[swift-evolution] Make the first parameter in a function declaration follow the same rules as the others

[Pierre Monod-Broca]

I'm not for mandatory parameter names, it doesn't always make sense to have them. Besides I don't see much value in removing the commas or reordering the parameters.

By the way how would you do for variadics parameters ?

Pierre

> Le 12 mars 2016 à 21:18, Ted F.A. van Gaalen via swift-evolution <swift-evolution at swift.org> a écrit :
> 
> oops !! Errata:
> in my examples something went wrong:  here they are again, corrected:
> 
>> Always specifying  labels/names allows us also to have a simpler function syntax as well like so:
>> 
>>        bookList.insert( element: book  reorderBy: .authorName  dropOldVersions: true)       // no comma separators
>> 
>> or formatted like this for clarity : 
>> 
>>        bookList.insert(      element:  book  
>>                                   reorderBy:  .authorName 
>>                         dropOldVersions:  true                  )  
> 
> Sorry
> TedvG
> 
> 
> 
> 
> TedvG
>> On 12.03.2016, at 20:18, Ted F.A. van Gaalen <tedvgiosdev at gmail.com> wrote:
>> 
>> ( didn’t know it was on its way, so much to read here, missing things at times:
>> 
>> n.b. I’ve just read proposal SE-0046,
>> "Establish consistent label behavior across all parameters including first labels”
>> Imho it’s an improvement, but it still does not give the consistency/simplicity I would like to see)
>> 
>> To Jake and Erica: 
>>     Just in case you'd think this is a better idea, feel free to adjust your proposal with it. thank you.
>> 
>> ------------
>> 
>> Thank you Haravikk, 
>> but I’d prefer to have a label obligatory on the first parm as well, for consistency,
>> simplicity and readability.   
>> Also for clarity:
>>    A parameter name should not be part of a function name.
>> 
>> As in your second example:
>> 
>>>    func insert( element:      Element   ) { … }
>>>    func insert( contentsOf: Sequence) { … }
>> 
>> 
>> Always specifying  labels/names allows us also to have a simpler function syntax as well like so:
>> 
>>        func insert( element: Book inBooklist: Books reorder: true  dropOldVersions: true)       // no comma separators
>> 
>> or formatted like this for clarity : 
>> 
>>        func insert(      element:  Book   
>>                             reorderBy:   .authorName 
>>                  dropOldVersions:   true                      )  ->  Bool    
>>        { … } 
>> 
>> 
>> coincidentally, notice this is like in ObjC..  (which i liked) 
>> 
>> It also makes the logic with omitted default parameter simpler.
>> and would allow an arbitrary parameter sequence in the call, if needed. 
>> 
>> (i've appended this possibility later)
>> 
>> I prefer overloading functions in this kind of cases instead of:
>> 
>>  insertBook(...
>>  insertBooks(...
>>  insertBooksFromArray(...
>> 
>> but maybe that’s just my personal taste.
>> 
>> At the moment I can’t find conflicts with any other language construct, 
>> also for a new parameter list format without commas,
>> does anyone?
>> 
>> TedvG
>> 
>> 
>> 
>> 
>>> On 12.03.2016, at 19:22, Haravikk <swift-evolution at haravikk.me> wrote:
>>> 
>>> 
>>>> On 11 Mar 2016, at 20:33, Ted F.A. van Gaalen via swift-evolution <swift-evolution at swift.org> wrote:
>>>> 
>>>> When I started using Swift (on the whole a pleasant journey)
>>>> the most confusing thing to me was, and at times still is,  the parameter list,
>>>> 
>>>> 
>>>> I would prefer:
>>>> 
>>>> -uniform for functions(…) AND init(…)
>>>> -every parameter must be used with its name/label. Always, no exceptions.
>>>> -no shortcuts. 
>>>> -allow arbitrary parameter sequence.
>>>> which is possible and very easy to implement when you always have to use names.
>>>> -no trailing commas.
>>> 
>>> I agree, except for labels always being required; sometimes there’s just nothing to be gained by having a label, such as simple initialisers. Also, well-named functions ought to be clear what the first parameter is, for example:
>>> 
>>>    func insert(_ element:Element) { … }
>>> 
>>> No-one’s really going to wonder what a value going into a .insert() method is for. However, requiring the developer to choose to add the underscore (as I did above) to enable this gives a balance between the consistency of having all parameters labelled by default, and being able to omit them where it makes sense to.
>>> 
>>> In other words, the parameter can be omitted if its label wouldn’t add anything useful to the call-site. There could be an argument that if .insertContentsOf() were restructured then the parameter might become necessary, resulting in the following:
>>> 
>>>    func insert(element:Element) { … }
>>>    func insert(contentsOf:Sequence) { … }
>>> 
>>> But I think it’s still good for the API designer to have the option, as some cases just aren’t worth adding a label to (or would be redundant). It’s also handy for internal and private methods/initialisers that don’t need the extra clarity.
> 
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