> On May 10, 2016, at 5:51 PM, Dany St-Amant via swift-evolution 
> <[email protected]> wrote:
> 
> 
> On May 10, 2016, at 4:57 PM, Rob Napier via swift-evolution 
> <[email protected] <mailto:[email protected]>> wrote:
> 
>> On Tue, May 10, 2016 at 2:53 PM, Chris Lattner via swift-evolution 
>> <[email protected] <mailto:[email protected]>> wrote:
>> 
>>         * What is your evaluation of the proposal?
>> 
>> Trailing commas is clearly very useful in the collections case. While that 
>> case is more common than functions and tuples, I don't see any reason that 
>> collections should be treated as a special case. Why should some 
>> comma-separated lists allow trailing commas and some not?
>> 
>> This seems a reasonable move towards consistency and is useful in some cases 
>> while not harmful in others. When in doubt, I'd rather broad rules 
>> ("trailing commas are allowed in comma-separated lists") rather than special 
>> cases. This improves teachability.
> 
> If one look purely at commas, the inconsistency may be hard to explain, but 
> if one include the enclosing characters there are clear rules:
> 
> - within square brackets: trailing comma allowed
> - within parenthesis: trailing comma not allowed
> - within angle bracket: trailing comma not allowed

- within compound “conditions” (of while, if, guard): trailing comma not allowed

-Chris

> 
> Weird, I do not recall anyone mentioning generics in the original trailing 
> comma thread.
> 
> Dany
> 
>> 
>> It also improves diffs when functions pick up new parameters, particularly 
>> ones with default values. This is particularly common (and expected) in 
>> constructors. That's valuable.
>> 
>>  
>>         * Is the problem being addressed significant enough to warrant a 
>> change to Swift?
>> 
>> As a language rule simplification, I believe it's worth a change if it 
>> doesn't introduce problematic corner cases. The fact that it improves diffs 
>> is no less valuable for functions than it is for collections.
>> 
>>  
>>         * Does this proposal fit well with the feel and direction of Swift?
>> 
>> Yes; it definitely feels Swifty in the same way that it does for 
>> collections. There's no reason for Swift to treat them differently.
>> 
>>  
>>         * If you have used other languages or libraries with a similar 
>> feature, how do you feel that this proposal compares to those?
>> 
>> I've seen this in Perl, Python, and Go. Basically every language I've used 
>> that allows trailing commas in collections also allows them in function 
>> calls. In Go, the trailing comma is mandatory in some cases. This has been 
>> nice for consistency.
>> 
>>  
>>         * How much effort did you put into your review? A glance, a quick 
>> reading, or an in-depth study?
>> 
>> Quick reading.
>> 
>> -Rob
>> 
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