetup, but there are a few problems with it. One is that annotating arguments as "list" or "dict" is often the wrong thing to do: instead, people should use broader, immutable types like Iterable, Sequence, or Mapping, to avoid variance problems ( https://mypy.readthedocs.io/en/stable/common_issues.html#invariance-vs-covar... ). El mar, 27 jul 2021 a las 20:13, Ignacio Pickering (<ign.pickering@gmail.com>) escribió:
Currently type hints for built-in containers are, in my opinion, less succint than required. I suspect it is probably not very difficult for a type checker to interpret something like this for example:
var1: {str: (int, int)} = {"label": (1, 2)} var2: {str} = {"other_label"}
def function(param1: {int: str} = {1: "foo"}, param2: (int, ...) = (1, 2, 3)) -> (int, (str, ...)): return 3, ("foo", "bar")
as equivalent to:
var1: dict[str, tuple[int, int]] = {"label": (1, 2)} var2: set[str] = {"other_label"}
def function(param1: dict[int, str] = (1, "foo"), param2: tuple[int, ...] = (1, 2, 3)) -> tuple[int, tuple[str, ...]]: return 3, ("foo", "bar")
I thought of posting something like this as a mypy feature suggestion, but I suspect the language would need to modify the way type annotations are interpreted for something like it to work (or maybe not?). Basically, inside a type annotation, the objects created by (a, b), [a], {a: b}, {a} would be reinterpreted as the same thing as constructing tuple[a, b], dict[a, b], list[a], set[a]. I have found myself wanting to write things like this a couple of times, so I think this overloaded usage of builtin containters is natural. I actually feel it is so natural it must either have been proposed before (in which case I would love to give the feature my +1) or there is some more or less obvious flaw. _______________________________________________ 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/SUYRV7... Code of Conduct: http://python.org/psf/codeofconduct/