> On May 5, 2017, at 8:34 AM, Vladimir.S <sva...@gmail.com> wrote:
>
> On 05.05.2017 6:12, Jose Cheyo Jimenez via swift-evolution wrote:
>> I can't think of a single time when I would need a tuple shuffle but I don't
>> really work with tuples much. It would be great to hear other people's usage
>> of this feature.
>> I did not know that types could be overloaded with values. That was very
>> surprising to me. Honestly I think that is the issue here. Not sure what can
>> be done about it.
>
>> let Int = 5 // works
>> let Void = "what?" // works.
>
> Very interesting. Could some one clarify, why this is allowed? Isn't this is
> a bug we want to fix? At least by requiring a tilda like `Int`
> And of course, you can't "overload" user defined type:
> struct S {}
> let S = 10 // Error: invalid redeclaration of ’S'
What version of swift are you using? Could it be a regression?
Welcome to Apple Swift version 3.1 (swiftlang-802.0.51 clang-802.0.41). Type
:help for assistance.
1> struct S {}
2> let S = 10
S: Int = 10
3> print(S)
error: repl.swift:3:7: error: ambiguous use of 'S'
print(S)
^
>
>> On May 4, 2017, at 7:14 PM, Robert Widmann via swift-evolution
>> <swift-evolution@swift.org <mailto:swift-evolution@swift.org>> wrote:
>>> Hi all,
>>>
>>> So sorry that this proposal comes so late in the game, but I feel it’s too
>>> important not to bring it to the attention of the community now. Attached
>>> is a proposal to deprecate a language feature many of you will probably
>>> have never had the chance to use: Tuple Shuffles. I’ve attached a copy of
>>> the first draft of the proposal below, but the latest copy can be read on
>>> Github <https://github.com/apple/swift-evolution/pull/705/files>.
>>>
>>> Thanks!
>>>
>>> ~Robert Widmann
>>>
>>>
>>> Deprecate Tuple Shuffles
>>>
>>> * Proposal: SE-NNNN
>>>
>>> <https://github.com/CodaFi/swift-evolution/blob/8eaf320b3c2a117909fc0269c398e89c033a4b9f/proposals/NNNN-filename.md>
>>> * Authors: Robert Widmann <https://github.com/codafi>
>>> * Review Manager: TBD
>>> * Status: Awaiting review
>>>
>>>
>>>
>>> <https://github.com/CodaFi/swift-evolution/blob/8eaf320b3c2a117909fc0269c398e89c033a4b9f/proposals/NNNN-deprecate-tuple-shuffles.md#introduction>Introduction
>>>
>>> This proposal seeks the deprecation of a little-known feature of Swift
>>> called a "Tuple Shuffle".
>>>
>>>
>>>
>>> <https://github.com/CodaFi/swift-evolution/blob/8eaf320b3c2a117909fc0269c398e89c033a4b9f/proposals/NNNN-deprecate-tuple-shuffles.md#motivation>Motivation
>>>
>>> A tuple-shuffle is an undocumented feature of Swift in which one can
>>> re-order the indices of a tuple by writing a pattern that describes a
>>> permutation in a syntax reminiscent of adding type-annotations to a
>>> parameter list:
>>>
>>> let a= (x:1,y:2)
>>> var b: (y:Int,x:Int)
>>> b= a
>>>
>>> It can be used to simultaneously destructure and reorder a tuple:
>>>
>>> let tuple= (first:0,second: (x:1,y:2))
>>> let (second: (x: b,y: c),first: a)= tuple
>>>
>>> It can also be used to map parameter labels out of order in a call
>>> expression:
>>>
>>> func foo(_ : (x :Int, y :Int)) {}
>>> foo((y:5,x:10))// Valid
>>>
>>> Note that a tuple shuffle is distinct from a re-assignment through a tuple
>>> pattern. For example, this series of statements will continue to function
>>> as before:
>>>
>>> var x= 5
>>> var y= 10
>>> var z= 15
>>> (z, y, x)= (x, z, y)
>>>
>>> Their inclusion in the language complicates every part of the compiler
>>> stack, uses a syntax that can be confused for type annotations
>>> <https://twitter.com/CodaFi_/status/860246169854894081>, contradicts the
>>> goals of earlier SE's (see SE-0060
>>> <https://github.com/apple/swift-evolution/blob/9cf2685293108ea3efcbebb7ee6a8618b83d4a90/proposals/0060-defaulted-parameter-order.md>),
>>> and makes non-sensical patterns possible in surprising places.
>>>
>>> Take switch-statements, for example:
>>>
>>> switch ((0,0),0){
>>> case (_ :let (y, z),_ :let s): ()// We are forbidden from giving
>>> these patterns names other than "_"
>>> default: ()
>>> }
>>>
>>> This proposal seeks to deprecate them in Swift 3 compatibility mode and
>>> enforce that deprecation as a hard error in Swift 4 to facilitate their
>>> eventual removal from the language.
>>>
>>>
>>>
>>> <https://github.com/CodaFi/swift-evolution/blob/8eaf320b3c2a117909fc0269c398e89c033a4b9f/proposals/NNNN-deprecate-tuple-shuffles.md#proposed-solution>Proposed
>>> solution
>>>
>>> Construction of Tuple Shuffle Expressions will become a warning in Swift 3
>>> compatibility mode and will be a hard-error in Swift 4.
>>>
>>>
>>>
>>> <https://github.com/CodaFi/swift-evolution/blob/8eaf320b3c2a117909fc0269c398e89c033a4b9f/proposals/NNNN-deprecate-tuple-shuffles.md#detailed-design>Detailed
>>> design
>>>
>>> In addition to the necessary diagnostics, the grammar will be ammended to
>>> simplify the following productions:
>>>
>>> tuple-pattern → (tuple-pattern-element-list <opt>)
>>> tuple-pattern-element-list → tuple-pattern-element | tuple-pattern-element
>>> , tuple-pattern-element-list
>>> - tuple-pattern-element → pattern | identifier:pattern
>>> + tuple-pattern-element → pattern
>>>
>>>
>>>
>>> <https://github.com/CodaFi/swift-evolution/blob/8eaf320b3c2a117909fc0269c398e89c033a4b9f/proposals/NNNN-deprecate-tuple-shuffles.md#impact-on-existing-code>Impact
>>> on Existing Code
>>>
>>> Because very little code is intentionally using Tuple Shuffles, impact on
>>> existing code will be negligible but not non-zero.
>>>
>>>
>>>
>>> <https://github.com/CodaFi/swift-evolution/blob/8eaf320b3c2a117909fc0269c398e89c033a4b9f/proposals/NNNN-deprecate-tuple-shuffles.md#alternatives-considered>Alternatives
>>> considered
>>>
>>> Continue to keep the architecture in place to facilitate this feature.
>>> _______________________________________________
>>> swift-evolution mailing list
>>> swift-evolution@swift.org <mailto:swift-evolution@swift.org>
>>> https://lists.swift.org/mailman/listinfo/swift-evolution
>> _______________________________________________
>> swift-evolution mailing list
>> swift-evolution@swift.org
>> https://lists.swift.org/mailman/listinfo/swift-evolution
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