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Comment by jwells89 | Hacker News Reader

I love the internal/external labeling. With a little thought it can make for code that reads more nicely than is possible otherwise.

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JavaScript has that with:

    const hello = ({ for: person }) => `Hello ${person}`

    hello({ for: "Dorian" })

    'Hello Dorian'

Javascript's one is a little bit different in that you are renaming the destructured variable - it's not a function-specific thing - whereas Swift's version is a property of the function.

e.g.

  const user = {id: "123"};
  const { id } = user;          // This extracts the `id` field
  const { id: userId } = user;  // This also extracts the `id` field, but renames it to userId
  console.log(userId)

It does indeed, but the cost is an object allocation for every function call.

it's one of those small things that are also brilliant in hindsight

Objective-C sort of had it unofficially through how methods tended to be named.

I’m glad they found a nice way to do it in Swift.

Named parameters and nothing new and I like them. To this day I don’t understand why swift/objc have two names. I get that one is external, one internal so changing external breaks APIs. So is the only advantage that you can rename the parameter name for function implementation? So what? You can do that by a variable at the top of the function. Those two names make function signatures hard to read (which one is which etc)

crystal has it too, and i agree, it's a very nice feature

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