[swift-evolution] [pitch] Variadic Arguments should accept Arrays

Ricardo Parada rparada at mac.com
Thu Mar 9 12:43:54 CST 2017

In other languages I normally have a method with a variable number of arguments and another one taking an array. Then one typically ends up calling the other. 

If we had implicit splatting I imagine it would reduce such methods to only one. 

However if implicit splatting were to cause problems I think it would be nice to do it explicitly as follows:

foo(args as Argument...)

> On Feb 27, 2017, at 4:49 PM, Jose Cheyo Jimenez via swift-evolution <swift-evolution at swift.org> wrote:
>>> On Feb 27, 2017, at 1:20 PM, Tino Heth <2th at gmx.de> wrote:
>>> These is very unfortunate as a solution for “spreading” a collection or tuple so that It can be applied to function taking a variadic.
>>> It makes sense on the declaration site but not on the call site. 
>>> someFunc(@nonVariadic [1])  
>>> someFunc(@variadic [1]) 
>>> There is nothing special about variadic/ spreading that would warrant an attribute. 
>>> I think using attributes is not different than using a keyword like c# uses. 
>>> http://stackoverflow.com/questions/7580277/why-use-the-params-keyword
>>> Do we really want to tag every array/tuple with a @variadic or @nonVariadic tag when packing and unpacking parameters?
>>> variadic/ spreading (AKA packing / unpacking ) is a well known concept to most languages. 
>> I have the impression there is a misunderstanding about the proposal:
>> It would not only make the variadics-syntax superflous, but also the whole splatting-magic.
>> There would only be functions that accept arrays, and you could freely choose to feed them a comma-seperated list instead.
>> The attribute would be written in the function declaration only — and we could even decide that it isn't needed at all, and simply accept lists wherever an array is expected.
> Perhaps. Implicit splat behavior was removed for Tuples; I don’t see why we would reintroduce it for Array like constructs. 
> https://github.com/apple/swift-evolution/blob/master/proposals/0029-remove-implicit-tuple-splat.md#alternatives-considered
> I am in favor in explicit splat behavior but I don’t see it happening anytime soon. Its tagged as low priority.  
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