Chained constraints

[adriangb]

Thought from #28: we could also do something like Exponent = Annotated[int, Gt(0) & MultipleOf(2)].

Implementing & would be easy: it just creates a GroupedMetadata.

Other operators would be trickier: Annotated[str, Foo | Bar] should actually be expressed as Annotated[str, Bar] | Annotated[str, Foo], and I have no idea what XOR would be, I think we’d have to offload that to implementers. So I think this idea has short legs.

[adriangb]

Also as “pretty” as & seems, it’s not saving any typing.

[Zac-HD]

Yeah, & can just be spelled ,; I agree that | should be expressed outside the Annotated[], and I don't think that xor is even expressible in Python types at the moment (without high-grade magic, anyway).