gh-105578: Add more usage examples to typing.AnyStr docs (#107045) · python/cpython@f877b32 (original) (raw)
``` @@ -849,6 +849,21 @@ using [].
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` concat(b"foo", b"bar") # OK, output has type 'bytes'
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` concat("foo", b"bar") # Error, cannot mix str and bytes
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Note that, despite its name, ``AnyStr`` has nothing to do with the
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:class:`Any` type, nor does it mean "any string". In particular, ``AnyStr``
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and ``str | bytes`` are different from each other and have different use
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cases::
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Invalid use of AnyStr:
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The type variable is used only once in the function signature,
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so cannot be "solved" by the type checker
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def greet_bad(cond: bool) -> AnyStr:
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return "hi there!" if cond else b"greetings!"
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The better way of annotating this function:
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def greet_proper(cond: bool) -> str | bytes:
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return "hi there!" if cond else b"greetings!"
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`.. data:: LiteralString
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` Special type that includes only literal strings.
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