[swift-evolution] [Proposal][Discussion] Deprecate Tuple Shuffles

[Adrian Zubarev]

Just to double check, here is the updated version of my code snippet on how it would look like if this proposal will be accepted.

let a: (x: Int, y: Int) = (1, 2)
var b: (y: Int, x: Int) = a
Label swap while destructuring:

let tuple: (first: Int, second: (x: Int, y: Int)) = (0, (1, 2))

let (first: a, second: (x: b, y: c)): (first: Int, second: (x: Int, y: Int)) = tuple // fine, unaffected

let (second: (x: b, y: c), first: a): (second: (x: Int, y: Int), first: Int) = tuple // will the rendering be banned or not?
Is this correct now?



-- 
Adrian Zubarev
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Am 5. Mai 2017 um 07:53:51, Xiaodi Wu (xiaodi.wu at gmail.com) schrieb:

On Fri, May 5, 2017 at 12:52 AM, Adrian Zubarev <adrian.zubarev at devandartist.com> wrote:
Eliminating all labels would mean that even the first example from my last post will be banned.

No, not eliminating all labels from tuples, but from tuple _patterns_.
 
Is there any difference from labels in tuple types and labels in tuples themselves?

Personally I would not support the removal of labels from tuple types, because it’s a very useful feature that replaces indexed access like myTuple.1 to a more readable counterpart myTuple.somethingSpecial.

Am I still missing something out?



-- 
Adrian Zubarev
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Am 5. Mai 2017 um 07:43:49, Xiaodi Wu (xiaodi.wu at gmail.com) schrieb:

On Fri, May 5, 2017 at 12:42 AM, Adrian Zubarev via swift-evolution <swift-evolution at swift.org> wrote:
Okay now I see where this is going. So basically you want to mirror the behavior of function parameters into tuples.

You might want to be a little bit more explicit on types in your proposal to better understand the so called ‘tuple shuffle’.

let a: (x: Int, y: Int) = (x: 1, y: 2)
var b: (y: Int, x: Int) = a
a.x == b.x
a.y == b.y
Label swap (tuple shuffle) while destructuring:

let tuple: (first: Int, second: (x: Int, y: Int)) = (first: 0, second: (x: 1, y: 2))

let (first: a, second: (x: b, y: c)): (first: Int, second: (x: Int, y: Int)) = tuple // fine, unaffected

let (second: (x: b, y: c), first: a): (second: (x: Int, y: Int), first: Int) = tuple // shuffle => error

No, I thought this was what Robert was proposing, but he is proposing the elimination of all labels in tuple patterns. Your second example would be banned.


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