[swift-evolution] Proposal: Python's "in" and "not in" syntactic sugar

[Brent Royal-Gordon]

> if “hello” in [“hello, there”] { … }
> 
> if “hello” not in [“hello, there”] { … }

Swift is extremely sparing with keywords in operator position; the only ones I can think of off the top of my head are `is` and `as`, and even those aren’t actually operators. You’re proposing to introduce one as syntactic sugar for [array].contains(elem), and introduce an even more bizarre two-word operator for ![array].contains(elem). I don’t think that’s gonna fly.

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Brent Royal-Gordon
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