[Python-ideas] "Sum" Type hinting [was: Type hinting for path-related functions]
Stephen J. Turnbull
stephen at xemacs.org
Sun May 15 13:22:53 EDT 2016
Koos Zevenhoven writes:
> I just don't want to say I broke the type hinting for os.path.*
Blame it on Brett. :-)
> But if I'm told Unions are sufficient,
Unions aren't. TypeVars are (and they're basically what you proposed
as a solution, I just didn't recognize them in the context of "Union").
> There is nothing suspicious about that Union there. "Union[str, bytes]
> -> str" is a perfectly good type hint for os.fsdecode. You can't get
> any more precise than that.
Unions are suspicious as *values*, not as arguments. Fortunately,
AnyStr is not a Union.
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